Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #15789 > unrolled thread

GA144 polyForth

Back to article view | Back to comp.lang.forth

Contents

  GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-09-27 14:16 -0700
    Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-09-29 01:20 -0700
      Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-09-30 11:05 -0400
        Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-09-30 09:06 -0700
          Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-09-30 14:29 -0400
            Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-09-30 19:56 -0700
      Re: GA144 polyForth Coos Haak <chforth@hccnet.nl> - 2012-09-30 21:54 +0200
      Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-01 11:18 -0700
        Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-10-01 23:40 -0700
          Re: GA144 polyForth "Elizabeth D. Rather" <erather@forth.com> - 2012-10-01 21:23 -1000
            Re: GA144 polyForth albert@spenarnc.xs4all.nl (Albert van der Horst) - 2012-10-05 19:19 +0000
          Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-04 23:04 -0700
    Re: GA144 polyForth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-01 10:28 -0500
      Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-01 11:19 -0700
        Re: GA144 polyForth Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-10-03 10:46 -0500
          Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-04 13:46 -0700
    Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-05 22:10 -0700
      Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-10-05 23:17 -0700
        Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-06 05:47 -0700
          Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-07 19:31 -0400
            Re: GA144 polyForth Bernd Paysan <bernd.paysan@gmx.de> - 2012-10-08 20:10 +0200
              Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-08 16:36 -0400
            Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-08 13:31 -0700
              Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-09 13:48 -0400
                Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-09 13:21 -0700
                  Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-09 17:08 -0400
                    Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-13 07:39 -0700
                      Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-13 14:28 -0400
                        Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-13 13:37 -0700
                          Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-13 16:54 -0400
                            Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-13 14:14 -0700
                              Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-13 17:30 -0400
                                Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-14 02:00 -0700
                                  Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-14 19:54 -0400
                                    Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-15 11:03 -0700
                                      Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-15 16:38 -0400
                                        Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-16 04:12 -0700
                                          Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-16 15:46 -0400
                                            Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-16 23:05 -0700
                                              Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-17 13:40 -0400
                                                Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-17 22:54 -0700
              Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-18 14:53 -0400
                Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-18 15:06 -0400
                  Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-18 15:09 -0400
                Re: GA144 polyForth Howerd <howerdo@yahoo.co.uk> - 2012-10-19 10:43 -0700
                  Re: GA144 polyForth rickman <gnuarm@gmail.com> - 2012-10-19 17:43 -0400
    Re: GA144 polyForth Mikael Nordman <oh2aun@invalid.com> - 2012-10-06 11:29 +0300
      Re: GA144 polyForth mhx@iae.nl (Marcel Hendrix) - 2012-10-06 11:14 +0200
        Re: GA144 polyForth Mikael Nordman <oh2aun@invalid.com> - 2012-10-06 16:08 +0300
      Re: GA144 polyForth Paul Rubin <no.email@nospam.invalid> - 2012-10-07 10:57 -0700

Page 2 of 3 — ← Prev page 1 [2] 3  Next page →

#16061

rickman wrote:
> The async processor goes to sleep until an input triggers it.  So why
> not use a clock for that input?  Then the GA144 core could utilize
> very little power just waiting.

You wrote it above: Chuck stops the clock, there is no clock to be used 
during sleeping time.

You can stop your clock in a serial interface after the stop bit, 
waiting for the next start bit (that's the purpose of the start bit, to 
provide a transition). You have to keep it running until the stop bit 
arrives.

-- 
Bernd Paysan
"If you want it done right, you have to do it yourself"
http://bernd-paysan.de/

[toc] | [prev] | [next] | [standalone]

#16069

On 10/8/2012 2:10 PM, Bernd Paysan wrote:
> rickman wrote:
>> The async processor goes to sleep until an input triggers it.  So why
>> not use a clock for that input?  Then the GA144 core could utilize
>> very little power just waiting.
>
> You wrote it above: Chuck stops the clock, there is no clock to be used
> during sleeping time.
>
> You can stop your clock in a serial interface after the stop bit,
> waiting for the next start bit (that's the purpose of the start bit, to
> provide a transition). You have to keep it running until the stop bit
> arrives.
>

I'm not sure what clock you are talking about.  I'm talking about a 
clock that is used to measure the period of the async bits, a 
requirement in an async protocol.

The UART node can be stopped waiting for a transition on the input. 
When the start bit transition happens on the async input the UART node 
sends a message to the timer node which counts external timing clock 
edges to measure time.  Meanwhile both nodes stop.  The timer node waits 
for clock edges and the UART node waits for a message from the timer 
node as well as further edges from the async input.  If the async input 
transitions first the bit is considered noise and the UART node starts 
over.  If the timer message arrives first this marks the middle of the 
start bit.  On subsequent timer messages the UART node reads the async 
input to get data and overhead bits.

I believe Chuck does not like to use an external clock because it is 
"extra" hardware and dissipates power.  But a 5 mW node is not exactly a 
"light" footprint to do nothing other than mark time.  I prefer the 
external clock.

Rick

[toc] | [prev] | [next] | [standalone]

#16068

On Monday, October 8, 2012 1:31:55 AM UTC+2, rickman wrote:
> On 10/6/2012 8:47 AM, Howerd wrote:
> 
>  > On Saturday, October 6, 2012 8:17:09 AM UTC+2, Paul Rubin wrote:
> 
>  >> Howerd<how....@yahoo.co.uk>  writes:
> 
>  >>> always going to be an overhead when you interface a GA144 to a clocked
> 
>  >>> system - since the GA144 runs asynchronously it has to run a polling
> 
>  >>> loop.  OK, it could idle between characters,
> 
>  >>
> 
>  >> Can't it use edge or level sensitive triggering on the port pin
> 
>  >> listening to the rs232 signal?  Then the GA node should block until the
> 
>  >> bit actually arrives.
> 
> 
> 
> That is how many MCUs time an async data stream, but they have to have a 
> 
> timer running so they can record the time of each transition.  The GA144 
> 
> is capable of implementing timers the same way by monitoring a clock 
> 
> input, but GA doesn't seem too interested in using this sort of 
> 
> operation.  Chuck's work seems to focus on no clock at all which is not 
> 
> practical.  He tried that with his video circuits and found the VGA 
> 
> signal from software loop timing was not stable enough to work with his 
> 
> monitor, and that is a *relaxed* application.
> 
> 
> 
> 
> 
>  >> It also occurs to me, I don't see any way for a GA node to enter a sleep
> 
>  >> for a given amount of time (say 100 microseconds), other than with a
> 
>  >> full-speed busy loop and that 8 ma of power consumption.  Compare that
> 
>  >> with microcontrollers that have very low powered counter-timers.
> 
> 
> 
> The async processor goes to sleep until an input triggers it.  So why 
> 
> not use a clock for that input?  Then the GA144 core could utilize very 
> 
> little power just waiting.
> 
> 
> 
> 
> 
>  >> 8 ma is more than I expected for a single node anyway.  It means over 1
> 
>  >> amp for all 144 nodes going at once, or several watts of power.  I
> 
>  >> didn't realize the ga144 could use that much.  Or, maybe the 8ma
> 
>  >> includes other stuff too.
> 
> 
> 
> 8 mA is too high for a single node.  One node is about 5 mW which would 
> 
> be around 3 mA I believe.  Still it's in that ballpark.  With all 144 
> 
> nodes running the power consumption is around three quarters of a Watt. 
> 
>   But the power consumption is instruction dependent, so you need to 
> 
> qualify that.  Just like the instruction rate is not 700 MIPS, but 
> 
> depends on your code the power consumption depends on your code too.
> 
> 
> 
> 
> 
>  >>> but a better way would be to use the on-chip SERDES instead of RS232
> 
> 
> 
> The SERDES is useless for talking to anything other than another GA 
> 
> device.  At least it is not supported in any other mode.  I'm not sure 
> 
> what protocol they use, but the clocking rate varies widely and so is 
> 
> hard to interface to other devices.  At least this is what I got out of 
> 
> the specs and lack of other info.
> 
> 
> 
> 
> 
>  >> The on-chip serdes is designed to only talk to other ga144's--do you
> 
>  >> mean to add a third ga144 to the board?
> 
>  >
> 
>  > Hi Paul,
> 
>  >
> 
>  >> ... I don't see any way for a GA node to enter a sleep
> 
>  >> for a given amount of time (say 100 microseconds), other than with a
> 
>  >> full-speed busy loop and that 8 ma of power consumption.
> 
>  > Yes - being asynchronous means that it has no idea of time.
> 
>  > But the only reason to wait for 100 ns is to synchronise with an 
> 
> external synchronous device - I'm stating the obvious here, but the 
> 
> GA144 is best suited to a fully asynchronous environment. If only the 
> 
> whole world was asynchronous - maybe it should be ;-)
> 
> 
> 
> To sync with a sync device it would just wait for the clock signal. 
> 
> Sync devices always use a clock.  The reason for waiting for some amount 
> 
> of time is to reduce power when you have nothing to do.  That means you 
> 
> need a timer to start the processor again.  That can be done by a timer 
> 
> node using an external clock.
> 
> 
> 
> The world will become async as soon as no one cares about speeds or times.
> 
> 
> 
> 
> 
>  >> The on-chip serdes is designed to only talk to other ga144's--do you
> 
>  >> mean to add a third ga144 to the board?
> 
>  > Nope - there are already two on the eval board, one of them is 
> 
> already acting as the interface to the synchronous world, via USB and 
> 
> serial comms. The two chips communicate via serdes.
> 
>  > But the serdes protocol is very simple, and self clocking (as it must 
> 
> be!), so maybe it could be implemented in software on another chip. The 
> 
> auto-baud software needs at least 19200 baud to not overflow the 18 bit 
> 
> counter, so a reasonably fast ARM should be able to keep up.
> 
> 
> 
> Are you mixing the SERDES and the software UART?  ARMs and many other 
> 
> processors implement software UARTs.  The SERDES runs at 100's of MHz. 
> 
> That is too fast for any CPU I am aware of to implement in software... 
> 
> assuming you knew the protocol.
> 
> 
> 
> 
> 
>  > There is a common theme here that I have noticed : The GA144 does 
> 
> things its own way, and it is difficult to interface it to the rest of 
> 
> the world which is doing things another way.
> 
> 
> 
> Duh, not only other digital systems, but lots of real world applications 
> 
> are hard to interface to the GA144.  Clocks tell us time and nearly 
> 
> everything is time based.
> 
> 
> 
> 
> 
>  > For example :
> 
>  > 1. It would be great, but non-trivial, to run a USB stack on a 
> 
> handful of F18's. Does this mean that the GA144 should have hardware USB 
> 
> support added, or that USB should changed for something simpler?
> 
> 
> 
> "Trivial"???  If that were true, GA would have done it already and put 
> 
> the code in the cores so it could boot from USB without the support 
> 
> chips from FTDI.
> 
> 
> 
> 
> 
>  > 2. SDRAM has a synchronous interface, but runs dynamically 
> 
> internally. I believe there are asynchronous RAMS, but thay are rare. 
> 
> Should the GA144 add a fast SDRAM module, or should the SDRAM chip be 
> 
> modified?
> 
> 
> 
> Async RAMs are not "rare", in fact that is what is on the GA144 eval 
> 
> board.  They aren't dense and they can be expensive, but the ones GA 
> 
> picked aren't too bad at around $5.
> 
> 
> 
> The problem with DRAMs (the generic term for all dynamic memory) is that 
> 
> they must be operated with both minimums and maximums on the timing 
> 
> signals.  The maximums are not too hard to meet, but typically designers 
> 
> want to run the DRAMs as fast as possible.  In the old days when DRAM 
> 
> interfaces were async (meaning no clock, not lack of timing constraints) 
> 
> it could be hard to optimize this interface.  SDRAM added a clock and 
> 
> gave the interface specific timing related to that clock.  I tried to 
> 
> design an SDRAM software interface for the GA144 and the big problem is 
> 
> trying to make the processors run the interface anywhere close to full 
> 
> speed.  I think I could get it to run at 50 MHz, but I can't be sure 
> 
> because they don't provide all the timing data for this sort of design. 
> 
>   But 50 MHz is not even half speed for the old single data rate SDRAM 
> 
> and is nowhere near the rates of DDR, DDR2 or DDR3.
> 
> 
> 
> Don't try to turn this into a problem with the memory devices.  They 
> 
> work just fine.  The problem is that GA won't put a proper memory 
> 
> interface on the chip which will run at memory speeds.  Instead they use 
> 
> software which runs much slower than optimal.
> 
> 
> 
> 
> 
>  > 3. Most software is written with the assumption of large amounts of 
> 
> flat addressed memory ( doesn't the 1M byte DOS limit feel really tight? 
> 
> ). But you can write software in very small, colorForth size chunks. If 
> 
> you spread these around a few F18's maybe you can create something 
> 
> really cool.
> 
> 
> 
> Yes, there are apps which will suit the GA144 small memory model, but 
> 
> they aren't the same apps that are typically running on >1MB devices. 
> 
> Remember the memory chunks are only 64 words per processor for both 
> 
> program and data.  So even with 144 of them you only have some 9 kWords 
> 
> of memory on chip.  Otherwise you have to load the programs and data 
> 
> from external memory.  Memory can be a real bottle neck unless you are 
> 
> running a pretty special app that fits the GA144.  I think digital 
> 
> receivers are one class of app that might work ok on this device, but I 
> 
> don't know of any others.
> 
> 
> 
> 
> 
>  > Going back to the original point - yes the GA144 can wait in an idle 
> 
> state for a pin to change state, but it must poll to get timings. Maybe 
> 
> a neighbouring F18 could wait for a change of state on a fixed clock 
> 
> signal, say at 16 * baudrate, then pass this on. This should get the 
> 
> power down to a minimum. Then again, maybe fixed baud rate is not the 
> 
> right way to talk to a GA144...
> 
> 
> 
> Yes, an external clock and a timer node is the way to get timing data. 
> 
> But to suggest that you shoudldn't talk to the GA144 with a fixed baud 
> 
> rate is not very realistic.  What part of the world is going to change 
> 
> to suit the GA144?
> 
> 
> 
> One way to do this is to work with a two wire interface, one wire for 
> 
> clock and one wire for data.  Whoever is sending the data sends the 
> 
> clock and the receiver has the option of slowing the clock like in I2C. 
> 
>   Or they could just add some hardware to handle this properly for 
> 
> whatever interface you don't like.
> 
> 
> 
> 
> 
>  > What would be interesting is to move the polyForth virtual machine to 
> 
> the target GA144, using serdes to communicate with it, and then measure 
> 
> the power.
> 
>  > Maybe I'll find some time over Xmas :-)
> 
>  >
> 
>  > Best regards,
> 
>  > Howerd
> 
> 
> 
> Rather than play with the board to measure things that don't likely 
> 
> matter to the world, what do you think you could use this device for 
> 
> that would be a better implementation than other devices?
> 
> 
> 
> Rick

Hi Rick,

> 8 mA is too high for a single node.  One node is about 5 mW which would 
> be around 3 mA I believe. 
This is consistant with three nodes being active - the comms, bitsy and stack.
Comms could wait for a clock signal, and the polyForth VM could be put into an idle mode, presumably.

>  > 1. It would be great, but non-trivial, to run a USB stack on a 
> handful of F18's. Does this mean that the GA144 should have hardware USB 
> support added, or that USB should changed for something simpler?
> "Trivial"???  
No, I said non-trivial! It would make a great PHD project :-)

> nearly everything is time based.
This is true, but this is just because everything is time based - its a self-fulfilling prophecy. The GA144 has no problem measuring time, just that it does so in its units. It can, of course, compare this to a reference clock if required.

> What part of the world is going to change to suit the GA144?
Any part that comes into contact with it - maybe the way things are done at the moment is not the only way. After all, Chuck designed the GA144 using colorForth...

> One way to do this is to work with a two wire interface...
Another is to use the GA144 serdes protocol. IIRC it it very simple, and since it is self-clocking, you can run it at lower speeds too. My comment about ARM chips being able to implement it in software was because it needs to be reasonably fast, I believe, so as not to overflow the 18 bit counters.

> Don't try to turn this into a problem with the memory devices.  They
> work just fine.  The problem is that GA won't put a proper memory
> interface on the chip which will run at memory speeds. 
I am not an expert on current memory technology, but it seems to me that any memory array returns its result when its ready, and most of the difficulty is in creating a synchronous interface to this. If this is true, what you are advocating is adding another synchronous interface to the GA144 to match the one on the RAM chip, and I am suggesting removing them both.

> Or they could just add some hardware to handle this properly for
> whatever interface you don't like. 
I have been checking out the latest chips for an embedded upgrade - MSP430, 8051, even PIC24. They all seem to be a collection of interface modules wrapped around some sort of processor, rather than a processor with modules.
Instead of doing this, GA supply the simplest possible hardware, and allow the end user to program appropriate interfaces. 
One solution is to put a conventional chip alongside a GA144 to handle all of these interfaces. Maybe this is a necessary evil to communicate with the rest of the world.

> what do you think you could use this device for
> that would be a better implementation than other devices? 
I intend to use the GA144 to interface to one or more antennas. I have a "gut feeeling" that if you remove all of the simplifying assumptions between electromagnetic radiation and software you might be able to find some new properties of both.
I am particularly interested in the orbital angular momentum ( OAM ) property of electromagnetic radiation - I want to go back to basics and see whether this can be measured easily with a GA144. I think the 6 GHz counter and VCO might be able to resolve OAM effects. We shall see...

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16106

On 10/8/2012 4:31 PM, Howerd wrote:
> On Monday, October 8, 2012 1:31:55 AM UTC+2, rickman wrote:
>>
>> what do you think you could use this device for
>> that would be a better implementation than other devices?
> I intend to use the GA144 to interface to one or more antennas. I have a"gut feeeling"
that if you remove all of the simplifying assumptions between 
electromagnetic radiation
and software you might be able to find some new properties of both.
> I am particularly interested in the orbital angular momentum ( OAM ) property of
electromagnetic radiation - I want to go back to basics and see whether 
this can be
measured easily with a GA144. I think the 6 GHz counter and VCO might be 
able to resolve
OAM effects. We shall see...
>
> Best regards,
> Howerd

OAM eh?  What aspects of the GA144 will enable this to be measured 
better than other methods?  The 5.6 GHz counter is just an ADC with a 
variable resolution vs. sample rate.  There are lots of ADC available 
with very high sample rates and much better resolution.

Rick

[toc] | [prev] | [next] | [standalone]

#16126

On Tuesday, October 9, 2012 7:48:14 PM UTC+2, rickman wrote:
> On 10/8/2012 4:31 PM, Howerd wrote:
> 
> > On Monday, October 8, 2012 1:31:55 AM UTC+2, rickman wrote:
> 
> >>
> 
> >> what do you think you could use this device for
> 
> >> that would be a better implementation than other devices?
> 
> > I intend to use the GA144 to interface to one or more antennas. I have a"gut feeeling"
> 
> that if you remove all of the simplifying assumptions between 
> 
> electromagnetic radiation
> 
> and software you might be able to find some new properties of both.
> 
> > I am particularly interested in the orbital angular momentum ( OAM ) property of
> 
> electromagnetic radiation - I want to go back to basics and see whether 
> 
> this can be
> 
> measured easily with a GA144. I think the 6 GHz counter and VCO might be 
> 
> able to resolve
> 
> OAM effects. We shall see...
> 
> >
> 
> > Best regards,
> 
> > Howerd
> 
> 
> 
> OAM eh?  What aspects of the GA144 will enable this to be measured 
> 
> better than other methods?  The 5.6 GHz counter is just an ADC with a 
> 
> variable resolution vs. sample rate.  There are lots of ADC available 
> 
> with very high sample rates and much better resolution.
> 
> 
> 
> Rick

Hi Rick,

> OAM eh?  What aspects of the GA144 will enable this to be measured 
> better than other methods?
The fact that there is minimum hardware between the antenna and the transistors that measure voltage - I am also looking for macroscopic quantum effects. 
If you read voltage using an ADC with amplifiers, filtering, anti-aliassing etc you are bound to observe what the theory says is there, because that theory was used to design the system. I want to get closer to the hardware.

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16129

On 10/9/2012 4:21 PM, Howerd wrote:
> On Tuesday, October 9, 2012 7:48:14 PM UTC+2, rickman wrote:
>> On 10/8/2012 4:31 PM, Howerd wrote:
>>
>>> On Monday, October 8, 2012 1:31:55 AM UTC+2, rickman wrote:
>>
>>>>
>>
>>>> what do you think you could use this device for
>>
>>>> that would be a better implementation than other devices?
>>
>>> I intend to use the GA144 to interface to one or more antennas. I have a"gut feeeling"
>>
>> that if you remove all of the simplifying assumptions between
>>
>> electromagnetic radiation
>>
>> and software you might be able to find some new properties of both.
>>
>>> I am particularly interested in the orbital angular momentum ( OAM ) property of
>>
>> electromagnetic radiation - I want to go back to basics and see whether
>>
>> this can be
>>
>> measured easily with a GA144. I think the 6 GHz counter and VCO might be
>>
>> able to resolve
>>
>> OAM effects. We shall see...
>>
>>>
>>
>>> Best regards,
>>
>>> Howerd
>>
>>
>>
>> OAM eh?  What aspects of the GA144 will enable this to be measured
>>
>> better than other methods?  The 5.6 GHz counter is just an ADC with a
>>
>> variable resolution vs. sample rate.  There are lots of ADC available
>>
>> with very high sample rates and much better resolution.
>>
>>
>>
>> Rick
>
> Hi Rick,
>
>> OAM eh?  What aspects of the GA144 will enable this to be measured
>> better than other methods?
> The fact that there is minimum hardware between the antenna and the transistors that measure voltage - I am also looking for macroscopic quantum effects.
> If you read voltage using an ADC with amplifiers, filtering, anti-aliassing etc you are bound to observe what the theory says is there, because that theory was used to design the system. I want to get closer to the hardware.
>
> Best regards,
> Howerd

What sample rate do you plan to use?  I guess I'm curious about how you 
plan to proceed.  I can't think of anything the GA144 can do that other 
ADC devices can't.

I quickly read about OAM after reading your first post and I don't think 
it is in defiance to existing theory.  I think no one (or few until 
recently) bothered to look for it.  If it can't be observed using 
scientific methods, then it won't be of much use in building transceivers.

BTW, the GA144 ADC has all the same limitations you mention above, if 
you think it gets around any of the above, check again.  The issue with 
anti-aliasing is not eliminated, it is just addressed in the ADC method 
to some extent.  If you read up you will find the GA144 ADC anti-alias 
functionality is pretty poor for most applications depending on the 
frequencies you wish to exclude and which you wish to include.

Rick

Rick

[toc] | [prev] | [next] | [standalone]

#16233

On Tuesday, October 9, 2012 11:08:34 PM UTC+2, rickman wrote:
> On 10/9/2012 4:21 PM, Howerd wrote:
> 
> > On Tuesday, October 9, 2012 7:48:14 PM UTC+2, rickman wrote:
> 
> >> On 10/8/2012 4:31 PM, Howerd wrote:
> 
> >>
> 
> >>> On Monday, October 8, 2012 1:31:55 AM UTC+2, rickman wrote:
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> what do you think you could use this device for
> 
> >>
> 
> >>>> that would be a better implementation than other devices?
> 
> >>
> 
> >>> I intend to use the GA144 to interface to one or more antennas. I have a"gut feeeling"
> 
> >>
> 
> >> that if you remove all of the simplifying assumptions between
> 
> >>
> 
> >> electromagnetic radiation
> 
> >>
> 
> >> and software you might be able to find some new properties of both.
> 
> >>
> 
> >>> I am particularly interested in the orbital angular momentum ( OAM ) property of
> 
> >>
> 
> >> electromagnetic radiation - I want to go back to basics and see whether
> 
> >>
> 
> >> this can be
> 
> >>
> 
> >> measured easily with a GA144. I think the 6 GHz counter and VCO might be
> 
> >>
> 
> >> able to resolve
> 
> >>
> 
> >> OAM effects. We shall see...
> 
> >>
> 
> >>>
> 
> >>
> 
> >>> Best regards,
> 
> >>
> 
> >>> Howerd
> 
> >>
> 
> >>
> 
> >>
> 
> >> OAM eh?  What aspects of the GA144 will enable this to be measured
> 
> >>
> 
> >> better than other methods?  The 5.6 GHz counter is just an ADC with a
> 
> >>
> 
> >> variable resolution vs. sample rate.  There are lots of ADC available
> 
> >>
> 
> >> with very high sample rates and much better resolution.
> 
> >>
> 
> >>
> 
> >>
> 
> >> Rick
> 
> >
> 
> > Hi Rick,
> 
> >
> 
> >> OAM eh?  What aspects of the GA144 will enable this to be measured
> 
> >> better than other methods?
> 
> > The fact that there is minimum hardware between the antenna and the transistors that measure voltage - I am also looking for macroscopic quantum effects.
> 
> > If you read voltage using an ADC with amplifiers, filtering, anti-aliassing etc you are bound to observe what the theory says is there, because that theory was used to design the system. I want to get closer to the hardware.
> 
> >
> 
> > Best regards,
> 
> > Howerd
> 
> 
> 
> What sample rate do you plan to use?  I guess I'm curious about how you 
> 
> plan to proceed.  I can't think of anything the GA144 can do that other 
> 
> ADC devices can't.
> 
> 
> 
> I quickly read about OAM after reading your first post and I don't think 
> 
> it is in defiance to existing theory.  I think no one (or few until 
> 
> recently) bothered to look for it.  If it can't be observed using 
> 
> scientific methods, then it won't be of much use in building transceivers.
> 
> 
> 
> BTW, the GA144 ADC has all the same limitations you mention above, if 
> 
> you think it gets around any of the above, check again.  The issue with 
> 
> anti-aliasing is not eliminated, it is just addressed in the ADC method 
> 
> to some extent.  If you read up you will find the GA144 ADC anti-alias 
> 
> functionality is pretty poor for most applications depending on the 
> 
> frequencies you wish to exclude and which you wish to include.
> 
> 
> 
> Rick
> 
> 
> 
> Rick

Hi Rick,

> What sample rate do you plan to use?
I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.

> I quickly read about OAM after reading your first post and I don't think
> it is in defiance to existing theory.  
Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
Very much existing theory.

The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.

> The issue with anti-aliasing is not eliminated, it is just addressed 
> in the ADC method to some extent.
My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage. 

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16243

On 10/13/2012 10:39 AM, Howerd wrote:
> Hi Rick,
>
>> What sample rate do you plan to use?
> I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.

I'm not sure I follow that.  How will you change your sample rate?  BTW, 
unless I don't understand the why the ADC works, every time you read the 
ADC it stops the counter for a short time.  Be aware of this as it may 
have an impact on your measurements if not accounted for.


>> I quickly read about OAM after reading your first post and I don't think
>> it is in defiance to existing theory.
> Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
> Very much existing theory.
>
> The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.

I still don't see how the GA144 ADC is any different for this than any 
other ADC.


>> The issue with anti-aliasing is not eliminated, it is just addressed
>> in the ADC method to some extent.
> My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.

Anti-aliasing is used to prevent signals above the Nyquist rate (1/2 
your sample rate) from affecting your measurement of baseband signals. 
If you aren't sampling in the conventional sense, there is no need to 
anti-alias.  But then I'm not clear what you *are* doing so I can't say 
for sure.

Rick

[toc] | [prev] | [next] | [standalone]

#16248

On Saturday, October 13, 2012 8:28:54 PM UTC+2, rickman wrote:
> On 10/13/2012 10:39 AM, Howerd wrote:
> 
> > Hi Rick,
> 
> >
> 
> >> What sample rate do you plan to use?
> 
> > I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.
> 
> 
> 
> I'm not sure I follow that.  How will you change your sample rate?  BTW, 
> 
> unless I don't understand the why the ADC works, every time you read the 
> 
> ADC it stops the counter for a short time.  Be aware of this as it may 
> 
> have an impact on your measurements if not accounted for.
> 
> 
> 
> 
> 
> >> I quickly read about OAM after reading your first post and I don't think
> 
> >> it is in defiance to existing theory.
> 
> > Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
> 
> > Very much existing theory.
> 
> >
> 
> > The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.
> 
> 
> 
> I still don't see how the GA144 ADC is any different for this than any 
> 
> other ADC.
> 
> 
> 
> 
> 
> >> The issue with anti-aliasing is not eliminated, it is just addressed
> 
> >> in the ADC method to some extent.
> 
> > My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.
> 
> 
> 
> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2 
> 
> your sample rate) from affecting your measurement of baseband signals. 
> 
> If you aren't sampling in the conventional sense, there is no need to 
> 
> anti-alias.  But then I'm not clear what you *are* doing so I can't say 
> 
> for sure.
> 
> 
> 
> Rick

Hi Rick,

> every time you read the ADC it stops the counter for a short time
There is no ADC, just a fast counter clocked by a VCO.

> I still don't see how the GA144 ADC is any different for this than any
> other ADC. 
Its no different to any other VCO and counter, but it is possible to pass the count value on to other cores to process, before passing it to the outside world. That and having five of these on each chip makes it very good for waht I want to do.

> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
> your sample rate) from affecting your measurement of baseband signals. 
If I run the VCO flat out at 5GHz, using it as a over-sampled one-bit ADC this should be OK for 10 MHZ signals. If this is possible, of course - I may need to drop it down to 2.5GHz.

> But then I'm not clear what you *are* doing so I can't say for sure. 
Maybe you have guesed that I'm not clear how to achieve what I want ;-)
But my direction is clear : for each antenna measure the electrical signal on an input pin as using the minimum number of transistors possible. Look at what really goes on when electicity interacts with antennas. Play it by ear...
I would like to start by repeating Chuck's measurement of wire length by timing a pulse bouncing back from the end of the wire.

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16250

On 10/13/2012 4:37 PM, Howerd wrote:
> On Saturday, October 13, 2012 8:28:54 PM UTC+2, rickman wrote:
>> On 10/13/2012 10:39 AM, Howerd wrote:
>>
>>> Hi Rick,
>>
>>>
>>
>>>> What sample rate do you plan to use?
>>
>>> I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.
>>
>>
>>
>> I'm not sure I follow that.  How will you change your sample rate?  BTW,
>>
>> unless I don't understand the why the ADC works, every time you read the
>>
>> ADC it stops the counter for a short time.  Be aware of this as it may
>>
>> have an impact on your measurements if not accounted for.
>>
>>
>>
>>
>>
>>>> I quickly read about OAM after reading your first post and I don't think
>>
>>>> it is in defiance to existing theory.
>>
>>> Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
>>
>>> Very much existing theory.
>>
>>>
>>
>>> The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.
>>
>>
>>
>> I still don't see how the GA144 ADC is any different for this than any
>>
>> other ADC.
>>
>>
>>
>>
>>
>>>> The issue with anti-aliasing is not eliminated, it is just addressed
>>
>>>> in the ADC method to some extent.
>>
>>> My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.
>>
>>
>>
>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
>>
>> your sample rate) from affecting your measurement of baseband signals.
>>
>> If you aren't sampling in the conventional sense, there is no need to
>>
>> anti-alias.  But then I'm not clear what you *are* doing so I can't say
>>
>> for sure.
>>
>>
>>
>> Rick
>
> Hi Rick,
>
>> every time you read the ADC it stops the counter for a short time
> There is no ADC, just a fast counter clocked by a VCO.

And the name they give it is an "ADC".  Analog in, Digital out...


>> I still don't see how the GA144 ADC is any different for this than any
>> other ADC.
> Its no different to any other VCO and counter, but it is possible to pass the count value on to other cores to process, before passing it to the outside world. That and having five of these on each chip makes it very good for waht I want to do.

The question is how will you make use of this data?  If you aren't going 
to treat it as the digital equivalent of an analog waveform, just what 
is it?


>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
>> your sample rate) from affecting your measurement of baseband signals.
> If I run the VCO flat out at 5GHz, using it as a over-sampled one-bit ADC this should be OK for 10 MHZ signals. If this is possible, of course - I may need to drop it down to 2.5GHz.

This statement clearly shows you don't understand what a VCO is.  You 
*don't* run the VCO "flat out".  The frequency varies with the input 
voltage, the voltage you are trying to measure.  The frequency varies 
with the input voltage and drives the counter.  By reading the counter 
at known times you can subtract successive values getting the difference 
which corresponds to the average voltage in that time period.  You can 
process the counter values as you wish, but the frequency of the VCO is 
not constant.

How do you think the VCO works?  Or are you planning to drive the VCO 
with Vss?  Then what do you do with the input voltage?


>> But then I'm not clear what you *are* doing so I can't say for sure.
> Maybe you have guesed that I'm not clear how to achieve what I want ;-)
> But my direction is clear : for each antenna measure the electrical signal on an input pin as using the minimum number of transistors possible. Look at what really goes on when electicity interacts with antennas. Play it by ear...
> I would like to start by repeating Chuck's measurement of wire length by timing a pulse bouncing back from the end of the wire.

Ok, that should be pretty simple, but make sure it is a long enough 
wire.  The CPU is fast, but not that fast.  The 700 MIPS number is a 
peak rate and you can't get too close to that with real code.

Rick

[toc] | [prev] | [next] | [standalone]

#16251

On Saturday, October 13, 2012 10:54:56 PM UTC+2, rickman wrote:
> On 10/13/2012 4:37 PM, Howerd wrote:
> 
> > On Saturday, October 13, 2012 8:28:54 PM UTC+2, rickman wrote:
> 
> >> On 10/13/2012 10:39 AM, Howerd wrote:
> 
> >>
> 
> >>> Hi Rick,
> 
> >>
> 
> >>>
> 
> >>
> 
> >>>> What sample rate do you plan to use?
> 
> >>
> 
> >>> I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.
> 
> >>
> 
> >>
> 
> >>
> 
> >> I'm not sure I follow that.  How will you change your sample rate?  BTW,
> 
> >>
> 
> >> unless I don't understand the why the ADC works, every time you read the
> 
> >>
> 
> >> ADC it stops the counter for a short time.  Be aware of this as it may
> 
> >>
> 
> >> have an impact on your measurements if not accounted for.
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>>> I quickly read about OAM after reading your first post and I don't think
> 
> >>
> 
> >>>> it is in defiance to existing theory.
> 
> >>
> 
> >>> Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
> 
> >>
> 
> >>> Very much existing theory.
> 
> >>
> 
> >>>
> 
> >>
> 
> >>> The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.
> 
> >>
> 
> >>
> 
> >>
> 
> >> I still don't see how the GA144 ADC is any different for this than any
> 
> >>
> 
> >> other ADC.
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>>> The issue with anti-aliasing is not eliminated, it is just addressed
> 
> >>
> 
> >>>> in the ADC method to some extent.
> 
> >>
> 
> >>> My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.
> 
> >>
> 
> >>
> 
> >>
> 
> >> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
> 
> >>
> 
> >> your sample rate) from affecting your measurement of baseband signals.
> 
> >>
> 
> >> If you aren't sampling in the conventional sense, there is no need to
> 
> >>
> 
> >> anti-alias.  But then I'm not clear what you *are* doing so I can't say
> 
> >>
> 
> >> for sure.
> 
> >>
> 
> >>
> 
> >>
> 
> >> Rick
> 
> >
> 
> > Hi Rick,
> 
> >
> 
> >> every time you read the ADC it stops the counter for a short time
> 
> > There is no ADC, just a fast counter clocked by a VCO.
> 
> 
> 
> And the name they give it is an "ADC".  Analog in, Digital out...
> 
> 
> 
> 
> 
> >> I still don't see how the GA144 ADC is any different for this than any
> 
> >> other ADC.
> 
> > Its no different to any other VCO and counter, but it is possible to pass the count value on to other cores to process, before passing it to the outside world. That and having five of these on each chip makes it very good for waht I want to do.
> 
> 
> 
> The question is how will you make use of this data?  If you aren't going 
> 
> to treat it as the digital equivalent of an analog waveform, just what 
> 
> is it?
> 
> 
> 
> 
> 
> >> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
> 
> >> your sample rate) from affecting your measurement of baseband signals.
> 
> > If I run the VCO flat out at 5GHz, using it as a over-sampled one-bit ADC this should be OK for 10 MHZ signals. If this is possible, of course - I may need to drop it down to 2.5GHz.
> 
> 
> 
> This statement clearly shows you don't understand what a VCO is.  You 
> 
> *don't* run the VCO "flat out".  The frequency varies with the input 
> 
> voltage, the voltage you are trying to measure.  The frequency varies 
> 
> with the input voltage and drives the counter.  By reading the counter 
> 
> at known times you can subtract successive values getting the difference 
> 
> which corresponds to the average voltage in that time period.  You can 
> 
> process the counter values as you wish, but the frequency of the VCO is 
> 
> not constant.
> 
> 
> 
> How do you think the VCO works?  Or are you planning to drive the VCO 
> 
> with Vss?  Then what do you do with the input voltage?
> 
> 
> 
> 
> 
> >> But then I'm not clear what you *are* doing so I can't say for sure.
> 
> > Maybe you have guesed that I'm not clear how to achieve what I want ;-)
> 
> > But my direction is clear : for each antenna measure the electrical signal on an input pin as using the minimum number of transistors possible. Look at what really goes on when electicity interacts with antennas. Play it by ear...
> 
> > I would like to start by repeating Chuck's measurement of wire length by timing a pulse bouncing back from the end of the wire.
> 
> 
> 
> Ok, that should be pretty simple, but make sure it is a long enough 
> 
> wire.  The CPU is fast, but not that fast.  The 700 MIPS number is a 
> 
> peak rate and you can't get too close to that with real code.
> 
> 
> 
> Rick

Hi Rick,

> And the name they give it is an "ADC"
Yes, OK, I meant not a conventional ADC, i.e. not delta-sigma, successive approximation, integrating etc...

> The question is how will you make use of this data?  If you aren't going
> to treat it as the digital equivalent of an analog waveform, just what
> is it? 
I want to interact with RF electrical signals using Forth, the same way I do with any other piece of hardware. 
So I don't know what I will do with the data - it depends on what I find.
I am hoping it will be like firing up a new processor with Forth for the first time and probing its peripherals, checking what I see against the databook.

> This statement clearly shows you don't understand what a VCO is. 
No, it shows that I did not express myself clearly ;-)
I will probably run the VCO with an input voltage very close to Vss, and just look at the bottom bit of the counter. This will give me a 1-bit ADC with a 5 GHz sampling rate, if you want to look at it that way.
I want to detect the smallest possible voltage and time variations, then average them over human-scale time periods. I'm also not interested in absolute values of either voltage or time, just deltas.

> The CPU is fast, but not that fast. 
True, but its the VCO that determines the sampling rate - 5 GHz has a wavelength of 5.9 cm. 50 GHz would be better...

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16252

On 10/13/2012 5:14 PM, Howerd wrote:
> On Saturday, October 13, 2012 10:54:56 PM UTC+2, rickman wrote:
>> On 10/13/2012 4:37 PM, Howerd wrote:
>>
>>> On Saturday, October 13, 2012 8:28:54 PM UTC+2, rickman wrote:
>>
>>>> On 10/13/2012 10:39 AM, Howerd wrote:
>>
>>>>
>>
>>>>> Hi Rick,
>>
>>>>
>>
>>>>>
>>
>>>>
>>
>>>>>> What sample rate do you plan to use?
>>
>>>>
>>
>>>>> I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>> I'm not sure I follow that.  How will you change your sample rate?  BTW,
>>
>>>>
>>
>>>> unless I don't understand the why the ADC works, every time you read the
>>
>>>>
>>
>>>> ADC it stops the counter for a short time.  Be aware of this as it may
>>
>>>>
>>
>>>> have an impact on your measurements if not accounted for.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>>> I quickly read about OAM after reading your first post and I don't think
>>
>>>>
>>
>>>>>> it is in defiance to existing theory.
>>
>>>>
>>
>>>>> Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
>>
>>>>
>>
>>>>> Very much existing theory.
>>
>>>>
>>
>>>>>
>>
>>>>
>>
>>>>> The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>> I still don't see how the GA144 ADC is any different for this than any
>>
>>>>
>>
>>>> other ADC.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>>>> The issue with anti-aliasing is not eliminated, it is just addressed
>>
>>>>
>>
>>>>>> in the ADC method to some extent.
>>
>>>>
>>
>>>>> My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
>>
>>>>
>>
>>>> your sample rate) from affecting your measurement of baseband signals.
>>
>>>>
>>
>>>> If you aren't sampling in the conventional sense, there is no need to
>>
>>>>
>>
>>>> anti-alias.  But then I'm not clear what you *are* doing so I can't say
>>
>>>>
>>
>>>> for sure.
>>
>>>>
>>
>>>>
>>
>>>>
>>
>>>> Rick
>>
>>>
>>
>>> Hi Rick,
>>
>>>
>>
>>>> every time you read the ADC it stops the counter for a short time
>>
>>> There is no ADC, just a fast counter clocked by a VCO.
>>
>>
>>
>> And the name they give it is an "ADC".  Analog in, Digital out...
>>
>>
>>
>>
>>
>>>> I still don't see how the GA144 ADC is any different for this than any
>>
>>>> other ADC.
>>
>>> Its no different to any other VCO and counter, but it is possible to pass the count value on to other cores to process, before passing it to the outside world. That and having five of these on each chip makes it very good for waht I want to do.
>>
>>
>>
>> The question is how will you make use of this data?  If you aren't going
>>
>> to treat it as the digital equivalent of an analog waveform, just what
>>
>> is it?
>>
>>
>>
>>
>>
>>>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
>>
>>>> your sample rate) from affecting your measurement of baseband signals.
>>
>>> If I run the VCO flat out at 5GHz, using it as a over-sampled one-bit ADC this should be OK for 10 MHZ signals. If this is possible, of course - I may need to drop it down to 2.5GHz.
>>
>>
>>
>> This statement clearly shows you don't understand what a VCO is.  You
>>
>> *don't* run the VCO "flat out".  The frequency varies with the input
>>
>> voltage, the voltage you are trying to measure.  The frequency varies
>>
>> with the input voltage and drives the counter.  By reading the counter
>>
>> at known times you can subtract successive values getting the difference
>>
>> which corresponds to the average voltage in that time period.  You can
>>
>> process the counter values as you wish, but the frequency of the VCO is
>>
>> not constant.
>>
>>
>>
>> How do you think the VCO works?  Or are you planning to drive the VCO
>>
>> with Vss?  Then what do you do with the input voltage?
>>
>>
>>
>>
>>
>>>> But then I'm not clear what you *are* doing so I can't say for sure.
>>
>>> Maybe you have guesed that I'm not clear how to achieve what I want ;-)
>>
>>> But my direction is clear : for each antenna measure the electrical signal on an input pin as using the minimum number of transistors possible. Look at what really goes on when electicity interacts with antennas. Play it by ear...
>>
>>> I would like to start by repeating Chuck's measurement of wire length by timing a pulse bouncing back from the end of the wire.
>>
>>
>>
>> Ok, that should be pretty simple, but make sure it is a long enough
>>
>> wire.  The CPU is fast, but not that fast.  The 700 MIPS number is a
>>
>> peak rate and you can't get too close to that with real code.
>>
>>
>>
>> Rick
>
> Hi Rick,
>
>> And the name they give it is an "ADC"
> Yes, OK, I meant not a conventional ADC, i.e. not delta-sigma, successive approximation, integrating etc...
>
>> The question is how will you make use of this data?  If you aren't going
>> to treat it as the digital equivalent of an analog waveform, just what
>> is it?
> I want to interact with RF electrical signals using Forth, the same way I do with any other piece of hardware.
> So I don't know what I will do with the data - it depends on what I find.
> I am hoping it will be like firing up a new processor with Forth for the first time and probing its peripherals, checking what I see against the databook.
>
>> This statement clearly shows you don't understand what a VCO is.
> No, it shows that I did not express myself clearly ;-)
> I will probably run the VCO with an input voltage very close to Vss, and just look at the bottom bit of the counter. This will give me a 1-bit ADC with a 5 GHz sampling rate, if you want to look at it that way.
> I want to detect the smallest possible voltage and time variations, then average them over human-scale time periods. I'm also not interested in absolute values of either voltage or time, just deltas.

Then you are looking for resolution, not VCO speed.  You can use the 
GA144 ADC for high resolution at very slow sample rates.  But if you 
don't know what you are looking for, I'm not sure how you will know when 
you find it.

Many other ADCs will give you very high resolution as well.


>> The CPU is fast, but not that fast.
> True, but its the VCO that determines the sampling rate - 5 GHz has a wavelength of 5.9 cm. 50 GHz would be better...

The rate of the VCO is not the sample rate of the ADC.  The VCO is 
analog at the interface to the input signal and the frequency is analog 
(continuously variable).  It is the counter that is digital.

Rick

[toc] | [prev] | [next] | [standalone]

#16262

On Saturday, October 13, 2012 11:30:44 PM UTC+2, rickman wrote:
> On 10/13/2012 5:14 PM, Howerd wrote:
> 
> > On Saturday, October 13, 2012 10:54:56 PM UTC+2, rickman wrote:
> 
> >> On 10/13/2012 4:37 PM, Howerd wrote:
> 
> >>
> 
> >>> On Saturday, October 13, 2012 8:28:54 PM UTC+2, rickman wrote:
> 
> >>
> 
> >>>> On 10/13/2012 10:39 AM, Howerd wrote:
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> Hi Rick,
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>> What sample rate do you plan to use?
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> I'm not intending to use the VCO as a conventional ADC, just observe the count as the voltage changes, so the sample rate will vary with voltage. Alos, mostly I want to measure timings.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> I'm not sure I follow that.  How will you change your sample rate?  BTW,
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> unless I don't understand the why the ADC works, every time you read the
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> ADC it stops the counter for a short time.  Be aware of this as it may
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> have an impact on your measurements if not accounted for.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>> I quickly read about OAM after reading your first post and I don't think
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>> it is in defiance to existing theory.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> Yes, OAM is predicted by quantum mechanics, and was first observed in 1935 IIRC.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> Very much existing theory.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> The theory that I want to get away from is where it is assumed that an electric field can be approximated by a scalar voltage. This may require 2, 3 or 4 receiving antennas and a transmitting antenna - measuring all signals in a synchronised way.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> I still don't see how the GA144 ADC is any different for this than any
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> other ADC.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>> The issue with anti-aliasing is not eliminated, it is just addressed
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>>> in the ADC method to some extent.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>> My plan is to make some measurements of timings on wires and antennas, present them on a PC using colorForth (booted from a USB stick using USBboot), then relate this to the theory... Anti-aliassing will no doubt come into this at some stage.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> your sample rate) from affecting your measurement of baseband signals.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> If you aren't sampling in the conventional sense, there is no need to
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> anti-alias.  But then I'm not clear what you *are* doing so I can't say
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> for sure.
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>>
> 
> >>
> 
> >>>> Rick
> 
> >>
> 
> >>>
> 
> >>
> 
> >>> Hi Rick,
> 
> >>
> 
> >>>
> 
> >>
> 
> >>>> every time you read the ADC it stops the counter for a short time
> 
> >>
> 
> >>> There is no ADC, just a fast counter clocked by a VCO.
> 
> >>
> 
> >>
> 
> >>
> 
> >> And the name they give it is an "ADC".  Analog in, Digital out...
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>>> I still don't see how the GA144 ADC is any different for this than any
> 
> >>
> 
> >>>> other ADC.
> 
> >>
> 
> >>> Its no different to any other VCO and counter, but it is possible to pass the count value on to other cores to process, before passing it to the outside world. That and having five of these on each chip makes it very good for waht I want to do.
> 
> >>
> 
> >>
> 
> >>
> 
> >> The question is how will you make use of this data?  If you aren't going
> 
> >>
> 
> >> to treat it as the digital equivalent of an analog waveform, just what
> 
> >>
> 
> >> is it?
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>>> Anti-aliasing is used to prevent signals above the Nyquist rate (1/2
> 
> >>
> 
> >>>> your sample rate) from affecting your measurement of baseband signals.
> 
> >>
> 
> >>> If I run the VCO flat out at 5GHz, using it as a over-sampled one-bit ADC this should be OK for 10 MHZ signals. If this is possible, of course - I may need to drop it down to 2.5GHz.
> 
> >>
> 
> >>
> 
> >>
> 
> >> This statement clearly shows you don't understand what a VCO is.  You
> 
> >>
> 
> >> *don't* run the VCO "flat out".  The frequency varies with the input
> 
> >>
> 
> >> voltage, the voltage you are trying to measure.  The frequency varies
> 
> >>
> 
> >> with the input voltage and drives the counter.  By reading the counter
> 
> >>
> 
> >> at known times you can subtract successive values getting the difference
> 
> >>
> 
> >> which corresponds to the average voltage in that time period.  You can
> 
> >>
> 
> >> process the counter values as you wish, but the frequency of the VCO is
> 
> >>
> 
> >> not constant.
> 
> >>
> 
> >>
> 
> >>
> 
> >> How do you think the VCO works?  Or are you planning to drive the VCO
> 
> >>
> 
> >> with Vss?  Then what do you do with the input voltage?
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>
> 
> >>>> But then I'm not clear what you *are* doing so I can't say for sure.
> 
> >>
> 
> >>> Maybe you have guesed that I'm not clear how to achieve what I want ;-)
> 
> >>
> 
> >>> But my direction is clear : for each antenna measure the electrical signal on an input pin as using the minimum number of transistors possible. Look at what really goes on when electicity interacts with antennas. Play it by ear...
> 
> >>
> 
> >>> I would like to start by repeating Chuck's measurement of wire length by timing a pulse bouncing back from the end of the wire.
> 
> >>
> 
> >>
> 
> >>
> 
> >> Ok, that should be pretty simple, but make sure it is a long enough
> 
> >>
> 
> >> wire.  The CPU is fast, but not that fast.  The 700 MIPS number is a
> 
> >>
> 
> >> peak rate and you can't get too close to that with real code.
> 
> >>
> 
> >>
> 
> >>
> 
> >> Rick
> 
> >
> 
> > Hi Rick,
> 
> >
> 
> >> And the name they give it is an "ADC"
> 
> > Yes, OK, I meant not a conventional ADC, i.e. not delta-sigma, successive approximation, integrating etc...
> 
> >
> 
> >> The question is how will you make use of this data?  If you aren't going
> 
> >> to treat it as the digital equivalent of an analog waveform, just what
> 
> >> is it?
> 
> > I want to interact with RF electrical signals using Forth, the same way I do with any other piece of hardware.
> 
> > So I don't know what I will do with the data - it depends on what I find.
> 
> > I am hoping it will be like firing up a new processor with Forth for the first time and probing its peripherals, checking what I see against the databook.
> 
> >
> 
> >> This statement clearly shows you don't understand what a VCO is.
> 
> > No, it shows that I did not express myself clearly ;-)
> 
> > I will probably run the VCO with an input voltage very close to Vss, and just look at the bottom bit of the counter. This will give me a 1-bit ADC with a 5 GHz sampling rate, if you want to look at it that way.
> 
> > I want to detect the smallest possible voltage and time variations, then average them over human-scale time periods. I'm also not interested in absolute values of either voltage or time, just deltas.
> 
> 
> 
> Then you are looking for resolution, not VCO speed.  You can use the 
> 
> GA144 ADC for high resolution at very slow sample rates.  But if you 
> 
> don't know what you are looking for, I'm not sure how you will know when 
> 
> you find it.
> 
> 
> 
> Many other ADCs will give you very high resolution as well.
> 
> 
> 
> 
> 
> >> The CPU is fast, but not that fast.
> 
> > True, but its the VCO that determines the sampling rate - 5 GHz has a wavelength of 5.9 cm. 50 GHz would be better...
> 
> 
> 
> The rate of the VCO is not the sample rate of the ADC.  The VCO is 
> 
> analog at the interface to the input signal and the frequency is analog 
> 
> (continuously variable).  It is the counter that is digital.
> 
> 
> 
> Rick

Hi Rick,

> Then you are looking for resolution, not VCO speed.
I am looking for both - detection of very small signals and very small time intervals.

> Many other ADCs will give you very high resolution as well. 
Digital resolution, yes, but analog resolution probably not.

> GA144 ADC for high resolution at very slow sample rates. 
I think you are using "resolution" in two different ways - there is analog resolution ( ability to detect a given change in voltage ), and ADC resolution ( number of bits ).

> The rate of the VCO is not the sample rate of the ADC
It is if it is a 1-bit ADC, sort of.

Its the analog resolution that I am interested in. I presume that the GA144's VCO is just a handful of transistors, so the bottom bit of the VCO count represents some very small change in the charge at the input pin.

Only with the GA144 do I get very sensitive analog inputs together with some fast processing, plus a high level (eForth or polyForth) IDE, all on chip.
I think this is magic :-)

Best regards,
Howerd

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16274

On 10/14/2012 5:00 AM, Howerd wrote:
> On Saturday, October 13, 2012 11:30:44 PM UTC+2, rickman wrote:
>>
>
> Hi Rick,
>
>> Then you are looking for resolution, not VCO speed.
> I am looking for both - detection of very small signals and very small time intervals.

In the GA144 the time interval will be determined by the CPU speed, I 
think the best you might get is around 10 ns, but I don't recall 
exactly, this might be for a clock timed loop that just takes the data 
and passes it on.  At that speed you will only get 4.3 ENOB (effective 
number of bits) theoretical max.  That's not very sensitive.


>> Many other ADCs will give you very high resolution as well.
> Digital resolution, yes, but analog resolution probably not.

Uh, yeah...  right.  It's time to learn about electronics.  You can 
think that you are going to toss existing theory out the window, but 
this is not the area that needs to be reinvented in order to learn 
about... what was it you were exploring again?


>> GA144 ADC for high resolution at very slow sample rates.
> I think you are using "resolution" in two different ways - there is analog resolution ( ability to detect a given change in voltage ), and ADC resolution ( number of bits ).

Yes, they are related by the gain of your amplifiers... uh, if you had 
amplifiers.  In the GA144 integrating ADC the analog resolution will be 
related to the sample rate...  if you have a sample rate.  The faster 
the sample rate the lower the analog resolution.  The 4.3 bits I mention 
above are over the analog range of about 1.2 volts, this is not well 
defined in the data sheet, so I'm not certain what this range is.  The 
ADC has a non-linear curve with more resolution in the center which is 
what I am assuming will be used.  Trying to get the full analog range of 
1.8 volts uses the compressed ranges near the limits with very low 
analog resolution.

The digital resolution is the number of bits.  The analog resolution is 
the analog range divided by the number of bits.  No magic, no new 
science to be invented.  The two are directly connected.  The only way 
to improve the analog resolution is to slow down the measurement to give 
longer integrations or to use an amplifier to get the same voltage range 
at the ADC input with a smaller range on the amplifier input.


>> The rate of the VCO is not the sample rate of the ADC
> It is if it is a 1-bit ADC, sort of.

Ok, you can go ahead and think of this as a 1 bit ADC but that buys you 
the worst possible resolution at the highest sample rate.


> Its the analog resolution that I am interested in. I presume that the GA144's VCO is just a handful of transistors, so the bottom bit of the VCO count represents some very small change in the charge at the input pin.

No, the counter bits do NOT correspond to anything at the input.  The 
counter free runs at a rate between about 3.5 GHz and 5.5 GHz.  The raw 
readings just keep incrementing and the absolute values mean nothing. 
You get an ADC reading by SUBTRACTING one reading from the next.  This 
DIFFERENCE is proportional to the integral of the voltage at the input 
over the sample period.

Actually, the range of the VCO in the linear area is only about 1.3 or 
1.4 GHz rather than the 2 GHz I used to calculate the ENOB.  The 
frequency range is what determines the difference range and the ADC 
resolution.


> Only with the GA144 do I get very sensitive analog inputs together with some fast processing, plus a high level (eForth or polyForth) IDE, all on chip.
> I think this is magic :-)

Yes, I expect it must seem like magic...  Or you could listen to people 
who don't see it as magic, but rather understand the details and can 
explain how it works as if it were engineering...

I'm pretty sure you won't see anything in your signals using the GA144 
that you can't see as well if not better using other devices.  For 
example, how well will your readings be time correlated using multiple 
ADCs in the GA144?  I can't get an answer to questions like this.  Or 
even how long the GA144 nodes take to come out of sleep when the input 
clock transitions.  These are *very* important numbers when using the 
ADC for signal acquisition.  Random delays here cause signal 
distortion/noise.

Rick

[toc] | [prev] | [next] | [standalone]

#16302

On Oct 15, 1:54 am, rickman <gnu...@gmail.com> wrote:
> On 10/14/2012 5:00 AM, Howerd wrote:
>
> > On Saturday, October 13, 2012 11:30:44 PM UTC+2, rickman wrote:
>
> > Hi Rick,
>
> >> Then you are looking for resolution, not VCO speed.
> > I am looking for both - detection of very small signals and very small time intervals.
>
> In the GA144 the time interval will be determined by the CPU speed, I
> think the best you might get is around 10 ns, but I don't recall
> exactly, this might be for a clock timed loop that just takes the data
> and passes it on.  At that speed you will only get 4.3 ENOB (effective
> number of bits) theoretical max.  That's not very sensitive.
>
> >> Many other ADCs will give you very high resolution as well.
> > Digital resolution, yes, but analog resolution probably not.
>
> Uh, yeah...  right.  It's time to learn about electronics.  You can
> think that you are going to toss existing theory out the window, but
> this is not the area that needs to be reinvented in order to learn
> about... what was it you were exploring again?
>
> >> GA144 ADC for high resolution at very slow sample rates.
> > I think you are using "resolution" in two different ways - there is analog resolution ( ability to detect a given change in voltage ), and ADC resolution ( number of bits ).
>
> Yes, they are related by the gain of your amplifiers... uh, if you had
> amplifiers.  In the GA144 integrating ADC the analog resolution will be
> related to the sample rate...  if you have a sample rate.  The faster
> the sample rate the lower the analog resolution.  The 4.3 bits I mention
> above are over the analog range of about 1.2 volts, this is not well
> defined in the data sheet, so I'm not certain what this range is.  The
> ADC has a non-linear curve with more resolution in the center which is
> what I am assuming will be used.  Trying to get the full analog range of
> 1.8 volts uses the compressed ranges near the limits with very low
> analog resolution.
>
> The digital resolution is the number of bits.  The analog resolution is
> the analog range divided by the number of bits.  No magic, no new
> science to be invented.  The two are directly connected.  The only way
> to improve the analog resolution is to slow down the measurement to give
> longer integrations or to use an amplifier to get the same voltage range
> at the ADC input with a smaller range on the amplifier input.
>
> >> The rate of the VCO is not the sample rate of the ADC
> > It is if it is a 1-bit ADC, sort of.
>
> Ok, you can go ahead and think of this as a 1 bit ADC but that buys you
> the worst possible resolution at the highest sample rate.
>
> > Its the analog resolution that I am interested in. I presume that the GA144's VCO is just a handful of transistors, so the bottom bit of the VCO count represents some very small change in the charge at the input pin.
>
> No, the counter bits do NOT correspond to anything at the input.  The
> counter free runs at a rate between about 3.5 GHz and 5.5 GHz.  The raw
> readings just keep incrementing and the absolute values mean nothing.
> You get an ADC reading by SUBTRACTING one reading from the next.  This
> DIFFERENCE is proportional to the integral of the voltage at the input
> over the sample period.
>
> Actually, the range of the VCO in the linear area is only about 1.3 or
> 1.4 GHz rather than the 2 GHz I used to calculate the ENOB.  The
> frequency range is what determines the difference range and the ADC
> resolution.
>
> > Only with the GA144 do I get very sensitive analog inputs together with some fast processing, plus a high level (eForth or polyForth) IDE, all on chip.
> > I think this is magic :-)
>
> Yes, I expect it must seem like magic...  Or you could listen to people
> who don't see it as magic, but rather understand the details and can
> explain how it works as if it were engineering...
>
> I'm pretty sure you won't see anything in your signals using the GA144
> that you can't see as well if not better using other devices.  For
> example, how well will your readings be time correlated using multiple
> ADCs in the GA144?  I can't get an answer to questions like this.  Or
> even how long the GA144 nodes take to come out of sleep when the input
> clock transitions.  These are *very* important numbers when using the
> ADC for signal acquisition.  Random delays here cause signal
> distortion/noise.
>
> Rick

Hi Rick,

> You can think that you are going to toss existing theory out the window,...
Not at all - I am looking for observable effects predicted by existing
theory.

> The digital resolution is the number of bits.
Ageed.

> The analog resolution is the analog range divided by the number of bits.
Only in the most simplistic model, ignoring oversampling, compressed
sampling, and maybe some other effects.

What concerns me here is that you seem to have such confidence in your
theoretical models of what goes on in electronic circuits.
Surely any theory only covers the available data, and must be modified
when new data comes long that doesn't fit in.
I want to look for new data...

I think the discussion of the GA144's ADC is missing the point. Let me
try to explain by describing two circuits :

1. An antenna, RF amplifier, anti-aliassing filter, very fast ADC,
fast DSP. Say some electrons wander down the antenna - what does it
take to observe a change in the DSP's output?

2. An antenna connected to the VCO input of an F18. The VCO is
presumably very few FET's arranged to oscillate, clocking a line of
edge triggered flip-flops. Bit 0 of the counter is averaged at, say,
100 Mhz rate.

I predict that #2 would be more sensitive, i.e. it would take fewer
electrons to make a visible change. There is also significantly more
possibility of quantum coupling efects occuring over just a few
transistors than over circuit #1.

Also, if I do not find any interesting new effects using the GA144,
there is not much more to be done, besides going to a faster chip
process, since this looks to me like the absolute minimum number of
components to convert a signal at the antenna to something useable.

I have nothing against circuit #1 - it does exactly what it is
designed to do.

Here are some questions that might be answered experimentally by the
GA144 :

1. does electrical current flowing down a wire have oribital angular
momentum (OAM), and if so could this be useful?
2. if a radio wave containing OAM arrives at two antennas, can the OAM
be detected by two F18 VCO's ?
3. is it posible to demodulate RF signals using an GA144 by applying
simple fast algorithms?

> how well will your readings be time correlated using multiple ADCs in the GA144?
This interests me too. There are two F18's with analog pins next to
each other, so it would be possible to have one waiting for the other
with just the latching time of the ports between them. I would expect
jitter of around 10ns if the F18 cores are also doing something useful
with the data, but this is really just a guess.

> Or even how long the GA144 nodes take to come out of sleep when the input clock transitions.
As I understand this, the GA144 doesn't "go to sleep" - it is clocked
by receiving an instruction on one of its ports.
So no time at all.
The VCO-counting-ADC is free running, so any two would be independent.
You could synchronise reading them, but the read pulse would not be
connected to the VCO, so I would expect a lot of jitter. I think the
GA144's ADC's are good for audio maybe, but not for low jitter, high
speed, high resolution measurements.

In my experience, it is best never to use ADC's, but to convert the
signal you want to measure into a time period. The GA144 is good at
measuring time periods...

I'm sorry if this sounds like the classic Forth question and answer :
Q. how would you do X in Forth? A. don't do X, do Y.

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16306

On 10/15/2012 2:03 PM, Howerd wrote:
> On Oct 15, 1:54 am, rickman<gnu...@gmail.com>  wrote:
>> On 10/14/2012 5:00 AM, Howerd wrote:
>>
>>> On Saturday, October 13, 2012 11:30:44 PM UTC+2, rickman wrote:
>>
>>> Hi Rick,
>>
>>>> Then you are looking for resolution, not VCO speed.
>>> I am looking for both - detection of very small signals and very small time intervals.
>>
>> In the GA144 the time interval will be determined by the CPU speed, I
>> think the best you might get is around 10 ns, but I don't recall
>> exactly, this might be for a clock timed loop that just takes the data
>> and passes it on.  At that speed you will only get 4.3 ENOB (effective
>> number of bits) theoretical max.  That's not very sensitive.
>>
>>>> Many other ADCs will give you very high resolution as well.
>>> Digital resolution, yes, but analog resolution probably not.
>>
>> Uh, yeah...  right.  It's time to learn about electronics.  You can
>> think that you are going to toss existing theory out the window, but
>> this is not the area that needs to be reinvented in order to learn
>> about... what was it you were exploring again?
>>
>>>> GA144 ADC for high resolution at very slow sample rates.
>>> I think you are using "resolution" in two different ways - there is analog resolution ( ability to detect a given change in voltage ), and ADC resolution ( number of bits ).
>>
>> Yes, they are related by the gain of your amplifiers... uh, if you had
>> amplifiers.  In the GA144 integrating ADC the analog resolution will be
>> related to the sample rate...  if you have a sample rate.  The faster
>> the sample rate the lower the analog resolution.  The 4.3 bits I mention
>> above are over the analog range of about 1.2 volts, this is not well
>> defined in the data sheet, so I'm not certain what this range is.  The
>> ADC has a non-linear curve with more resolution in the center which is
>> what I am assuming will be used.  Trying to get the full analog range of
>> 1.8 volts uses the compressed ranges near the limits with very low
>> analog resolution.
>>
>> The digital resolution is the number of bits.  The analog resolution is
>> the analog range divided by the number of bits.  No magic, no new
>> science to be invented.  The two are directly connected.  The only way
>> to improve the analog resolution is to slow down the measurement to give
>> longer integrations or to use an amplifier to get the same voltage range
>> at the ADC input with a smaller range on the amplifier input.
>>
>>>> The rate of the VCO is not the sample rate of the ADC
>>> It is if it is a 1-bit ADC, sort of.
>>
>> Ok, you can go ahead and think of this as a 1 bit ADC but that buys you
>> the worst possible resolution at the highest sample rate.
>>
>>> Its the analog resolution that I am interested in. I presume that the GA144's VCO is just a handful of transistors, so the bottom bit of the VCO count represents some very small change in the charge at the input pin.
>>
>> No, the counter bits do NOT correspond to anything at the input.  The
>> counter free runs at a rate between about 3.5 GHz and 5.5 GHz.  The raw
>> readings just keep incrementing and the absolute values mean nothing.
>> You get an ADC reading by SUBTRACTING one reading from the next.  This
>> DIFFERENCE is proportional to the integral of the voltage at the input
>> over the sample period.
>>
>> Actually, the range of the VCO in the linear area is only about 1.3 or
>> 1.4 GHz rather than the 2 GHz I used to calculate the ENOB.  The
>> frequency range is what determines the difference range and the ADC
>> resolution.
>>
>>> Only with the GA144 do I get very sensitive analog inputs together with some fast processing, plus a high level (eForth or polyForth) IDE, all on chip.
>>> I think this is magic :-)
>>
>> Yes, I expect it must seem like magic...  Or you could listen to people
>> who don't see it as magic, but rather understand the details and can
>> explain how it works as if it were engineering...
>>
>> I'm pretty sure you won't see anything in your signals using the GA144
>> that you can't see as well if not better using other devices.  For
>> example, how well will your readings be time correlated using multiple
>> ADCs in the GA144?  I can't get an answer to questions like this.  Or
>> even how long the GA144 nodes take to come out of sleep when the input
>> clock transitions.  These are *very* important numbers when using the
>> ADC for signal acquisition.  Random delays here cause signal
>> distortion/noise.
>>
>> Rick
>
> Hi Rick,
>
>> You can think that you are going to toss existing theory out the window,...
> Not at all - I am looking for observable effects predicted by existing
> theory.

Then why do you need to use something that you feel will uncover things 
that haven't been seen before?  If it fits in with existing theory, then 
it should be observable with existing technology.


>> The digital resolution is the number of bits.
> Ageed.
>
>> The analog resolution is the analog range divided by the number of bits.
> Only in the most simplistic model, ignoring oversampling, compressed
> sampling, and maybe some other effects.
>
> What concerns me here is that you seem to have such confidence in your
> theoretical models of what goes on in electronic circuits.
> Surely any theory only covers the available data, and must be modified
> when new data comes long that doesn't fit in.
> I want to look for new data...

That's fine, but my point is that you have said nothing understandable 
that indicates the GA144 will do anything any other ADC can't do.  You 
talk about 5 GHz as if it is the sample rate and it isn't, you talk 
about the counter lsb as if this is somehow related to a very low 
sensitivity voltage and it isn't.  Before you can even make a 
measurement with the GA144 ADC you need to understand how it works and 
how it doesn't work.


> I think the discussion of the GA144's ADC is missing the point. Let me
> try to explain by describing two circuits :
>
> 1. An antenna, RF amplifier, anti-aliassing filter, very fast ADC,
> fast DSP. Say some electrons wander down the antenna - what does it
> take to observe a change in the DSP's output?

Your use of "DSP's output" is not clear.  Do you mean the ADC output? 
To see a change you need enough voltage at the input to the ADC to cross 
one of the many thresholds in the ADC.  This will of course on the 
voltage change at the antenna, the characteristics of the filter and the 
gain of the amplifier.


> 2. An antenna connected to the VCO input of an F18. The VCO is
> presumably very few FET's arranged to oscillate, clocking a line of
> edge triggered flip-flops. Bit 0 of the counter is averaged at, say,
> 100 Mhz rate.

This made sense until you talk about bit 0 "averaged at" 100 MHz.  I 
don't know what that means.  The frequency of the VCO output will vary 
between the values I listed the other day.  Bit 0 will toggle at half 
that rate.  Of course, this rate varies with the voltage of the input 
signal.


> I predict that #2 would be more sensitive, i.e. it would take fewer
> electrons to make a visible change. There is also significantly more
> possibility of quantum coupling efects occuring over just a few
> transistors than over circuit #1.

Quantum coupling to what?  How will the VCO frequency change with 
quantum coupling?  What in the GA144 will let you detect quantum 
coupling if it does happen?  I don't recall a quantum coupling detector 
listed in the data sheet.

I don't see how the GA144 is any more sensitive to the antenna signal 
than the GA144.  In fact the GA144 can be fairly insensitive depending 
on the sample rate.  At high sample rates it is very insensitive.


> Also, if I do not find any interesting new effects using the GA144,
> there is not much more to be done, besides going to a faster chip
> process, since this looks to me like the absolute minimum number of
> components to convert a signal at the antenna to something useable.
>
> I have nothing against circuit #1 - it does exactly what it is
> designed to do.
>
> Here are some questions that might be answered experimentally by the
> GA144 :
>
> 1. does electrical current flowing down a wire have oribital angular
> momentum (OAM), and if so could this be useful?

If you are going to measure this, you need to predict outcomes.  What 
will be observed if you do detect OAM?  What will be observed if you 
don't detect OAM?  Until you can answer that question there is no 
experiment really.


> 2. if a radio wave containing OAM arrives at two antennas, can the OAM
> be detected by two F18 VCO's ?

I give up, can it?


> 3. is it posible to demodulate RF signals using an GA144 by applying
> simple fast algorithms?

I can answer this one, yes.  Just like you can demodulate RF signals 
using simple, fast algorithms on any other processor.


>> how well will your readings be time correlated using multiple ADCs in the GA144?
> This interests me too. There are two F18's with analog pins next to
> each other, so it would be possible to have one waiting for the other
> with just the latching time of the ports between them. I would expect
> jitter of around 10ns if the F18 cores are also doing something useful
> with the data, but this is really just a guess.

10 ns is a long time in the RF world.  If you sample a 100 MHz carrier 
(middle of the FM band) this is an entire cycle of the carrier, 360 
degrees, 2 pi radians, lots of confusion possible here.

Some folks posting here who worked with GA claim there can be low double 
digit ps of uncertainty in the sampling time, but I think this depends 
on a great many factors and I can't get answers out of GA to confirm any 
of it.


>> Or even how long the GA144 nodes take to come out of sleep when the input clock transitions.
> As I understand this, the GA144 doesn't "go to sleep" - it is clocked
> by receiving an instruction on one of its ports.
> So no time at all.

Hmmm, a difference of nomenclature.  When I say "sleep" and you say 
"clocked" we are talking about the same thing.  While it is waiting for 
the input transition it is "asleep".  Or you could say it is "crouched" 
like a cat, waiting to "spring" and "pounce" on its "prey", opps, I mean 
"data".  Cat like reflexes!  Yes, I want Schrödinger's cat in my CPUs...


> The VCO-counting-ADC is free running, so any two would be independent.
> You could synchronise reading them, but the read pulse would not be
> connected to the VCO, so I would expect a lot of jitter. I think the
> GA144's ADC's are good for audio maybe, but not for low jitter, high
> speed, high resolution measurements.

I thought you were interested in high resolution???  Now I'm very confused.


> In my experience, it is best never to use ADC's, but to convert the
> signal you want to measure into a time period. The GA144 is good at
> measuring time periods...

Oh, do you have lots of experience with this?  How does the GA144 
measure time periods?  I think Chuck does it by tying the ADC input to 
Vdd which will run the VCO at max rate.  After calibrating (somehow) he 
examines the counter at the start and the end of a time period.  Is this 
what you mean?  Notice that there is no input signal in this example. 
Where would you connect your input signal?


> I'm sorry if this sounds like the classic Forth question and answer :
> Q. how would you do X in Forth? A. don't do X, do Y.

I'm still confused, what is X again?  No, what is Y?  No, I am asking 
"why", no, I want to know "ex"...

Who's on first?

Rick

[toc] | [prev] | [next] | [standalone]

#16342

On Oct 15, 10:38 pm, rickman <gnu...@gmail.com> wrote:
> On 10/15/2012 2:03 PM, Howerd wrote:
>
> > On Oct 15, 1:54 am, rickman<gnu...@gmail.com>  wrote:
> >> On 10/14/2012 5:00 AM, Howerd wrote:
>
> >>> On Saturday, October 13, 2012 11:30:44 PM UTC+2, rickman wrote:
>
> >>> Hi Rick,
>
> >>>> Then you are looking for resolution, not VCO speed.
> >>> I am looking for both - detection of very small signals and very small time intervals.
>
> >> In the GA144 the time interval will be determined by the CPU speed, I
> >> think the best you might get is around 10 ns, but I don't recall
> >> exactly, this might be for a clock timed loop that just takes the data
> >> and passes it on.  At that speed you will only get 4.3 ENOB (effective
> >> number of bits) theoretical max.  That's not very sensitive.
>
> >>>> Many other ADCs will give you very high resolution as well.
> >>> Digital resolution, yes, but analog resolution probably not.
>
> >> Uh, yeah...  right.  It's time to learn about electronics.  You can
> >> think that you are going to toss existing theory out the window, but
> >> this is not the area that needs to be reinvented in order to learn
> >> about... what was it you were exploring again?
>
> >>>> GA144 ADC for high resolution at very slow sample rates.
> >>> I think you are using "resolution" in two different ways - there is analog resolution ( ability to detect a given change in voltage ), and ADC resolution ( number of bits ).
>
> >> Yes, they are related by the gain of your amplifiers... uh, if you had
> >> amplifiers.  In the GA144 integrating ADC the analog resolution will be
> >> related to the sample rate...  if you have a sample rate.  The faster
> >> the sample rate the lower the analog resolution.  The 4.3 bits I mention
> >> above are over the analog range of about 1.2 volts, this is not well
> >> defined in the data sheet, so I'm not certain what this range is.  The
> >> ADC has a non-linear curve with more resolution in the center which is
> >> what I am assuming will be used.  Trying to get the full analog range of
> >> 1.8 volts uses the compressed ranges near the limits with very low
> >> analog resolution.
>
> >> The digital resolution is the number of bits.  The analog resolution is
> >> the analog range divided by the number of bits.  No magic, no new
> >> science to be invented.  The two are directly connected.  The only way
> >> to improve the analog resolution is to slow down the measurement to give
> >> longer integrations or to use an amplifier to get the same voltage range
> >> at the ADC input with a smaller range on the amplifier input.
>
> >>>> The rate of the VCO is not the sample rate of the ADC
> >>> It is if it is a 1-bit ADC, sort of.
>
> >> Ok, you can go ahead and think of this as a 1 bit ADC but that buys you
> >> the worst possible resolution at the highest sample rate.
>
> >>> Its the analog resolution that I am interested in. I presume that the GA144's VCO is just a handful of transistors, so the bottom bit of the VCO count represents some very small change in the charge at the input pin.
>
> >> No, the counter bits do NOT correspond to anything at the input.  The
> >> counter free runs at a rate between about 3.5 GHz and 5.5 GHz.  The raw
> >> readings just keep incrementing and the absolute values mean nothing.
> >> You get an ADC reading by SUBTRACTING one reading from the next.  This
> >> DIFFERENCE is proportional to the integral of the voltage at the input
> >> over the sample period.
>
> >> Actually, the range of the VCO in the linear area is only about 1.3 or
> >> 1.4 GHz rather than the 2 GHz I used to calculate the ENOB.  The
> >> frequency range is what determines the difference range and the ADC
> >> resolution.
>
> >>> Only with the GA144 do I get very sensitive analog inputs together with some fast processing, plus a high level (eForth or polyForth) IDE, all on chip.
> >>> I think this is magic :-)
>
> >> Yes, I expect it must seem like magic...  Or you could listen to people
> >> who don't see it as magic, but rather understand the details and can
> >> explain how it works as if it were engineering...
>
> >> I'm pretty sure you won't see anything in your signals using the GA144
> >> that you can't see as well if not better using other devices.  For
> >> example, how well will your readings be time correlated using multiple
> >> ADCs in the GA144?  I can't get an answer to questions like this.  Or
> >> even how long the GA144 nodes take to come out of sleep when the input
> >> clock transitions.  These are *very* important numbers when using the
> >> ADC for signal acquisition.  Random delays here cause signal
> >> distortion/noise.
>
> >> Rick
>
> > Hi Rick,
>
> >> You can think that you are going to toss existing theory out the window,...
> > Not at all - I am looking for observable effects predicted by existing
> > theory.
>
> Then why do you need to use something that you feel will uncover things
> that haven't been seen before?  If it fits in with existing theory, then
> it should be observable with existing technology.
>
> >> The digital resolution is the number of bits.
> > Ageed.
>
> >> The analog resolution is the analog range divided by the number of bits.
> > Only in the most simplistic model, ignoring oversampling, compressed
> > sampling, and maybe some other effects.
>
> > What concerns me here is that you seem to have such confidence in your
> > theoretical models of what goes on in electronic circuits.
> > Surely any theory only covers the available data, and must be modified
> > when new data comes long that doesn't fit in.
> > I want to look for new data...
>
> That's fine, but my point is that you have said nothing understandable
> that indicates the GA144 will do anything any other ADC can't do.  You
> talk about 5 GHz as if it is the sample rate and it isn't, you talk
> about the counter lsb as if this is somehow related to a very low
> sensitivity voltage and it isn't.  Before you can even make a
> measurement with the GA144 ADC you need to understand how it works and
> how it doesn't work.
>
> > I think the discussion of the GA144's ADC is missing the point. Let me
> > try to explain by describing two circuits :
>
> > 1. An antenna, RF amplifier, anti-aliassing filter, very fast ADC,
> > fast DSP. Say some electrons wander down the antenna - what does it
> > take to observe a change in the DSP's output?
>
> Your use of "DSP's output" is not clear.  Do you mean the ADC output?
> To see a change you need enough voltage at the input to the ADC to cross
> one of the many thresholds in the ADC.  This will of course on the
> voltage change at the antenna, the characteristics of the filter and the
> gain of the amplifier.
>
> > 2. An antenna connected to the VCO input of an F18. The VCO is
> > presumably very few FET's arranged to oscillate, clocking a line of
> > edge triggered flip-flops. Bit 0 of the counter is averaged at, say,
> > 100 Mhz rate.
>
> This made sense until you talk about bit 0 "averaged at" 100 MHz.  I
> don't know what that means.  The frequency of the VCO output will vary
> between the values I listed the other day.  Bit 0 will toggle at half
> that rate.  Of course, this rate varies with the voltage of the input
> signal.
>
> > I predict that #2 would be more sensitive, i.e. it would take fewer
> > electrons to make a visible change. There is also significantly more
> > possibility of quantum coupling efects occuring over just a few
> > transistors than over circuit #1.
>
> Quantum coupling to what?  How will the VCO frequency change with
> quantum coupling?  What in the GA144 will let you detect quantum
> coupling if it does happen?  I don't recall a quantum coupling detector
> listed in the data sheet.
>
> I don't see how the GA144 is any more sensitive to the antenna signal
> than the GA144.  In fact the GA144 can be fairly insensitive depending
> on the sample rate.  At high sample rates it is very insensitive.
>
> > Also, if I do not find any interesting new effects using the GA144,
> > there is not much more to be done, besides going to a faster chip
> > process, since this looks to me like the absolute minimum number of
> > components to convert a signal at the antenna to something useable.
>
> > I have nothing against circuit #1 - it does exactly what it is
> > designed to do.
>
> > Here are some questions that might be answered experimentally by the
> > GA144 :
>
> > 1. does electrical current flowing down a wire have oribital angular
> > momentum (OAM), and if so could this be useful?
>
> If you are going to measure this, you need to predict outcomes.  What
> will be observed if you do detect OAM?  What will be observed if you
> don't detect OAM?  Until you can answer that question there is no
> experiment really.
>
> > 2. if a radio wave containing OAM arrives at two antennas, can the OAM
> > be detected by two F18 VCO's ?
>
> I give up, can it?
>
> > 3. is it posible to demodulate RF signals using an GA144 by applying
> > simple fast algorithms?
>
> I can answer this one, yes.  Just like you can demodulate RF signals
> using simple, fast algorithms on any other processor.
>
> >> how well will your readings be time correlated using multiple ADCs in the GA144?
> > This interests me too. There are two F18's with analog pins next to
> > each other, so it would be possible to have one waiting for the other
> > with just the latching time of the ports between them. I would expect
> > jitter of around 10ns if the F18 cores are also doing something useful
> > with the data, but this is really just a guess.
>
> 10 ns is a long time in the RF world.  If you sample a 100 MHz carrier
> (middle of the FM band) this is an entire cycle of the carrier, 360
> degrees, 2 pi radians, lots of confusion possible here.
>
> Some folks posting here who worked with GA claim there can be low double
> digit ps of uncertainty in the sampling time, but I think this depends
> on a great many factors and I can't get answers out of GA to confirm any
> of it.
>
> >> Or even how long the GA144 nodes take to come out of sleep when the input clock transitions.
> > As I understand this, the GA144 doesn't "go to sleep" - it is clocked
> > by receiving an instruction on one of its ports.
> > So no time at all.
>
> Hmmm, a difference of nomenclature.  When I say "sleep" and you say
> "clocked" we are talking about the same thing.  While it is waiting for
> the input transition it is "asleep".  Or you could say it is "crouched"
> like a cat, waiting to "spring" and "pounce" on its "prey", opps, I mean
> "data".  Cat like reflexes!  Yes, I want Schrödinger's cat in my CPUs...
>
> > The VCO-counting-ADC is free running, so any two would be independent.
> > You could synchronise reading them, but the read pulse would not be
> > connected to the VCO, so I would expect a lot of jitter. I think the
> > GA144's ADC's are good for audio maybe, but not for low jitter, high
> > speed, high resolution measurements.
>
> I thought you were interested in high resolution???  Now I'm very confused.
>
> > In my experience, it is best never to use ADC's, but to convert the
> > signal you want to measure into a time period. The GA144 is good at
> > measuring time periods...
>
> Oh, do you have lots of experience with this?  How does the GA144
> measure time periods?  I think Chuck does it by tying the ADC input to
> Vdd which will run the VCO at max rate.  After calibrating (somehow) he
> examines the counter at the start and the end of a time period.  Is this
> what you mean?  Notice that there is no input signal in this example.
> Where would you connect your input signal?
>
> > I'm sorry if this sounds like the classic Forth question and answer :
> > Q. how would you do X in Forth? A. don't do X, do Y.
>
> I'm still confused, what is X again?  No, what is Y?  No, I am asking
> "why", no, I want to know "ex"...
>
> Who's on first?
>
> Rick
>
>

Hi Rick,

> If it fits in with existing theory, then it should be observable with existing technology.
Yes, the GA144 is existing technology...

> you have said nothing understandable that indicates the GA144 will do anything any other ADC can't do.
The GA144 is very simple, so the electrical path between input pin and
counter output is very short.
This might allow effects to be observed that would be smoothed out by
amplifiers, filters and conventional ADCs.

> You talk about 5 GHz as if it is the sample rate and it isn't,
If you clock a counter at 5GHz +/-100MHz, as the frequency changes the
value of bit 0 of the counter when observed every 10 ns will change,
and this value, if summed over a long period of time, will reflect the
change in frequency. Since this is a VCO a small change in voltage
will cause a small change in frequency which will cause a change in
the summed count value.
It depends on exactly how you define these terms, but you could view
this as an oversampled 1 bit ADC - I'm not sure whether the sample
rate is 5GHz or 100 MHz.
Either way this is not important for my application, because I am not
thinking of the VCO as an ADC.

> you talk about the counter lsb as if this is somehow related to a very low
> sensitivity voltage and it isn't.
As explained above, a small change in the VCO frequency will be shown
as a change in the summed counter value.
The high digital resolution is because of the oversampling, and the
high analog resolution is because of the summing ( or averaging ).

I see it this way : the VCO is DC biassed to run at some frequency,
say 1GHz, with a very small AC modulation applied to it ( from the
antenna ).
say the VCO runs between 1,000,000 Hz and 1,000,001 Hz as the AC
signal changes ( a 1 part 10E9 change ).
You read the VCO's counter every 10 ns, so you would see a count of
0 , 10 , 20 , 30  at the low frequency , with a missed count every
10E9 counts at the higher frequency. Average this over 1 second and
you would see a change of 1 in the counter as the AC input changed
( 1,000,000 mod 2**18 or 1,000,001 mod 2** 18 ).
To express this in terms of ADC's, it is a 10 x oversampled 1 bit ADC,
averaged over 1 second.
This has sacrificed analog range - you measure only deltas, but I am
only interested in deltas.
Given that you can display the change of 1 count on a PC screen, this
means that you can detect a change on the input pin that causes a 1 in
10E9 change in frequency - this is the high analog sensitivity that I
hope to see.

The thing that makes the GA144 special is that the electrical circuit
between input pin and counter is the smallest it could be, so there
could be very small quantum effects that would probably not occur with
a conventional ADC setup.

> While it is waiting for the input transition it is "asleep".
I understand sleep mode in terms of chips like the MSP430, where the
system clock is slowed down or stopped, and it takes some time to get
it back to full speed.
In the case of the MSP430 the design has been cleverly optimised for
fast wake-up ( 6 us IIRC ).
Since the GA144 has no clock, it does not have a distinct sleep state,
and therefore it has no wake up time.

>> In my experience, it is best never to use ADC's, but to convert the
>> signal you want to measure into a time period.
> Oh, do you have lots of experience with this?
Yes - I have used time measurement in preference to voltage on many
projects.

> How does the GA144 measure time periods?
> I think Chuck does it by tying the ADC input to Vdd which will run the VCO at max rate.
Yes, that is my understanding too. Its just a fast counter. Is there
any other way to measure time periods?

> Notice that there is no input signal in this example.
> Where would you connect your input signal?
On a digital input of a neighbouring F18, so that it captures the VCO
counter when the input changes state.

> I thought you were interested in high resolution???  Now I'm very confused.
I am interested in high resolution measurement of electrical charge
flowing into the analog input pin.
I think all this talk about ADC specs is confusing in this context...

> I'm still confused, what is X again?
X is  " how can I use the GA144's VCO as a very high resolution ADC?"
Answer - you can't.
Y is  " how can I use the GA144's VCO to measure very small analog
changes on its input pin with very high resolution?" Answer - see
above.

I have found this thread very helpful, as it has forced me to organise
and express my thoughts about what I would like to do with the GA144.
Hopefully I will find some time soon to actually do these tests - I
will report any results here :-)

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16353

On 10/16/2012 7:12 AM, Howerd wrote:
> On Oct 15, 10:38 pm, rickman<gnu...@gmail.com>  wrote:
>
> Hi Rick,
>
>> If it fits in with existing theory, then it should be observable with existing technology.
> Yes, the GA144 is existing technology...

That is not sufficient.  There is a world of existing technology and 
some will do the job and some won't.  The point is... and I'm getting 
really tired of trying to make it, if the stuff you want to measure fits 
existing theory then the existing technology that also fits that theory 
should be capable of measuring it.  By existing technology I mean any 
ADC that has adequate resolution and speed.


>> you have said nothing understandable that indicates the GA144 will do anything any other ADC can't do.
> The GA144 is very simple, so the electrical path between input pin and
> counter output is very short.
> This might allow effects to be observed that would be smoothed out by
> amplifiers, filters and conventional ADCs.

But you don't have any idea that I can tell of what you are looking for. 
  You never answered my question about what two outcomes would show the 
existence or absence of the effect you want to measure.


>> You talk about 5 GHz as if it is the sample rate and it isn't,
> If you clock a counter at 5GHz +/-100MHz, as the frequency changes the
> value of bit 0 of the counter when observed every 10 ns will change,
> and this value, if summed over a long period of time, will reflect the
> change in frequency. Since this is a VCO a small change in voltage
> will cause a small change in frequency which will cause a change in
> the summed count value.

Why do you need to look at this one bit?  To detect the change in 
frequency over a long period you can just directly read the *entire* 
counter and subtract subsequent readings.  This value is directly 
proportional to the frequency.  The longer the period you monitor it the 
greater the analog resolution.  I'm not sure dealing with bit 0 the way 
you describe will even give you a meaningful value.  I believe you will 
simply be monitoring what amounts to aliasing.


> It depends on exactly how you define these terms, but you could view
> this as an oversampled 1 bit ADC - I'm not sure whether the sample
> rate is 5GHz or 100 MHz.

It's not.  The VCO won't run at 5 GHz unless your input voltage is very 
close to Vdd.


> Either way this is not important for my application, because I am not
> thinking of the VCO as an ADC.

I know, you aren't thinking of it as an ADC, but you are using it as an 
ADC.


>> you talk about the counter lsb as if this is somehow related to a very low
>> sensitivity voltage and it isn't.
> As explained above, a small change in the VCO frequency will be shown
> as a change in the summed counter value.

No, because the frequency shows up in the counter by taking the 
difference.


> The high digital resolution is because of the oversampling, and the
> high analog resolution is because of the summing ( or averaging ).

If you say so.


> I see it this way : the VCO is DC biassed to run at some frequency,
> say 1GHz, with a very small AC modulation applied to it ( from the
> antenna ).

Ok, now you are biasing the ADC input with the input superimposed.


> say the VCO runs between 1,000,000 Hz and 1,000,001 Hz as the AC
> signal changes ( a 1 part 10E9 change ).
> You read the VCO's counter every 10 ns, so you would see a count of
> 0 , 10 , 20 , 30  at the low frequency , with a missed count every
> 10E9 counts at the higher frequency. Average this over 1 second and
> you would see a change of 1 in the counter as the AC input changed
> ( 1,000,000 mod 2**18 or 1,000,001 mod 2** 18 ).

Ok, so now you are reading the entire counter, not just bit 0.  At the 
higher frequency you won't see a missed count, you will see a count of 
N+1.  This is how I am suggesting that you use the ADC as an ADC.  By 
"average" I assume you mean integrate or "sum"?  Average would loose 
data unless you use fractions and then it is really just the same as 
integrating with a wasteful division at the end.


> To express this in terms of ADC's, it is a 10 x oversampled 1 bit ADC,
> averaged over 1 second.

No, it is just the same ADC that is designed into the GA144 sampled very 
fast and then the differences added back together which is the same as 
just subtracting the first reading from the last.


> This has sacrificed analog range - you measure only deltas, but I am
> only interested in deltas.

That is how you use the ADC, take the delta of the counter readings. 
This gives you the integral of the voltage over the sample period.


> Given that you can display the change of 1 count on a PC screen, this
> means that you can detect a change on the input pin that causes a 1 in
> 10E9 change in frequency - this is the high analog sensitivity that I
> hope to see.

What voltage will result in the change of 1?  That depends on the period 
over which you integrate, it has nothing to do with the bias you apply. 
  In fact, if you look at the ADC input curve you will see that it is 
most sensitive at the mid range and by biasing it near Vdd you are in a 
very flat range with little sensitivity.


> The thing that makes the GA144 special is that the electrical circuit
> between input pin and counter is the smallest it could be, so there
> could be very small quantum effects that would probably not occur with
> a conventional ADC setup.

Please explain how these quantum effects will be observed?  What 
difference will this make on your readings?


>> While it is waiting for the input transition it is "asleep".
> I understand sleep mode in terms of chips like the MSP430, where the
> system clock is slowed down or stopped, and it takes some time to get
> it back to full speed.
> In the case of the MSP430 the design has been cleverly optimised for
> fast wake-up ( 6 us IIRC ).

Not 6 us, any processor can start up in 6 us if you keep the oscillator 
running or use gates for the oscillator.  The F18A stops to wait for an 
input and resumes in some time less than an instruction cycle.  They 
won't tell me how much of the port read instruction executes before the 
sleep and how much happens after the sleep.  But they tell me I am free 
to measure it for myself...


> Since the GA144 has no clock, it does not have a distinct sleep state,
> and therefore it has no wake up time.

That is your terminology.  Sleep means it is doing nothing and the 
processor is doing nothing while it is waiting for an input transition. 
  Call it a rose if that makes you feel better.


>>> In my experience, it is best never to use ADC's, but to convert the
>>> signal you want to measure into a time period.
>> Oh, do you have lots of experience with this?
> Yes - I have used time measurement in preference to voltage on many
> projects.
>
>> How does the GA144 measure time periods?
>> I think Chuck does it by tying the ADC input to Vdd which will run the VCO at max rate.
> Yes, that is my understanding too. Its just a fast counter. Is there
> any other way to measure time periods?
>
>> Notice that there is no input signal in this example.
>> Where would you connect your input signal?
> On a digital input of a neighbouring F18, so that it captures the VCO
> counter when the input changes state.

What is this input signal?  I thought we were talking about the antenna?


>> I thought you were interested in high resolution???  Now I'm very confused.
> I am interested in high resolution measurement of electrical charge
> flowing into the analog input pin.
> I think all this talk about ADC specs is confusing in this context...

No, what is confusing is that you won't talk about the ADC as an ADC. 
To measure electrical charge flowing (otherwise known as current) you 
need to add a resistor to turn the current into a voltage.  Then the ADC 
can measure the voltage.


>> I'm still confused, what is X again?
> X is  " how can I use the GA144's VCO as a very high resolution ADC?"
> Answer - you can't.
> Y is  " how can I use the GA144's VCO to measure very small analog
> changes on its input pin with very high resolution?" Answer - see
> above.

Ok, now I understand.  You don't want to measure voltage, charge *or* 
current, you want to measure ANALOG.  I can see why you don't want to 
use an ANALOG to DIGITAL converter to measure ANALOGs.  That would be 
pointless.   BTW, perhaps you should share with the Green Arrays people 
that their ADC can't measure with high resolution.  It will be news to 
them!!!


> I have found this thread very helpful, as it has forced me to organise
> and express my thoughts about what I would like to do with the GA144.
> Hopefully I will find some time soon to actually do these tests - I
> will report any results here :-)

Please keep us informed.  I am finding this very entertaining... sort of.

Rick

[toc] | [prev] | [next] | [standalone]

#16374

Hi Rick,

I've chopped the bulk of the reply post because it is getting way too
long...

>> X is  " how can I use the GA144's VCO as a very high resolution ADC?"
> BTW, perhaps you should share with the Green Arrays people
> that their ADC can't measure with high resolution.
No, you can't use the VCO as a VERY high resolution ADC ( 30 bits ).
But you can, I think, use it to measure down to this level if you use
the counter directly, and not as a conventional ADC.


> You don't want to measure voltage, charge *or* current, you want to measure ANALOG.
Exactly. Voltage and current are scalar quantities, quantum mechanics
shows that electric fields are vectors, so current flowing in a wire
is a 1 dimensional representation of a 2 or more dimensional field.
If you measure voltage with chips that are desinged to measure
voltage, you will only see voltage.
So, yes I want to measure ANALOG, whtever that is.

I will keep you informed of progress...

Best regards,
Howerd

[toc] | [prev] | [next] | [standalone]

#16398

On 10/17/2012 2:05 AM, Howerd wrote:
> Hi Rick,
>
> I've chopped the bulk of the reply post because it is getting way too
> long...
>
>>> X is  " how can I use the GA144's VCO as a very high resolution ADC?"
>> BTW, perhaps you should share with the Green Arrays people
>> that their ADC can't measure with high resolution.
> No, you can't use the VCO as a VERY high resolution ADC ( 30 bits ).
> But you can, I think, use it to measure down to this level if you use
> the counter directly, and not as a conventional ADC.

I think you need to read a bit more about the GA144 and how the ADC 
works.  There is no limit to the resolution of the ADC data word.  Once 
you actually understand how the ADC works, you will see that.  But as 
long as you keep talking about the constituent parts, you will not see it.


>> You don't want to measure voltage, charge *or* current, you want to measure ANALOG.
> Exactly. Voltage and current are scalar quantities, quantum mechanics
> shows that electric fields are vectors, so current flowing in a wire
> is a 1 dimensional representation of a 2 or more dimensional field.
> If you measure voltage with chips that are desinged to measure
> voltage, you will only see voltage.
> So, yes I want to measure ANALOG, whtever that is.

Hey, ANALOG is *your* term, not mine!  Go back to your previous post, 
you said, "Y is  " how can I use the GA144's VCO to measure very small 
analog changes on its input pin with very high resolution?" Answer - see
above."  So what is an ANALOG that you are measuring changes in?


Rick

[toc] | [prev] | [next] | [standalone]

Page 2 of 3 — ← Prev page 1 [2] 3  Next page →

Back to top | Article view | comp.lang.forth

csiph-web