Re: ball-hours

From	Joerg <news@analogconsultants.com>
Newsgroups	sci.electronics.design, comp.lang.forth
Subject	Re: ball-hours
Date	2014-10-16 13:37 -0700
Message-ID	<caaokmF457jU1@mid.individual.net> (permalink)
References	(6 earlier) <m1ml2f$u9o$1@dont-email.me> <ca8da5FfvlmU1@mid.individual.net> <m1nbn1$pu7$1@dont-email.me> <caagkuF1v4jU1@mid.individual.net> <m1p626$nu5$1@dont-email.me>

Cross-posted to 2 groups.

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rickman wrote:
> On 10/16/2014 2:21 PM, Joerg wrote:
>> rickman wrote:
>>> On 10/15/2014 7:12 PM, Joerg wrote:
>>>> rickman wrote:
>>>>> On 10/15/2014 8:36 AM, Joerg wrote:
>>>>>> Problem is, there is no Forth community out here. The last die-hard
>>>>>> Forth aficionado I personally met was about 30 years ago in Europe.
>>>>>
>>>>> I think you may be surprised.  I've already heard from three
>>>>> programmers
>>>>> from the few posts I've made in just three groups.  Unless you want me
>>>>> to send then directly to you, I am referring them to this thread.
>>>>>
>>>>
>>>> One of them contacted me already. They are sort of local but not really
>>>> local-local, like in the same village, down the road from here. We will
>>>> have lots of situations such as "Hey, I got stuck with the test rig,
>>>> can
>>>> you come over real quick?" or "The relief valve over yonder blew a
>>>> gasket, can you replace it?".
>>>
>>> So why aren't you working in the same lab?  Then it can be like,
>>> "Watson, come here.  I want you".
>>>
>>
>> Because as mentioned before if both are consultants it creates
>> confidentiality issues. I have only one room (office plus lab) and
>> another one mostly used for library and parts storage but not
>> acoustically shielded. I often have to hop on GoTo or some other service
>> to discuss another client's issue and then I must be alone. Sometimes
>> for 1-2h. In contrast to contractors who work one longer assignment at a
>> time I always have half a dozen or more active clients.
>>
>>
>>> BTW, if you heard from Charley Shattuck, he is a prominent Forth
>>> programmer.  He is working with a startup that developed a Forth like
>>> CPU with 144 processors with a peak rate of 700 MIPS each.  This chip
>>> includes 5 ADC and 5 DAC on chip with variable resolution (trade off
>>> between speed and resolution, about 15 bits at 48 ksps).  You might talk
>>> to him about the GA144, it might suit your needs.  It's main limitation
>>> is each processor has little memory and the I/O is limited.  But I don't
>>> think you will run out of MIPS.  lol
>>>
>>
>> Yes, had an email exchange with Charley.
>>
>> 144 processors with 700MIPS each would probably require us to also build
>> a nuclear power station :-) ... just kidding, I know it's green.
> 
> Each processor is very low power when running flat out, just 5 mW.  But
> they almost never run flat out.  Because they are asynchronous they
> spend most of their time stopped when they draw 0.0875 uW, yes, that's
> less than a tenth of a uW for each processor or just 12 uW for the whole
> chip.  The processors respond to stimuli in just nanoseconds, not 100's
> or even 10' but single digit nanoseconds.
> 
> Trust me, power will not be a problem with this part.  It is a very
> different beast to program however.
> 

I wonder how that company is doing. I read about their products years
ago but never seen any in schematics and I get to see a lot of new stuff
because some of my daily bread is EMC remedy.

> 
>>>>>                                     ... Your other post seemed to be
>>>>> talking about bitbanging the I2S port to the CODEC.  How does that
>>>>> work
>>>>> into the 100 MHz need?  Bitbanging a serial port of any kind can be
>>>>> CPU
>>>>> cycle intensive.
>>>>>
>>>>
>>>> Yes, it is a major concern. We might need to hang an FPGA in there at
>>>> least for TX, as a buffer, because essentially we are writing sine
>>>> waves. Doesn't work on RX though, that's time-varying stuff. I hope I2S
>>>> works for us, somehow. Got to find out.
>>>
>>> ???
>>>
>>
>> Well, to send out sine waves. No need to necessarily bother a processor
>> with that. Or I use a DDS but that can cost in clock synchronicity.
> 
> Every problem in your design is asking for an FPGA.
> 

Possible, but not sure yet. Maybe there is a bigger processor out there
with real I2S/TDM and enough support by the manufacturer.


> 
>>> What are the specs you need from the ADC?  Do you have numbers and such?
>>>   I think you mentioned a low drift with temperature.  The GA144 would
>>> need to be compensated for temperature, but has lots of processing to do
>>> that.  :)
>>>
>>
>> Five needed in total, 18bits or more, 48ksps, differential inputs, BW
>> from DC to 15kHz, without phase jitter issues. DC-Offset can be handled
>> via mux and SW-clamping as long as it won't jitter or drift around much.
> 
> "phase jitter issues" and "won't jitter or drift around much" aren't
> specs. 


What I mean is that ADCs on processors generally cannot hold jitter low
enough to truly deliver a 96dB SNR. I found that even 12 bits on-chip is
already a serious challenge.


 18 bits of what exactly?  I have seen lots of devices with 24
> bits but only 96 dB SNR.  Do you need 108 dB SNR?  You won't get that
> from the GA144 ADCs at 48 kHz.
> 

True 96dB across DC-15kHz would be enough.

-- 
Regards, Joerg

http://www.analogconsultants.com/

Thread

Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 00:25 -0400
  Re: ball-hours bruce.person@gmail.com - 2014-10-14 23:51 -0700
    Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 03:15 -0400
  Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-15 05:36 -0700
    Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 16:22 -0400
      Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-15 16:12 -0700
        Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-15 22:48 -0400
          Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 11:21 -0700
            Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 15:24 -0400
              Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 13:37 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 17:42 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 07:14 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 14:03 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 12:03 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 15:23 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 12:44 -0700
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 18:37 -0400
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 20:59 -0400
                Re: ball-hours albert@spenarnc.xs4all.nl (Albert van der Horst) - 2014-10-17 08:43 +0000
                Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-17 13:53 -0400
                Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-17 07:50 -0700
        Re: ball-hours Raimond Dragomir <raimond.dragomir@gmail.com> - 2014-10-15 20:42 -0700
          Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 01:50 -0400
            Re: ball-hours Raimond Dragomir <raimond.dragomir@gmail.com> - 2014-10-16 00:49 -0700
              Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 05:14 -0400
            Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 11:58 -0700
        Re: ball-hours "Elizabeth D. Rather" <erather@forth.com> - 2014-10-16 08:32 -1000
          Re: ball-hours rickman <gnuarm@gmail.com> - 2014-10-16 15:32 -0400
          Re: ball-hours Joerg <news@analogconsultants.com> - 2014-10-16 13:45 -0700

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