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Re: VCO IC needed 5-35MHz

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  Re: VCO IC needed 5-35MHz rgo.else@gmail.com - 2016-05-26 18:05 -0700
    Re: VCO IC needed 5-35MHz Jon Elson <elson@pico-systems.com> - 2016-05-26 22:00 -0500
      Re: VCO IC needed 5-35MHz colonel_hack@yahoo.com - 2016-05-26 22:48 -0700
        Re: VCO IC needed 5-35MHz Michael Black <et472@ncf.ca> - 2016-05-29 19:03 -0400
          Re: VCO IC needed 5-35MHz legg <legg@nospam.magma.ca> - 2016-05-30 12:27 -0500
      Re: VCO IC needed 5-35MHz Brian Gregory <bvdvgvrvevgvovrvy@gmail.com> - 2016-06-03 02:57 +0100

#5976 — Re: VCO IC needed 5-35MHz

On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
> Anybody recommend a VCO IC that will tune 5-35MHz. Square wave output is
> OK.
> 
> --
> Neil
> http://www.aade.com
> mailto:neil@aade.com
> Almost All Digital Electronics
> 1412 Elm St. SE
> Auburn, WA 98092
> 253-351-9316

Hi if u want 0 to 32mhz in 1 hz steps

clock 24bit counter at 64mhz feed into 24bit comparater use the 64mhz clock (modules avaliable). For bit 1 use the clock directly.This forms count to x. then feed output into bi-stable this halfs frequecy to 32mhz and gives u 50:50 duty cycle. 3x 74ac521 8 bit comparators could be used not a=b outs fed into a 74ac10 3 input nand this would generate MR for 2 x 74hc4040 by philips which are garanteed to 79mhz clk. with the 3 x 8bit latchs for the count to x value should fit on a 100 by 100 pcb which u can get 5off made out in china for 10usd.

Good luck and regards Roger G1BFK

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#5977

rgo.else@gmail.com wrote:

> On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
>> Anybody recommend a VCO IC that will tune 5-35MHz. Square wave output is
>> OK.
>> 
>> --
>> Neil
>> http://www.aade.com
>> mailto:neil@aade.com
>> Almost All Digital Electronics
>> 1412 Elm St. SE
>> Auburn, WA 98092
>> 253-351-9316
> 
> Hi if u want 0 to 32mhz in 1 hz steps
> 
> clock 24bit counter at 64mhz feed into 24bit comparater use the 64mhz
> clock (modules avaliable). For bit 1 use the clock directly.This forms
> count to x. then feed output into bi-stable this halfs frequecy to 32mhz
> and gives u 50:50 duty cycle. 3x 74ac521 8 bit comparators could be used
> not a=b outs fed into a 74ac10 3 input nand this would generate MR for 2 x
> 74hc4040 by philips which are garanteed to 79mhz clk. with the 3 x 8bit
> latchs for the count to x value should fit on a 100 by 100 pcb which u can
> get 5off made out in china for 10usd.
Yes, a DDS is the way to go, as long as a little phase noise is acceptable.
But, you won't be able to build this with 74ACxx parts, no way they will 
clock at 64 MHz.  I don't know where you found this 79 MHz spec, I see 24 
MHz, but note that the 4040 is not a synchronous counter, it is a ripple-
carry chain, so the total delay through the string of FFs is 30 ns PER 
STAGE, so 360 ns!  So, there is no way to decode this as a count, as it will 
have a time skew of about one clock time every time one of the FFs toggles.

Jon

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#5978

On Thu, 26 May 2016, Jon Elson wrote:

> rgo.else@gmail.com wrote:
>
>> On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
                           ^^^^

Idiots.

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#5979

On Thu, 26 May 2016, colonel_hack@yahoo.com wrote:

> On Thu, 26 May 2016, Jon Elson wrote:
>
>> rgo.else@gmail.com wrote:
>> 
>>> On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
>                          ^^^^
>
> Idiots.
>
>
I've seen replies to old posts like this, and it can get a lot worse.

Someone asking about Linux, whatever the reason someone replies to an old 
post in the first place, once the thread has been resurrected, someone's 
bound to say "you're using an outrageously old version of Linux, you 
should upgrade immediately".  Indeed, the problem might not be there if 
the poster was able to use a later version of Linux, but it was cutting 
edge back then.

The real trick is to be able to ask the future a question, and get an 
answer back in the past. Then someone fussing with this back in 1999 could 
just wait, and now the solutions are quite different from back in 1999.

   Michael

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#5980

On Sun, 29 May 2016 19:03:20 -0400, Michael Black <et472@ncf.ca>
wrote:

>On Thu, 26 May 2016, colonel_hack@yahoo.com wrote:
>
>> On Thu, 26 May 2016, Jon Elson wrote:
>>
>>> rgo.else@gmail.com wrote:
>>> 
>>>> On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
>>                          ^^^^
>>
>> Idiots.
>>
>>
>I've seen replies to old posts like this, and it can get a lot worse.
>
>Someone asking about Linux, whatever the reason someone replies to an old 
>post in the first place, once the thread has been resurrected, someone's 
>bound to say "you're using an outrageously old version of Linux, you 
>should upgrade immediately".  Indeed, the problem might not be there if 
>the poster was able to use a later version of Linux, but it was cutting 
>edge back then.
>
>The real trick is to be able to ask the future a question, and get an 
>answer back in the past. Then someone fussing with this back in 1999 could 
>just wait, and now the solutions are quite different from back in 1999.
>
>   Michael

I wouldn't discount the usefulness of advice like this, in a
repair-type forum, provided the whole thread is presented and not
'snipped'. These tend to be searched by people who aren't interested
in chatting, but are just trying to fix something that is similarly
outdated.

Knowing that a problem existed, and how it was solved in 1999, may be
more relevent than any you-tube video made since...

A lot of traffic is lifted whole by people trying to bulk up
non-usenet vehicles, often with dates subverted.

but yeah....check the date

RL

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#5988

On 27/05/2016 04:00, Jon Elson wrote:
> rgo.else@gmail.com wrote:
>
>> On Sunday, October 31, 1999 at 7:00:00 AM UTC, neil wrote:
>>> Anybody recommend a VCO IC that will tune 5-35MHz. Square wave output is
>>> OK.
>>>
>>> --
>>> Neil
>>> http://www.aade.com
>>> mailto:neil@aade.com
>>> Almost All Digital Electronics
>>> 1412 Elm St. SE
>>> Auburn, WA 98092
>>> 253-351-9316
>>
>> Hi if u want 0 to 32mhz in 1 hz steps
>>
>> clock 24bit counter at 64mhz feed into 24bit comparater use the 64mhz
>> clock (modules avaliable). For bit 1 use the clock directly.This forms
>> count to x. then feed output into bi-stable this halfs frequecy to 32mhz
>> and gives u 50:50 duty cycle. 3x 74ac521 8 bit comparators could be used
>> not a=b outs fed into a 74ac10 3 input nand this would generate MR for 2 x
>> 74hc4040 by philips which are garanteed to 79mhz clk. with the 3 x 8bit
>> latchs for the count to x value should fit on a 100 by 100 pcb which u can
>> get 5off made out in china for 10usd.
> Yes, a DDS is the way to go, as long as a little phase noise is acceptable.
> But, you won't be able to build this with 74ACxx parts, no way they will
> clock at 64 MHz.  I don't know where you found this 79 MHz spec, I see 24
> MHz, but note that the 4040 is not a synchronous counter, it is a ripple-
> carry chain, so the total delay through the string of FFs is 30 ns PER
> STAGE, so 360 ns!  So, there is no way to decode this as a count, as it will
> have a time skew of about one clock time every time one of the FFs toggles.
>
> Jon
>

He said VCO - Voltage Controlled Oscillator.
And he said it over 16 years ago.

-- 

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

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