[SI-LIST] Re: signal source distribution and jitter question
- From: C Deibele <deibele@xxxxxxx>
- To: Paul Levin <levinpa@xxxxxxxxxxxxx>,Si-List Si-List <si-list@xxxxxxxxxxxxx>
- Date: Fri, 15 Nov 2002 10:07:33 -0500
Paul,
I need all the freqs at the same time.
5 psec jitter means that if one examines the rising edge of a particular source
and examines the rising edge of any other source in the same distribution, one
will
not see the riding edge move by more than a certain amount.
In essence, I am interested in the RMS jitter, but that implies that that the
peak
to peak jitter is also under control.
For example, I measured the jitter of some commercial sources using a TEK scope
using
several techniques. This showed me that some extra frequency spectrum leaked
through
and this caused circa 50% of the jitter!
This topic is really a mix of SI and of good oscillator design...so I was
hoping someone
had to tackle this problem.
The only way I can solve this problem with a commercial oscillator is at the
high frequency
end -- here I measure less than a picosecond of jitter. In phase, this shows a
0.5 degrees
of RMS jitter. Which is about accurate to 0.3%.
At the low end, Cypris makes a good chip that can do about 5 psecs...which is
tolerable.
I am just curious if anything else is out there that I might try.
Thanks,
Craig
Paul Levin wrote:
> Dear Craig,
>
> Do you need all of these frequencies at the same time, or just a few of
> them at any given time? What do you mean by 5 psec jitter? RMS? Peak-
> to-peak, and if so, at what probability? The answer probably lies in
> voltage controlled oscillators and phase-locked loops. By the way, how
> good a sinewave do you need?
>
> Regards,
>
> Paul
> _____________________
>
> C Deibele wrote:
>
>> Hi,
>>
>> I have a problem to solve, and am looking for a few pointers to help.
>>
>> I need to generate several frequencies and keep them locked together.
>> The frequencies need to be stable -- which is to say to keep the jitter
>> of each signal minimally low...on the order of a fraction of a
>> picosecond.
>>
>> The frequencies I need to generate are the following:
>> 2.5 MHz,
>> 50 MHz,
>> 350 MHz,
>> 400 MHz,
>> 750 MHz, &
>> 800 MHz.
>>
>> I need sinusoids. I am nervous about the rather tight constraints on
>> the jitter. Most of the parts I've used are circa 5 psecs of jitter.
>> Does anyone have any pointers or perhaps a special part that can
>> handle this constraint?
>>
>> thanks,
>>
>> Craig Deibele
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