[time-nuts] Divider pecking order ?

[Bruce Griffiths]

The performance of the sine to square wave conversion clock shaper 
circuit may dominate the divider performance.
Thus an evaluation of the jitter performance of sine to square wave 
conversion circuits would also be informative/useful.

If one is using a digital divider in a narrow band PLL the close in 
phase noise performance of the divider may be more important than its 
phase noise floor, in which case an ECL or CML divider (or at least a 
divider using a CML or ECL resynchronising flipflop) may be a better 
choice than a TTL or CMOS divider, especially if a low noise diode mixer 
is used as a phase detector is used.

Thus characterising divider phase noise may also be useful, although it 
may be difficult to do this for divider output frequencies much below 
1Mhz or so.

Bruce

Tom Van Baak wrote:
>> Group,
>>
>> If Dave P's current divider design has design jitter specs approaching
>> SOTA vvs cost levels whilst the TAPR board is (perhaps) slightly
>> inferior in performance, where does that leave Tom's venerable 1pps PIC
>> divider in the pecking order ?
>>
>> Will all designs be subjected to a "back-to-back" run-off sometime soon
>> ?  This would save us mere mortals without the means of verifying actual
>> jitter performance much angst and gnashing of teeth !
>>
>> Good work chaps.
>>
>> Kit
>> VK2LL
>
> Hi Kit,
>
> My guess is all of the dividers are more than good enough. But...
>
> Since the question of jitter comes up now and then, and since
> there are several new dividers in the queue this year, I thought
> I'd settle it once and for all and actually measure as many as I
> can find.
>
> An added bonus is that Magnus is able and willing to do the same
> and that means not only can we compare divider jitter but we can
> compare methods to measure divider jitter. In this field validating
> and comparing methods is as important as making measurements.
>
> As for pecking order? I don't really know yet. Wait to see if
> Peter picks a peck of pulsing picosecond PICs.
>
> /tvb
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>