Is there any method to measure random jitter without TimePod or scopes costing
a small fortune?
.md
> On 9 Jan 2022, at 01:21, Bruce Griffiths <[email protected]> wrote:
>
> Yes, that post is full of misleading information.
> The TI document is irrelevant as the PIC based divider doesn't have non
> harmonically related signals using the same chip.
> All internal signals within the PIC are harmonics of the divided output
> signal.
> The post did not distinguish between random jitter and data dependent jitter
> etc. Either the poster doesn't understand the finer details of frequency
> division or the post is intended to mislead.
>
> Bruce
>> On 09/01/2022 12:55 Angus via time-nuts <[email protected]> wrote:
>>
>>
>> Maybe it got mashed up, but I only linked to one post, and that
>> addressed the specific question that had been asked. There is also, as
>> far as I know, no 'misinformation' in it. However if anything does
>> need corrected, I can easily do that.
>>
>> One of the main reasons that I did the test was all the actual
>> (IMHO...) misinformation that was in the thread about the PIC
>> dividers. I find them very useful and have not had any problems with
>> them, but since they are mostly used on 53131As which do not have a
>> very high resolution, I also wanted to see if I was missing anything.
>>
>> As far as I can see, it showed just what is going on as well as I
>> could have expected with that scope, os I don't quite agree that
>> *everything* should be ignored :)
>>
>> Angus.
>>
>>
>> On Sat, 8 Jan 2022 14:00:28 +1300 (NZDT), you wrote:
>>
>>> That entire thread is full of misinformation and should be ignored unless
>>> one understands the difference between random and data dependent jitter.
>>>
>>> For a well designed divider with a single output frequency only the random
>>> jitter spec is significant.
>>>
>>> One doesn't need a bunch of expensive LeCroy gear to measure RJ of such
>>> dividers as its PN manifestations are readily apparent and measurable.
>>>
>>> Using one of the supposedly super low jitter flipflops isn't a panacea. In
>>> practice unless an appropriately designed ZCD is used the wideband input
>>> noise of the very fast FF will dominate and produce much more jitter than
>>> expected due to the relatively slow slew rate of the outputs of most 10MHz
>>> sources.
>>>
>>> Bruce
>>>
>>>> On 08/01/2022 12:40 Angus via time-nuts <[email protected]> wrote:
>>>>
>>>>
>>>> On Fri, 07 Jan 2022 12:40:49 -0800, you wrote:
>>>>
>>>>>> The two biggest outside influences on the PICDIV are supply voltage and
>>>>>> temperature.
>>>>>
>>>>> Another interesting influence is the number of outputs that are switching
>>>>> and
>>>>> the load on them. In particular, if you have several outputs running at
>>>>> different frequencies, the clock-out delay should be slightly longer when
>>>>> 2
>>>>> outputs switch when compared to when only one is switching.
>>>>>
>>>>> Has anybody measured that on a PIC? (or similar chip)
>>>>>
>>>>> I think one of tvb's picDEVs has several outputs.
>>>>
>>>> To some extent:
>>>> https://www.eevblog.com/forum/projects/easiest-way-to-divide-10mhz-to-1mhz/msg3257018/#msg3257018
>>>> _______________________________________________
>>>> time-nuts mailing list -- [email protected] -- To unsubscribe send
>>>> an email to [email protected]
>>>> To unsubscribe, go to and follow the instructions there.
>> _______________________________________________
>> time-nuts mailing list -- [email protected] -- To unsubscribe send an
>> email to [email protected]
>> To unsubscribe, go to and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- [email protected] -- To unsubscribe send an
> email to [email protected]
> To unsubscribe, go to and follow the instructions there.
_______________________________________________
time-nuts mailing list -- [email protected] -- To unsubscribe send an
email to [email protected]
To unsubscribe, go to and follow the instructions there.
