[SI-LIST] Re: Jitter transfer vs. accumulation

Vinu
I would agree, and would claim that the RMS value is a scalar 
representation of an unbounded phenomena (the 1-sigma value of the 
statistics), when we view it w.r.t. a true Gaussian distribution.  The 
jitter itself is unbounded.

I suspect that we have a nomenclature issue.  I would claim, however, 
that the measured RMS jitter value (not the actual) will change over 
time as additional samples are taken, and better statistical confidence 
is obtained.  The RMS jitter value is then a bounded number which 
describes an unbounded process.

But I'm just a hack engineer. WTF do I know?


Scott

Scott McMorrow
Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
(401) 284-1827 Business
(401) 284-1840 Fax

http://www.teraspeed.com

Teraspeed® is the registered service mark of
Teraspeed Consulting Group LLC



Vinu Arumugham wrote:
> May be we need to clear up the terminology/definitions.
>
> By RMS jitter I think George is referring to RJ rms or the 1-sigma 
> value of the gaussian. This I think is bounded as George has 
> repeatedly stated.
> The peak-peak RJ of course is unbounded and depends on the number of 
> samples. I think George has referred to this as phase jitter.
>
> Comments from Steve and Alfred seemed to suggest that the RJ rms, the 
> 1-sigma of the gaussian itself is unbounded.
> Steve, Alfred could you please clarify if that is what you meant/observe?
>
> Thanks,
> Vinu
>
>
>
> Scott McMorrow wrote:
>> George
>>
>> I have a quick question.  You said:
>>
>> "The VCO RMS jitter is bounded, and so is the PLL RMS jitter.  The RJ
>> distribution takes on a true Gaussian waveform."
>>
>> My meager understanding of this is that Rj is by definition unbounded. And 
>> the presence of a true Gaussian distribution (when all other deterministic 
>> components have been subtracted out) is an indication of this unboundedness. 
>> And yes, theoretically it will approach infinity at infinite time. However, 
>> because the random component is so low, it "seems" to be bounded within a 
>> specific BER confidence level.  Which is why we have repeatability in 
>> measurements.  My contention is that Rj is much smaller than most people 
>> believe or are able to measure, and that it is low probability deterministic 
>> noise components that dominate the jitter spectrum. Unfortunately, these can 
>> also tend to have near-gaussian distributions, mucking up the measurement 
>> apparatus.
>>
>> If what I say above is correct, then what you describe above is truly 
>> unbounded jitter, taking on a Gaussian distribution.
>>
>> Do you agree?
>>
>>
>> best regards,
>>
>> Scott
>>
>>
>>
>>
>> Scott McMorrow
>> Teraspeed Consulting Group LLC
>> 121 North River Drive
>> Narragansett, RI 02882
>> (401) 284-1827 Business
>> (401) 284-1840 Fax
>>
>> http://www.teraspeed.com
>>
>> Teraspeed® is the registered service mark of
>> Teraspeed Consulting Group LLC
>>
>>
>>   
>>>   
>>>     
>> ------------------------------------------------------------------
>> To unsubscribe from si-list:
>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>> or to administer your membership from a web page, go to:
>> http://www.freelists.org/webpage/si-list
>>
>> For help:
>> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>
>> List technical documents are available at:
>>                 http://www.si-list.net
>>
>> List archives are viewable at:     
>>              http://www.freelists.org/archives/si-list
>> or at our remote archives:
>>              http://groups.yahoo.com/group/si-list/messages
>> Old (prior to June 6, 2001) list archives are viewable at:
>>              http://www.qsl.net/wb6tpu
>>   
>>
>>   
>


------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field

or to administer your membership from a web page, go to:
http://www.freelists.org/webpage/si-list

For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field


List technical documents are available at:
                http://www.si-list.net

List archives are viewable at:     
                http://www.freelists.org/archives/si-list
or at our remote archives:
                http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: