[time-nuts] Oh dear

[Bob Camp]

Hi

Be careful when you talk about jitter of any device, OCXO's included. There
is always an implied bandwidth in the conversion of phase noise to jitter.
If you extend the bandwidth down low enough (as in low audio) the jitter
goes up quite a bit. In the case of audio, jitter at low frequencies just
might be something to worry about.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of Attila Kinali
Sent: Monday, May 07, 2012 12:19 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Oh dear

On Mon, 7 May 2012 10:02:25 -0600
Tom Knox <actast at hotmail.com> wrote:

> 
> Actually the numbers are quite real, play with the math, a small amount
> of jitter in a DAC (X) can have a large difference (Y) when sampling a
> complex wave form especially in the audiophile world where the sound of
> 24bit dac 16,777,216 discrete levels is clearly superior to older
> 16 bit dac 65,536 possible levels in 44.1 KHz to 192 KHz formats.  

Yes, i know that jitter is a pain when it comes to ADCs, but keep
in mind that your audio ADC does have a jitter of a couple
100ps itself. If it's a high end ADC that is. The standard ADCs are usually
in the ns range. For a normal 10MHz XO you measure the jitter in in the
lower
10ps at most, a good one at lower than 1ps cycle-to-cycle. Of course, you
have
to keep the clock signal clean of any disturbance that might add modulations
to it. But that's a matter of keeping the power supply clean and having the
signal shielded. It's not an inherent property of an Rb to have low jitter.
And as we all know from the recent  hype on the FE-5860As and the
following measurements, not all Rb's are low jitter.

			Attila Kinali

-- 
Why does it take years to find the answers to
the questions one should have asked long ago?

_______________________________________________
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.