[sdiy] jitter analysis

[Czech Martin]

I enjoyed the measurement whatsoever.
At least somebody did something!



If the jitter is expected to arrise from low frequency
modulation, this should be easy to verify by audio sampling
and looking at the spectrum.

I think it is not the question if 1us or 2us jitter
are audible on a single oscillator. The question is
how does it behave with two or more giving interesting beating
pattern.

The high frequency jitter (if audible at all) will apear as noise.
I think no one would like to have hissing noise riding on the
oscillator output. The interesting stuff is low frequency
jitter, maybe caused by 1/f noise.
See thread about noise and super-beta transistors.

If the low frequency jitter translates into a nice
frequency shift, it *will* be audible.
It is easy to hear frequency variations of 0.1% or even less.
When multiple oscillators are used this is even more true.


The problem with the given method seems to me, that the spectrum
is not available. Thus the cause of the jitter is not easy to determine.

Perhaps I think it over again.
And perhaps, if low frequency "noise" matters, why shouldn't this
be investigated with 44100 1/s sampling rate?


I think: time to go the other way: produce perfect waveforms and then add
random patterns of different spectral shapes to it. Of course,
not in the sense of just adding noise, but e.g. shifting the "Comparator"
threshold.


m.c.

> -----Original Message-----
> From: owner-synth-diy at dropmix.xs4all.nl
> [mailto:owner-synth-diy at dropmix.xs4all.nl]On Behalf Of Carole 
> Anne Scott
> Sent: Donnerstag, 8. Juli 2004 01:58
> To: Fredrik Carlqvist; synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] jitter analysis
> 
> 
> Hi Fredrik,
> There is a simple power supply modification ( 2 capacitors) 
> that can be
> performed on the ARP Odyssey.
> I believe that it will help cut the jitter.
> Is there any way that you can get the odyssey in your hands again?
> -Dana
> 
> 
> 
> Subject: [sdiy] jitter analysis
> Hello all!
> I am proud to announce that some of the oscillator jitter 
> measurements are
> complete! You can find it on
> http://www.minod.com/jitter/jitter.html
> Complete with pictures of distributions! The following VCOs has been
> measured:
> ARP Odyssey
> 
> 
> 
>