[plonter]

is there a way that i can measure the jitter coming out from my dac?
is there a special device for that or something...?
another question is, what term is used to describe jitter amount?

thanks!

 

[royalcrown]

As far as I know, you need an oscilloscope to measure jitter. Also, again AFAIK, jitter is represented in some form of seconds (I think picoseconds).

 

[plonter]

Quote:

Originally Posted by royalcrown /img/forum/go_quote.gif As far as I know, you need an oscilloscope to measure jitter. Also, again AFAIK, jitter is represented in some form of seconds (I think picoseconds).

thanks. is this oscilloscope is hard to get? i guess they don't sell it in local audio stores.

 

[Nerull]

Unless you're very serious about digital design (not even considering audio at this point), it's not worth it. It's expensive to find a decent scope for this task. This also goes without saying that you'll have to be particularly well voiced in high-speed stuff (RF). There are some other techniques that don't use an oscilloscope (spectrum analyzer or counter), but those too, require test rigs and quite a bit of knowledge of RF.

Here's a baseline for understanding jitter:
http://www.tek.com/Measurement/scope...5W_16146_1.pdf

Some techniques to measuring it can be found here:
http://www.hparchive.com/seminar_not...easurement.pdf

Needless to say, this isn't a walk in the park. A lot of audio websites oversimplify this and post dubious measurements to support their product. They can though, because most don't have the equipment to measure this stuff, let alone know what the measurements actually mean for them.

You can also measure the noise of the oscillator (>100Hz region) and come up with a relatively good idea on how your oscillator is performing.
Here is a low-noise amp specifically for that purpose:
http://www.wenzel.com/pdffiles1/pdfs/lowamp.pdf

I can understand your need to want to do this, but it's quite an endeavor.

~Thomas

 

[plonter]

thanks for the info. i think i am gonna pass this though. too much trouble indeed. i will probably have to ignore the jitter issue for a while and hope that my dac clean most of it. thanks anyway.