phase noise or jitter analysis

[BenGilbert]

Hello,
Does anybody know how to perform an analysis on a captured analog signal (such as acquired by a data acquisition card) that results either in a measurement of phase noise or phase jitter.

Regards,

Ben Gilbert

[EBL]

Hi, Ben.

I've written phase noise measurement algorithms for a number of NI data acquisition cards. Conceptually it's fairly simple, but the implementation turns out to be complicated, as it involves a digital downconverter, either in hardware or host software.

Is there a particular board you'd like to use? Depending on the model, I may have some example code already written, or I may be able to cobble something together fairly easily.

EBL

[Yi Y]

Hi Ben,
There's not a VI that readily output what you are looking for, however, there are analysis VIs we can make use to achieve it. Exactly what kind of analysis are you trying to do for phase jitter? Absolute jitter, period jitter, or cycle to cycle jitter? What about phase noise? Do you have a reference signal?  Please specify what your set up is, what you have to work with and what you are trying to achieve.  Thanks!

Yi Y.
Applications Engineer
National Instruments
http://www.ni.com/support

[BenGilbert]

Hi EBL, I will be using the PCI-6529. Any example code would be great! Thanks, Ben

[BenGilbert]

Hi Yi, I am trying to get a measurement of jitter on a digital signal. I am not particular about the type of jitter measurement, I only need some sort of measurement. I do not have a reference signal. The reason I asked about phase noise measurements is that I know that it is possible to calculate the jitter from the phase noise. I cannot tell you much more than that at this stage because my application is commercially sensitive. Thanks, ben

[EBL]

Hmmm. The 6529 is a very slow (but very high-voltage-tolerant) digital interface card. I don't believe you'll be able to measure either jitter or phase noise with it. In any case I have no software that will apply to it.

If you can elaborate a little bit about the signal you're trying to measure without giving away too much, I might be able to recommend a more appropriate acquisition card.

Ed L.

[EBL]

Ben,

Is it possible you meant a PCI-6259? It might be usable for some jitter or phase noise measurements, although a low-pass filter would almost certainly be required.

Ed L.

[BenGilbert]

Yes, I am using the PCI-6259 not the PCI-6529 Thanks, Ben

[EBL]

Well, apologies, Ben. It doesn't look like I have any code that will work for that family of boards. Perhaps in the future I'll be able to modify some code to work with it.

Be advised that if you want to make phase noise measurements with this board, you'll have to have a very good anti-aliasing filter to remove harmonics of your fundamental which might otherwise alias and show up as jitter.

Ed L.