Analog Discovery Pitfall

[blueskull]

I just got my analog discovery delivered today. I hooked it up, and did some experiments.

It seems the AWG has a pitfall in its square wave and square-saw wave functions.

The jitter is extremely high, and it is not random. The jitter is extremely stable, to be precisely, 10nS.

I double checked this output using either the integrated scope channel and my VDS3102 USB scope. The results are the same.

I suspect the problem comes from the DDS module, and I think all AWG can not directly (without comparator) generate precision square wave.

Am I right? Or if there are any other reasons?

[tggzzz]

It has a 100MHz clock = 10ns (not nS).

If you want a 99MHz clock you will have to use a DDS to generate a sine wave, use an analogue filter that to remove harmonics, then use a comparator to regenerate a square wave. See, for example the ad9851 for how to do that.