NI 6552 Signal Express sampling rate

[Deee-Lite]

I am generating several signals for Signal Express. When I execute them, some work well and some don't, that is, for some signals the sampling rate changes!!! Thera are two options in Signal Express: 1. to read the sampling rate from waveform file 2. to set manually the sampling rate. In both cases the rate is changed when I run the waveform, from my 90MHz to 100MHz. 

Any ideas?

[JuanCarlos · Accepted solution]

Hi,

The internal clock on the 6552 is generated from 200MHz timebase; that is you can generate frequency of 200MHz/N where N goes from 2 to a large number that takes it down to 47 Hz. The driver for the board will coerce to the neerest value, so if you sweep frequency from 90Mhz to 100MHz, you will get 100MHz in all cases. There is some more information about timing on the specs here:

http://digital.ni.com/manuals.nsf/websearch/E4C93B141B71ED93862573CC005E8EA1

Ounce you run your project, Signal Express should show you the corced value, you can use this to read the actual generated frequency. 

I hope this helps.

Juan Carlos