How to get rid of the periodical spikes on the sinwave voltage output from NI USB 6251

[memorysun]

Hi Expert,

I am writing a program in Labview, aiming to generate a sum voltage signal (a ramp voltage plus a sin wave voltage) from NI USB 6251.

In the program, I could get clean signals, but when I check the voltage signals with scopes (three different scopes), the sin signals are corrupted by periodic spikes (40 KHz, 25 us) all the time. Then I unplugged the DAQ from the computer, checked the output from the DAQ, the spikes are still there.. So I think the spikes must come from the DAQ. How to get rid of them?

Thanks very much!

[will_i._am.]

Hello Memorysun,

In most Analog output applications (DAC tasks) glitches (spikes) are generated. There are techniques to reduce the  glitching which are outlined in this link http://digital.ni.com/public.nsf/allkb/9B13E25B0B0EC197862562B4007D2E33?OpenDocument. For glitch free tasks, you would need a dedicated Analog output card. Please refer to the usb 6251 manual below for the glitch energy information

http://www.ni.com/pdf/manuals/371291h.pdf 

Regards

Will

[will_i._am.]

Hello Memorysun,

I hope all is well. Can you please confirm if my previous post sheds more light on the problem and answers the question

Regards

Will

[Henrik_Volkers]

Just found:

Use an RC filter to 'deglitch' a DAC  Bonnie Baker, Texas Instruments -- EDN, July 28, 2011