phase response in sweept bode blot

[Scott56789]

Hi, I would like to measure the frequency response (bode plot) of a real system using SignalExpress. I started looking at the "Simple Sweet Measurement" example file, but didn't see how to obtain a phase response.  That example only shows the magnitude gain. 

I also tried recording the input and response, and then playing back through a frequency response step, but this didn't work because the frequency response analyzes each block, not the entire recorded signal.

Any suggestions?  

Maybe the tone-extraction step?

I am using the USB-6229 for reference.

[dansch]

Hi Scott,

In the case of sweeping frequency that way, it appears that you are correct in that using the Tone Extraction step (under Analysis » Frequency-Domain Measurements) should work for obtaining the detected phase of the signal. You can display this value on a chart and it will update through each iteration of the frequency sweep. I was able to successfully setup a sweep by outputting a sine wave on my PCI-6251 ao0 channel and reading the signal back on my ai1 channel (using a ~3" wire). For each frequency in the sweep, I charted the  phase response and amplitude. As you can see in the attached screenshot, the amplitude remained the same and the phase decreased linearly. Please let me know if this is the kind of information you are trying to retrieve from your signal. I have also attached the SE Project I used as reference.

Regards,