09-20-2012 02:44 PM
Hi.
I am generating a chirp signal using MathScript node and plotting it's PSD. Then I am passing the signal to DAQ (X Series) acquiring it on an analog input and plotting its PSD again. Both times I am using the same "Spectral Mesurements" VI to calculate the PSD. I am not using any windows or averaging and both results are in dB. I am also plotting the time domain signals. As expected, the time domain signals look exactly the same, and the PSD looks the same except for the Y scale. So, I am trying to understand where the difference in the Y scale is comming from.
I am attaching the screenshot and the VI
Thanks a lot for any help.
09-21-2012 06:55 PM
I took a look at your attached VI, one suggestion I have for you is to wire the "Stimulus" to a Convert From Dynamic Data VI before wiring it to the Signals input of the Spectral Measurments 3 express VI. Just to see if data type has any effect on the PSD of the signals.
-Jake B.
09-26-2012 09:31 AM
Thank you, I will try that.