How to measure Voltage vs Frequency

[Pradeesh]

I want to measure the voltage vs Frequency from the Piezoelectric crystal. In Labview, I took time vs voltage and frequency vs voltage, but the voltage in both graphs are not the same. USB 6009 DAQ is used to measure. Myself I want to extract the voltage vs Frequency data in excel. please help me to do this. I have attached the VI file.

Thanks,

[Henrik_Volkers]

Depending on the signal there are different ways..

The fourier transformation is the common way to do it. It will give you the amplitudes and phase of the signal components (depending on window type and size). The help and a book or lecture on signal theory can explain that in more detail. (For example, if you use power spectrum.vi the amplitudes (except DC) is scaled with 1/SQRT(2) 😉 )

If you have sine excitation a sine fit or the (FFT based) extract tone information.vi give a more precise information.

Keep in mind that the 6009 has a quite low input impedance. So unless you use an external signal conditioner (best would be a charge amplifier for piezo electric devices), that (and the cable capacity) will have an influence on the transfer function

[Pradeesh]

Thanks. . .