06-21-2018 05:22 PM
I am using a PXI-5661 Vector Signal Analyzer with LabVIEW 2014 and the NI Modulation Toolkit to demodulate FM broadcast-quality voice. I need to apply a de-emphasis filter on the received signal to compensate for the pre-emphasis placed on the audio signal by the transmitter. The MT Demodulate FM.vi does not appear to provide de-emphasis functionality. How can I de-emphasize the received audio using the above configuration?
06-22-2018 04:04 PM
Hey,
Have you tried using the VIs in the Signal Processing palette of LabVIEW?
06-29-2018 09:19 AM
I'm aware of the Signal Processing pallet, but I was unsure how to implement the filter. The de-emphasis filter I needed should be a low-pass filter with a time constant of 75uSec (in the US). The filter should provide 6dB/octave of attenuation above the cutoff frequency. it turns out that a 1st order Butterworth low pass filter fits the bill.
This post was helpful:
https://forums.ni.com/t5/LabVIEW/6-dB-octave-highpass-Butterworth-problem/td-p/2862100
Thanks for your reply.
06-29-2018 09:52 AM
Thanks for posting your solution.
Cheers