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FM Demodulation with De-Emphasis

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?

 

 

 

 

 

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Message 1 of 4
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Hey,

 

Have you tried using the VIs in the Signal Processing palette of LabVIEW?

Michael Bilyk
Former NI Software Engineer (IT)
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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.

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Thanks for posting your solution.

 

Cheers

Michael Bilyk
Former NI Software Engineer (IT)
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