FM demodulation with IQ method

[frozenduck2]

I am currently doing a project which requires me to demodulate a FM signal, given I samples and Q samples. I can then compute the arctangent and determine the phase, but I have no idea what to do with the phases and how I can use them in the program. I read about it on the internet, but those algorithms involved I and Q being functions, not points.

It'd be great if anyone could help me out!

[JGoebel]

I haven't worked with demodulation for a while, so I can't explain the exact concept of demodulating it. But you need more then just one sample to demodulate. You need to get the frequencies and you can't detect frequency from a single sample.

You should consider using an array and a shift register, to append the samples to a package with specific length (the longer, the more precise your measurement will be).

Then you process a package of signal only every e.g. 512th iteration.

I hope this is not supposed to run with a live incoming radiosignal? I would guess that labview and the pc are both too slow for that.

[RTSLVU]

Here is example on using I/Q to demodulate FM without needing any special LabVIEW tool kits.

SDRLab: an RTL-SDR interface to LabVIEW for educational purposes