fir filter for fsk demodulator

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so the next step is just to implement this kind of filter with altera megafunction (fir compiler) for example or with simulink and test the reponse of iq demod?

Thanks again

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yes provided your IQ demod centres signal correctly by multiplying by relevant frequency.

The filter here is meant to remove the second copy(not noise, though it helps noise reduction).

once filtered you are left with a signal containing periods of f0/f1 then you can work out a way to convert them to zero and one possibly from gradient of phase.