CPM timing recovery


#1

hey all,

I am trying to demodulate a CPM (for now I’m doing it with 4-CPFSK
signal
with Raised Cosine pusle shaping) signal without knowing the symbol rate
(
i.e. the samples per symbol). does anyone know if this is possible?
Papers
that I have read on timing recovery for CPM assume that the symbol
period is
known.

thanks,

David


#2

Since the signal will not really have infinite bandwidth (instantaneous
transitions from one state to the next), the envelope will not be of
constant modulus. The signal will be amplitude modulated with a
component due to the data transitions. Looking at the modulus or
modulus squared will reveal a line in the fft due to this amplitude
modulation.

Bob

David S. wrote:

David



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