Why doesn't the Demodulation FSK right?

[christopherriche]

Have a nice day I have received a signal that the FSK modulation has been used according to the received spectrum. I modulated it using GNU software, but it is strange that it does not start with Preamble. Does anyone know what is happening?Input SignalFiltered SignalSpectrum SignalDemod Signal

[christopherriche]

Can it be synchronous or non-synchronous?
What about coherence and noncoherence?

[christopherriche]

I don't know for sure, but I think it's non-synchronous and noncoherence.

[Cartwright94]

I have received a signal that the FSK modulation has been used according to the received spectrum.

I modulated it using GNU Radio, but it is strange that it does not start with Preamble. Does anyone know what is happening?

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