Is comm.FMDemodulator a product detection method?

I looked at the algorithm of comm.FMDemodulator, and I have a question: comm.FMDemodulator does not require the input of the carrier frequency (fc). So how does it perform the step ys(t)=Y(t)e−j2πfcty_s(t) = Y(t) e^{-j 2\pi f_c t}ys​(t)=Y(t)e−j2πfc​t? Or is it using another method, such as phase demodulation?

Answer 1

[Mike McLernon]

The comm.FMDemodulator object processes input signals at complex baseband, as do nearly all of the functions and objects in Communications Toolbox. As such, the carrier frequency is explicitly not modeled.

Also, the object performs a phase differencing operation across each pair of received samples, then scales that difference by the sample time to arrive at frequency.