I have a circuit which has been designed by System Generator to be implemented on FPGA. The circuit’s output is a CPM (Continuous Phase Modulation) signal in which it is apparent that its instantaneous frequency is changeable. I should transmit the data via UART and RS232 to see it on a computer.
However, it has the problem that, in high frequencies, the Nyquist criterion has been violated and hence in high frequency I have not a nice sinusoidal signal. I think that for resolving this issue I should relate the start of UART to the frequency of output signal. Now I wonder:
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How should I measure the instantaneous frequency of CPM signal?
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In other words, how should I measure it in System Generator?