US Patent 11290761 Detection of CPD from signals captured at remote PHY device

A method of detecting CPD in an HFC network that includes a remote PHY device (RPD) is disclosed. The RPD includes a transmitter, receiver, and diplexer having forward and return legs. The receiver receives a return signal from a cable plant via the return leg. The transmitter provides a forward signal to the cable plant via the forward leg. A portion of the forward signal leaks through the return leg and travels to the receiver. The return signal contains a CPD signal generated by the forward signal and a CPD source in the cable plant. The forward signal propagates from RPD to CPD source and CPD signal propagates from CPD source to RPD within a round-trip interval. The method comprises: (a) adjusting the capturing bandwidth of the receiver to include return and leaked forward signals; (b) operating receiver to capture return and leaked forward signals over a limited duration of at least the round-trip interval; and (c) detecting CPD signal by processing captured leaked forward and return signals.