Study on processing of multi-carrier phase-modulated signals from a laser heterodyne intrusion detecting system

Introduced a intrusion detecting system based on laser heterodyne interference technique. Analyzed the features of the multi-carrier phase-modulated signals from the detecting system, signal demodulation purpose and technical requirements are discussed, proposed the intrusion event judgment method by power spectrum analysis and realized the intrusion signal extraction by means of phase-lock-loop technique. Moreover, analyzed several issues affecting system performance and corresponding solutions are proposed.