Demodulation of phase modulated fibre-optic sensor system signals

摘要

Demodulation apparatus for demodulating phase-modulated signals comprises a quadrature signal generator (QSG) for generating in-phase (I) and quadrature-phase (Q) signals in response to an unmodulated input signal. The QSG provides fast frequency tracking of the input signal and excludes any high-frequency content the input signal.