Multistage phase demodulation system - has filter converting phase modulation into frequency modulation whose amplitude indicates phase

摘要

The phase demodulation system has a filter with a specified amplitude/frequency response and arranged so that a frequency modulated signal is derived from the received phase modulated signal from whose amplitude the phase modulation can be obtained directly. The filter consists of a number of stages. One stage is passive low-pass filter whilst the other active high-pass filters. The advantage lies in avoiding large amount of l.f. noise produced in systems that are noticeably sensitive to frequencies lying below the threshold frequency.