Method and apparatus for measuring the instantaneous frequency of FM signals

摘要

A method and an apparatus for measuring the instantaneous frequency of FM modulated signals, comprises a sampling means, an instantaneous frequency computing means and a lowpass filtering means. The sampling means samples FM modulated signal at prescribed intervals to provide digitized FM signal. The instantaneous frequency computing means manipulates the digitized FM signal mathematically using a new mathematical equation proposed in this invention to provide the instantaneous frequency based on digitized FM signal samples. More accurate instantaneous frequency values can be obtained by filtering the computed instantaneous frequency values using a lowpass filter.