Elimination of crosstalk between FM:FDM signal channels - with compensation signal derived from frequency demodulator input and subtracted from its output

摘要

The circuit arrangement is to eliminate crosstalk between frequency modulated and frequency division multiplex channels, and includes an FM-demodulator (1), connected to the first input (5) of a differential amplifier (2). An amplitude modulator (3) and linlinear filter (4) are connected to the other input. The cross-talk is generated by unwanted conversion of amplitude into frequency modulation and appears at the output of a frequency demodulator. A compensation signal is subtracted from the output signal of the FM demodulator. It is generated from the input signal of the FM demodulator by an amplitude demodulator with quadratic logarithmic characteristics and a following linear filter.