FM Demodulator PLL with compensation for nonlinear varactor characteristics

摘要

There is provided an improvement of an FM demodulator of the PLL system including a VCO, a phase comparator and a low-pass filter, whereby the distortion components of the FM demodulated signal to be caused due to nonlinearity of the frequency vs. control voltage characteristic of the VCO are eliminated. This improved FM demodulator of the PLL system includes a circuit for making the harmonic distortion components from the output signal of the low-pass filter and synthesizing them with the output signal of the low-pass filter so as to obtain the non-distorted FM demodulated signal.