Abstract: An FM receiver having a phase-locked loop demodulator and a control voltage correction circuit for the local tuning oscillator. The correction circuit includes a comparator for comparing the output frequency of the phase-locked loop demodulator with the output signal from a reference oscillator, the output of the comparator being connected through an integrator to provide a control signal for the local oscillator as part of an automatic frequency control loop. The comparator output is also fed through an integrator to an adder connected between the demodulator output and the demodulator oscillator controlled input, for setting the demodulator oscillator at the center intermediate frequency when no carrier signal is being received.

Abstract: Phase or frequency demodulator comprising an automatic gain control circuit (100), a phase-locked loop (200) and, optionally, a shaping circuit (300) for shaping the output signal of the loop. A feedback path is provided between the output of the loop, or of the signal-shaping circuit, and the automatic gain control circuit, via an automatic noise control circuit (400) for producing an analog signal, the amplitude of which is proportional to the rate at which the loop is temporarily disabled.