FM multipath noise reduction circuit

Claim 1

An FM multipath noise reduction circuit, comprising; a charge/discharge circuit having an output, and having an input to which is applied an S meter voltage which corresponds to a received electric field intensity and which is outputted by an intermediate frequency amplification stage in an FM stereo receiver; a first condenser having first and second ends, said first end being connected to said charge/discharge circuit; charge/discharge control circuit means for detecting in said S meter voltage an alternating current voltage corresponding to multipath noise and for causing said charge/discharge circuit to respectively discharge and charge said first condenser in response to detection of the presence and absence, respectively, of said alternating current voltage, said charge/disicharge circuit producing at said output thereof a control voltage having a value which varies as a function of the amount of charge on said first condenser; a second condenser for rapid charging which has two ends respectively connected to a power source and said first end of said first condenser, said power source further being connected to and supplying power to said charge/discharge circuit and said charge/discharge control circuit means; and control means for controlling signal separation of the FM demodulation in said FM stereo receiver as a function of said control voltage from said output of said charge/discharge circuit.