FM Stereo Demodulator (Using a Phase Locked Loop) U.S. Patent 3,714,595Engineering Faculty Publications
AbstractAn FM stereo demodulator uses a phase locked loop to synchronize a 76 kHz oscillator with a received 19 kHz pilot. A two stage binary frequency divider is coupled in cascade with the oscillator to provide a symmetrical 38 kHz waveform for carrier reinsertion and a 19 kHz waveform for phase comparison. The received pilot is coupled to a phase detector in the phase locked loop through a high pass filter formed of passive components. A pilot detector uses EXCLUSIVE OR gates coupled to the frequency divider to develop a 19 kHz waveform in phase with the pilot for phase comparison with the received composite signal to determine the presence of the received pilot.
Published CitationDenenberg; Jeffrey N. , Padgett; William J., FM Stereo Demodulator (Using a Phase Locked Loop) U.S. Patent 3,714,595 issued January, 1973
Citation InformationJeffrey N. Denenberg and William J. Padgett. "FM Stereo Demodulator (Using a Phase Locked Loop) U.S. Patent 3,714,595" (1973)
Available at: http://works.bepress.com/jeffrey_denenberg/3/