FM Stereo Demodulator (Using a Phase Locked Loop) U.S. Patent 3,714,595

Jeffrey N. Denenberg, William J. Padgett

Research output: Contribution to journalArticlepeer-review

Abstract

An 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.

Original languageAmerican English
JournalDefault journal
StatePublished - Jan 1 1973

Disciplines

  • Engineering

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