Victor Company of Japan, Limited

Katsuhiro Ohba

Nobuaki Takahashi

Yasuo Itoh

Shinji Nakamura

Yoshiki Iwasaki

Kazunori Nishikawa

Yasuhisa Okabe

Masaaki Satoh

Hideaki Ozaki

Nobuaki Suda

Tatsuo Sawada

Nobuhide Ohsaki

Fujio Suzuki

An angle modulated wave demodulation system demodulates an input angle modulated wave by means of a phase locked loop system which comprises a phase comparator, which is operated responsive to an input angle modulated wave. A voltage controlled oscillator is supplied with a part of the output of the phase comparator which controls its oscillation frequency. The oscillator supplies its oscillation frequency to the phase comparator. The phase locked loop system has a lock frequency range which decreases its width when the level of the input angle modulated wave is below a predetermined level. The portion of this lock range in which the width of the lock range decreases is positively utilized. The voltage controlled oscillator oscillates at a frequency equal to the center frequency of the carrier of the input angle modulated wave, when the phase locked loop becomes unlocked.

Angle modulated wave demodulation system

A multichannel record disc reproducing system comprises at least two phase-locked loops. Each loop includes a phase comparator and a voltage-controlled oscillator for respectively demodulating an angle-modulated signal which is separated from a signal picked up from a multichannel record disc. The picked up signal includes a direct-wave signal and an angle-modulated signal which were multiplexed and recorded. An addition circuit adds the demodulated output signals of the phase-locked loops. The respective phase-locked loops have different lock ranges in order to exclude noise and other distortion.

Multichannel record disc reproducing system

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Yokohama, Japan

Katsuhiro Ohba