Victor Company of Japan, Limited

Takeo Nasu

Yukinobu Ishigaki

Teruo Muraoka

Kunihiro Kato

Masaki Hagihara

A phase tracked loop frequency demodulator having a phase comparator receptive of a frequency modulated signal and a peak-shifting filter for imparting a constant phase shift of 90.degree. over the full range of its instantaneous frequencies in response to a feedback control signal to permit the phase comparator to compare the non-phase shifted and phase shifted signals. The carrier frequency components of the output from the comparator are eliminated by means of a second filter to derive a demodulated signal which is used as the control signal. In order to eliminate high frequency limitations of the peak-shifting filter, this filter is comprised of a variable reactance element and a complementary reactance element so connected thereto to form a resonant circuit which possesses a quadratic frequency response characteristic with a resonant peak at the upper or lower frequency end of the passband.

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Yokohama, Japan

Takeo Nasu