The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 15, 1980
Filed:
Jul. 14, 1978
Yukinobu Ishigaki, Yokohama, JP;
Teruo Muraoka, Yokohama, JP;
Masaki Hagihara, Yokohama, JP;
Takeo Nasu, Yokohama, JP;
Kunihiro Kato, Yokohama, JP;
Victor Company of Japan, Limited, Yokohama, JP;
Abstract
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.