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:
Mar. 25, 1980
Filed:
Feb. 14, 1978
Koichi Sakai, Tokyo, JP;
Satoru Horie, Tokyo, JP;
Shinji Kitahara, Kauwasaki, JP;
Kozo Suzuki, Tokyo, JP;
Toko, Inc., Tokyo, JP;
Abstract
In a noise cancelling system for FM receivers, means is provided whereby a pilot signal of 19 KHz is always detected from a stereo composite signal, whether or not a noise canceller circuit is operated. The 19 KHz pilot signal is injected into a phase locked loop, and a signal of 38 KHz in synchronism with the 19 KHz pilot signal is generated which in turn is injected into the multiplex demodulation circuit. Furthermore, means may also be provided which eliminates, from the 19 KHz pilot signal, noise mixed into the stereo composite signal and having a frequency characteristic of (19/n) KHz (n=1, 2, . . .) and then detects the foregoing pilot signal, thereby achieving satisfactory stereophonic separation.