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:
Aug. 02, 1977
Filed:
Sep. 19, 1975
Masashi Kanno, Katano, JA;
Sukeichi Miki, Ikoma, JA;
Tsuneo Takezaki, Neyagawa, JA;
Syuichi Ninomiya, Kadoma, JA;
Abstract
This invention provides an FM four channel stereo signal generator for generating from four stereophonically related audio signals an FM four channel stereo signal expressed by (S.sub.1 +S.sub.2 +S.sub.3 +S.sub.4) + (S.sub.1 +S.sub.2 -S.sub.3 -S.sub.4)sin.omega.t+(S.sub.1 -S.sub.2 -S.sub.3 +S.sub.4)cos.omega.t+pilot signals with or without (S.sub.1 -S.sub.2 +S.sub.3 -S.sub.4)sin2.omega.t. The generator includes a matrixing device for producing from the four audio signals four matrixed audio signals (aS.sub.1 +bS.sub.2 +bS.sub.3 +cS.sub.4), (bS.sub.1 +aS.sub.2 +CS.sub.3 +bS.sub.4), (bS.sub.1 +cS.sub.2 +aS.sub.3 +bS.sub.4) and (cS.sub.1 +bS.sub.2 bS.sub.3 +aS.sub.4), where 2b=a+c; a main gating circuit for producing from the audio or the matrixed audio signals a main gated signal including a four channel stereo signal and harmonics; and a subsidiary gating circuit for producing from the audio or the matrixed audio signals a subsidiary gated signal corresponding to a harmonic nearest the four channel stereo signal, whereby by combining the audio or the matrixed audio signals, the main and the subsidiary gated signals and the pilot signals, and by passing the thus combined signal through a low pass filter, the desired four channel stereo signal of high quality can be easily produced.