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:
Dec. 10, 1991
Filed:
Mar. 27, 1990
Masaru Kanazawa, Tokyo, JP;
Taiichiro Kurita, Tokyo, JP;
Kazuhiko Shibuya, Tokyo, JP;
Taiji Nishizawa, Tokyo, JP;
Yutaka Tanaka, Tokyo, JP;
Minoru Honda, Tokyo, JP;
Kazumasa Enami, Tokyo, JP;
Haruo Okuda, Tokyo, JP;
Hideki Suganami, Tokyo, JP;
Yoshiharu Hoshino, Tokyo, JP;
Toshiyuki Takegahara, Tokyo, JP;
Kaoru Watanabe, Tokyo, JP;
Nippon Hoso Kyokai, Tokyo, JP;
Abstract
A method and system for multiplexing additional audio information in the form of pulse code modulation (PCM) audio signals onto a television signal. The PCM audio signal is time multiplexed into scanning retrace intervals of the video signal. At a receiver, the bit error rate of the decoded PCM audio signal is compared with a threshold so as to switch the audio output from the PCM audio signal to a conventional FM demodulated audio signal when the bit error rate exceeds the predetermined threshold. In this way, the benefits of both PCM audio and FM audio can be obtained by utilizing the higher immunity of FM signals in low signal-to-noise ratio environments, while the high fidelity PCM audio signal is utilized when the signal-to-noise ratio environment is relatively high.