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:
Feb. 13, 1990
Filed:
Sep. 07, 1988
Masatoshi Tanaka, Fukaya, JP;
Wataru Kuroiwa, Fukaya, JP;
Akinori Masuko, Fukaya, JP;
Jyoji Maeda, Fukaya, JP;
Shouji Uehara, Konosu, JP;
Tsutomu Uekusa, Konosu, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A transmitter encoder has a gain selector for compressing the level of a horizontal sync signal component of a video intermediate frequency (IF) signal to scramble it, and an AM modulation degree controller for superposing a control signal, which indicates the timing for the level compression, on an FM audio IF signal in the form of AM modulation. The transmitter encoder further has an oscillator circuit for generating a sine wave with a horizontal frequency (fH) and an nfH sine wave having a frequency n times the horizontal frequency, and a mixer for mixing these sine waves to thereby provide the above control signal. A receiver decoder has an AM detector for detecting an AM component of the FM audio IF signal from the transmitter encoder to reproduce a composite signal and band filters for respectively extracting the fH and nfH sine waves from the reproduced composite signal. The receiver decoder further has a gain selector for expanding the compressed level of the horizontal sync signal component of the video IF signal from the transmitter encoder, by means of a sync expansion pulse generated on the basis of the fH sine wave.