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:
Nov. 05, 1991
Filed:
Mar. 30, 1990
Shouji Uehara, Konosu, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
A system for level-compressing a sync signal component of a video intermediate frequency signal to scramble the signal. A compression pulse generation circuit generates a compression pulse in synchronism with a sync signal. A level compression circuit level compresses the sync signal component of the video intermediate frequency signal in response to the compression pulse. A sine wave generation circuit generates a sine wave having a frequency n times that of the sync signal in synchronism with the sync signal. A control data generation circuit generates control data for controlling a phase of the sine wave and generates a sine wave phase-controlled in accordance with the control data. A superposing circuit superposes the phase-controlled sine wave on an audio intermediate frequency signal and outputs a superposed signal. An output circuit outputs the level-compressed signal and the audio intermediate frequency signal. A detector detects the superposed signal and extracts the sine wave. A compression position detector detects a compression position and outputs a detection signal. An expansion pulse generation circuit generates an expansion pulse on the basis of the sine wave and the detection signal. A level expansion circuit expands the sync signal component in response to the expansion pulse.