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.

Date of Patent:
May. 13, 1986

Filed:

Jan. 04, 1984
Applicant:
Inventors:

Joichi Sato, Atsugi, JP;

Ryuji Shiono, Machida, JP;

Tsutomu Niimura, Hiratsuka, JP;

Toshiaki Isogawa, Atsugi, JP;

Mitsuru Sato, Atsugi, JP;

Assignee:

Sony Corporation, Tokyo, JP;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04N / ; H04N / ; H04N / ;
U.S. Cl.
CPC ...
358164 ; 358169 ; 358 32 ;
Abstract

A circuit having a nonlinear response characteristic provides gamma compensation to a video luminance signal and matches any desired output response curve by selecting the number of diodes connected as series-connected circuits in the compensation circuit. The relationship among the various numbers of series-connected diodes is dependent upon having a current flowing into an output circuit which is the same as a current flowing out of a collector circuit of a differential amplifier, to which the input video luminance signal is applied, and through series-connected diode circuit. These currents are maintained equal by use of a current-mirror circuit, which provides an input current to an output transistor that has in its emitter circuit one of the series-connected diode circuits, and the compensated luminance signal flows in the collector circuit thereof. The differential amplifier is stabilized and balanced by a difference amplifier connected in feedback across the collector leads of the differential amplifier in conjunction with a pedestal clamping synchronization signal and a capacitor to provide a balancing signal at the base lead of the second transistor of the differential transistor amplifier.


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