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:
Apr. 14, 1981
Filed:
Aug. 16, 1979
Applicant:
Inventor:
Eijiro Tamura, Tokyo, JP;
Assignee:
Trio Kabushiki Kaisha, Tokyo, JP;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
H03F / ; H03G / ;
U.S. Cl.
CPC ...
330109 ; 179 / ; 330294 ; 330304 ; 333 / ;
Abstract
A tone control circuit including an operational amplifier having (a) an input circuit or output circuit and (b) a feedback circuit where circuits (a) and (b) are symmetrically disposed with respect to a reference potential such as ground. Circuitry is also provided to compensate for load and/or feedback impedances. Further, circuitry is provided to reduce the number of switches and capacitors needed to vary the high and low cut-off frequencies of the tone control circuit.