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:
Jan. 05, 1993

Filed:

Nov. 26, 1991
Applicant:
Inventors:

Hiroshi Kondo, Tsurugashima, JP;

Hiroshi Tanigawa, Tsurugashima, JP;

Tsuneo Tohyama, Tsurugashima, JP;

Isao Fukai, Tsurugashima, JP;

Assignee:

Toko, Inc., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03B / ; H03K / ;
U.S. Cl.
CPC ...
307520 ; 328167 ; 330294 ; 330107 ;
Abstract

An active filter circuit comprises a differentiator constituted by an operational amplifier having an input terminal and output terminal, and a first integrator constituted by a first capacitor and a first variable conductance amplifier for providing negative feedback to the operational amplifier and a first variable conductance amplifier; and a second integrator constituted by a second capacitor and a second variable conductance amplifier for providing negative feedback to the first integrator. The active filter circuit is arranged such that a damping pole is set up at a predetermined frequency by adjusting operating currents of the first and second variable conductance amplifiers.


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