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:
Jun. 26, 1984
Filed:
Oct. 05, 1981
Hitachi, Ltd., Tokyo, JP;
Abstract
A time-constant circuit suitable for being fabricated into an integrated circuit comprising a resistive element with its one end connected to a first input terminal, an impedance converting circuit with its input connected to another end of said resistive element and its output connected to an output terminal, a variable gain differential amplifier with its one input connected to the output of said impedance converting circuit and its another input connected to a second input terminal, an adder circuit for adding an output from said amplifier and an input signal appearing on said second input terminal, and a capacitive element connected between the junction of said resistive element and said impedance converting circuit and the output of said adder circuit. A plurality of the time-constant circuits are combined to construct a filter circuit. The gain of the variable gain differential amplifier in each time-constant circuit is controlled by a common DC voltage, whereby the spread of characteristic values of the integrated circuit elements can be compensated.