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:
Sep. 08, 1981
Filed:
Sep. 24, 1979
Takashi Okada, Yokohama, JP;
Yasunobu Kuniyoshi, Tokyo, JP;
Sony Corporation, Tokyo, JP;
Abstract
A filter circuit, preferably a low-pass filter, whose cut-off frequency is easily controlled and which can be manufactured as an integrated circuit. First and second transistors are connected in differential amplifier configuration, and a current source is connected to the common connection of the emitter electrodes thereof. The base electrode of the first transistor is connected to an input terminal. A reactance element is connected between the collector electrode of the second transistor and a source of reference potential, such as ground. A third transistor has its emitter electrode connected to the base electrode of the second transistor and its base electrode connected to the collector electrode of the second transistor. An output terminal is connected to the emitter electrode of the third transistor.