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. 16, 1981
Filed:
Nov. 13, 1979
Yoshihiro Kawanabe, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
A signal change-over amplifier for an FM receiver for switching over between AM and FM receiving modes without the addition of frequency response distortion or pop noise. The amplifier circuit includes two input signal control sections each of which includes a differential transistor pair. Activating current is fed to the emitters of the differential transistor pairs by a constant current source which is activated in response to the input control signal. The collectors of the transistor of the two input control sections are interconnected. The base of one transistor of one pair is coupled to the base of the corresponding transistor of the other pair. The input information-bearing signals are coupled to the bases of the other transistors in the two pairs. The interconnected collectors are coupled respectively to a transistor pair in an output section to which current is fed by a current mirror circuit. The final output is provided by a push-pull circuit. Feedback is provided between the output section and the two input sections through a resistor pair coupled between the output terminal of the push-pull pair and the interconnected bases of the input signal control sections.