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. 11, 1984
Filed:
Apr. 13, 1982
Hitoshi Hirata, Tokyo, JP;
Pioneer Electronic Corporation, Tokyo, JP;
Abstract
An AM detector circuit capable of performing an AGC function having a wide dynamic range and low level of distortion and spurious interference. A first differential amplifier receives an amplitude-modulated signal to be detected as differential inputs. Outputs of the first differential amplifier are connected as constant current source inputs to second and third differential amplifiers. The differential inputs of the second and third differential amplifiers are fed with a signal synchronous with the carrier wave of the amplitude-modulated signal. Outputs of the second and third differential amplifiers are interconnected to provide multiplication outputs representing the product of the amplitude-modulated signal and its carrier wave. The detector AM signal is passed through a low-pass filter and then through a fourth differential amplifier to a current mirror circuit. The current mirror circuit feeds parallel-connected transistors of opposite conductivity types connected across the differential input of the first differential amplifier to provide the AGC function.