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:
Sep. 03, 1991

Filed:

Sep. 28, 1989
Applicant:
Inventor:

Masayuki Iwamatsu, Hamamatsu, JP;

Assignee:

Yamaha Corporation, Hamamatsu, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03G / ;
U.S. Cl.
CPC ...
381107 ; 381109 ;
Abstract

An input level adjusting circuit used for an input source switching section in an audio device such as a control amplifier comprises an input selector for selecting one of input signals from plural input sources and outputting the selected signal and also outputting information concerning the selected input signal, a level adjusting circuit connected to this input selector for adjusting the level of the selected input signal, a memory for prestoring input level setting offset amounts which are relative differences in an amount of level adjustment for the plural input sources, and a control circuit responsive to the information concerning the selected input signal applied from the input selector for reading out one of the input level setting offset amounts for the corresponding input source and controlling the level adjusting circuit in accordance with the read out input level setting offset amount. The level adjusting circuit is automatically controlled in response to the selection of the input source to adjust the level of the input signal and thereby maintain a constant output level regardless of difference in the input level.


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