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:
Mar. 03, 1981
Filed:
Aug. 08, 1979
Tetsuya Takizawa, Yamato, JP;
Viva Co., Ltd., Noda, JP;
Abstract
An automatic volume adjusting apparatus comprises a volume adjusting device connected between a sound signal source and a loudspeaker; a first rectifier circuit for generating a first signal having a D.C. level corresponding to the level of a sound signal supplied from the colume adjusting device to the loudspeaker; a microphone and a second rectifier circuit for generating a second signal having a D.C. level corresponding to the level of a composite sound constituted by the sound generated by the loudspeaker and the ambient noise; a subtraction circuit for generating a third signal having a level corresponding to the level difference between the first and second signals, i.e. the level of the ambient noise; a gate circuit for sampling the third signal at predetermined intervals; and an integrator circuit for holding the output of the gate circuit for a predetermined period of time. The output of the integrator circuit controls the volume adjusting device.