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:
Oct. 17, 1995
Filed:
Nov. 22, 1994
Yutaka Tomiyori, Tokyo, JP;
Tadashi Eguchi, Saitama, JP;
NEC Corporation, Tokyo, JP;
Abstract
Controlled by a signal level produced by a microphone (12), a noise suppressing circuit (25) supplies a first attenuator (16) with a local level which is equal to the signal level and is suppressed to a predetermined output level when the signal level is lower and higher than a predetermined input level. Cooperating with a drive level produced by a second attenuator (17) to drive a loudspeaker (13), the local level makes a comparator unit (21-23) produce a control signal for making the first attenuator give smaller and greater amounts of attenuation to the signal level with the drive level rendered by the second attenuator low and high when positive and negative values are had, respectively, by an input difference equal to the local level less the drive level. Preferably, the local level is suppressed by a level difference had by the signal level above the predetermined input level.