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. 23, 1990
Filed:
Apr. 10, 1989
Errol R Williams, Austin, TX (US);
VideoTelecom Corp., Austin, TX (US);
Abstract
Disclosed is an adaptive Finite Impulse Response ('FIR') filter speakerphone that provides improved echo cancelation by the inclusion of a tracking comb filter having nulls which change to track the voice portion of communications. The speakerphone also includes a pair of ambient noise recorders for recording both ambient background noise received from the telephone line and ambient background noise in the signal to be transmitted to the telephone line. During intervals of low signal level, pre-recorded ambient noise is substituted for the communication signals. The speakerphone also controls the respective strengths of the received and transmitted signals during intervals when voice signals are present. A delay buffer adapts the speakerphone for use in videoconferencing.