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:
May. 25, 1999
Filed:
Feb. 18, 1997
Applicant:
Inventor:
Donald R White, Beaverton, OR (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04B / ;
U.S. Cl.
CPC ...
370276 ; 379394 ; 379403 ;
Abstract
A full duplex communication circuit uses a transducer as both a microphone and speaker/earphone to provide full duplex communication without acoustical feedback. The circuit uses a novel amplifier configuration to apply a signal received from a remote source to the transducer without loading it. The output of the transducer has a combined transmit and receive signal. To eliminate feedback of the receive signal in the output of the transmit signal, an audio processing circuit (analog) takes this combined signal and simultaneously compresses the receive signal and expands the transmit signal to produce a transmit signal that is 35-40 dB greater than the receive signal at the output.