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:
Sep. 20, 1988
Filed:
Jun. 16, 1986
Applicant:
Inventors:
Alan C Busche, Dorchester, CA;
Beverley W Gumb, London, CA;
Assignee:
Northern Telecom Limited, Montreal, CA;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
379433 ; 381189 ; 381169 ;
Abstract
A telephone handset for use in noisy locations has a noise cancelling electret transmitter which receives a normal acoustic input at the front end and a background noise acoustic input to the rear end. The input to the rear end is via a grill on the back side of the handset. A dielectric shield is positioned between the grill and the transmitter. A resistor is inserted in series with the transmitter to reduce the sensitivity and produce a lower than normal transmit level. Also, a filter is used to reduce the level of high frequency emphasis.