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. 24, 1983
Filed:
Apr. 15, 1981
Applicant:
Inventor:
Jimmy Tow, Holmdel, NJ (US);
Assignee:
Bell Telephone Laboratories, Incorporated, Murray Hill, NJ (US);
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H04M / ;
U.S. Cl.
CPC ...
179 / ; 324 / ;
Abstract
In a multifrequency receiver, a threshold level (VTH) supplied to a group of threshold comparators (105-1 through 105-N) is controllably adjustable by a variable threshold generation circuit (104) in response to received multifrequency signals. As the envelope of the received multifrequency signal experiences a positive amplitude transition, the threshold level is increased at a fast rate (fast attack). Also, as the envelope of the received multifrequency signal exhibits a negative amplitude transition, the threshold level is decreased at a much slower rate (slow release).