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:
Jul. 17, 1984
Filed:
Aug. 23, 1982
Ralph N Battista, Colts Neck, NJ (US);
Quentin D Groves, Berkeley Heights, NJ (US);
Jimmy Tow, Holmdel, NJ (US);
AT&T Bell Laboratories, Murray Hill, NJ (US);
Abstract
A tone receiver suitable for use in a telephone system and which adaptively narrows its amplitude sensitivity range defining valid tone signals on a per call basis in accordance with the amplitude of a first tone signal received on a call. The signal range adaptability improves signal echo rejection and spurious noise talkoff. A preferred embodiment is implemented by a programmed digital signal processor which increases the lower amplitude signal threshold in accordance with the amplitude of the first signal. An alternative embodiment adaptively attenuates the level of incoming signals before signal validation. A further improvement of both embodiments allows further amplitude range narrowing in response to any subsequent signal on a call which has an amplitude greater than that of any preceding signal in the call.