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. 14, 1991
Filed:
Dec. 29, 1989
James J Wisniewski, Sterling, VA (US);
Hubbell Incorporated, Orange, CT (US);
Abstract
A telephone system uses above voice-band ASK control and supervisory signals which are appended to digitally encoded voice by forcing the least significant bits to a selected level for transmission to the receiving end. At the receiving end, the ASK is regenerated by a circuit including special filter. To eliminate audible noise resulting from the filter action, the ASK signal is applied to a shaping circuit which shapes the leading and trailing ASK envelope into a gradually increasing and decreasing envelope. To detect the proper number of pulses in the signal, a threshold detector is used which follows the envelope, ignoring peaks of low amplitude after peaks of high amplitude.