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:
Jun. 23, 1998
Filed:
Aug. 25, 1995
Bertram F Kupersmith, Avon, CT (US);
Julian H Shull, Jr, Southington, CT (US);
Otis Elevator Company, Farmington, CT (US);
Abstract
A telephone transmit circuit is connected through a resistor to a junction at which a telephone line interface circuit is connected, a transhybrid cancellation circuit is connected to the transmit circuit and includes a high frequency shunt matching network having capacitive and inductive components and a low frequency matching circuit which comprises a lead lag network having capacitive components, the output of the transhybrid circuit being connected to a summing junction at the input of a telephone receiver. The other input of the summing network is connected between the resistor and the interface circuit, whereby a portion of the transmit signal is fed back out of phase to the receive amplifier so as to cancel out undesirable side tones, across a predetermined frequency range.