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:
Feb. 25, 1997
Filed:
May. 22, 1995
Shrirang Jangi, Germantown, MD (US);
Hughes Electronics, Los Angeles, CA (US);
Abstract
An echo canceller for use in fixed-wireless telephony networks using low-rate packetized speech coding and DSI is disclosed. An adaptive filter is used to cancel an echo signal of a far-end signal introduced at the near-end by operating to provide a replica signal to cancel the echo signal. The replica signal is updated in the absence of a near-end talker signal presence of near talker signal is detected using an estimated echo-residual loss. The echo replica signal updating process is frozen upon the detection of double-talk. Residual echoes are suppressed without the use of non-linear processing. A residual suppression flag detection and a voice activated switching device are used to detect the absence of near-end signals. The switching device is opened if the signal to be transmitted is not a near-end signal or is noise.