Digital duplex communication system
CA 1194166 A · Owner: N.V. Philips Gloeilampenfabrieken · Inventors: Virdee, Nirmal S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
17, ABSTRACT:, "Digital duplex communication system". A digital duplex communication system includes an echo canceller of the look-up table type. The echo canceller comprises a random access memory (RAM) (41) a digital to analogue converter (DAC) (45) a subtractor, (5), adaption means (47) and an address generator (40). The echo canceller stores echo replicas for combinations of data bits transmitted by the transmitter (1) and subtracts these echo replicas from a received signal on line (9) before application to the receiver (2). The capacity required for the RAM (41) is reduced by storing only one echo replica for each of two complementary sets of data. To achieve this the address …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted September 24, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 24, 2002.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
Timeline From CIPO dates
Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.