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1. (WO2001037503) METHOD AND SYSTEM FOR ANALYTICALLY COMPUTING AND USING AN ANSPCM SIGNAL

Pub. No.:    WO/2001/037503    International Application No.:    PCT/US2000/031808
Publication Date: Sat May 26 01:59:59 CEST 2001 International Filing Date: Sat Nov 18 00:59:59 CET 2000
IPC: H04L 1/00
H04L 1/24
H04L 5/14
H04L 25/49
Applicants: 3COM CORPORATION
Inventors: MUELLER, A., Joseph
ROSENLOF, John
Title: METHOD AND SYSTEM FOR ANALYTICALLY COMPUTING AND USING AN ANSPCM SIGNAL
Abstract:
A method and system for analytically and dynamically generating a repeatable digital probing signal representing an answer tone. The probing signal may conveniently be used by a modem to determine whether characteristics of the communication path between the modem and another end are sufficiently similar to these of a previous communication path, such that a shortened training sequence can be employed between two ends. When the modem initiates communication, the modem applies a predefined algorithm to dynamically generate a sequence of samples representing an answer tone signal. Next, the modem encodes the generated sequence of samples into a sequence of codewords and sends it to a second modem via a transmission path. When the second modem receives each codeword of the sequence, the second modem dynamically generates a respective codeword and compares it to the received codeword. Using the received sequence of codewords and the dynamically generated sequence of codewords, the second modem may determine whether a shortened training sequence may be employed.