Patent 06940966 - Method and apparatus for detection of a telephone CPE alerting signal > Summary

Patent No. US 06940966

Published on Sep 6, 2005

Application No. 10/079969

Filed on Feb 21, 2002

Priority Date -

Lee, Julian - Vancouver, CA (7)

A method and apparatus for detecting a signaling tone within a communications channel, such as a telephone line, is presented. The energy level of the communications channel signal is measured at the frequency of the signaling tone and at one or more frequencies that are integer divisors of the signaling tone (i.e. at one or more subharmonics). The subharmonic energies are evaluated in determining whether the signaling tone is present. The technique can be implemented using a plurality of resonators and a comparator.

Tran, Sinh