Method and apparatus for detection of a telephone CPE alerting signal
US6940966B2 · kind B2 · utility
61Cited by
5References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 21, 2002 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | Nov 30, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M15/06
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.