Transmission system with improved tone detection
US5850438A · kind A · utility
6Cited by
8References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 16, 1996 |
| Grant date | Dec 15, 1998 |
| Priority date | — |
| Expiry date | Apr 16, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q1/44
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a transmission system, a tone is transmitted by a transmitter to a receiver via a transmission channel. In the receiver, a tone detector is used to detect the presence of a signalling tone. In order to improve a reliability of the tone detector when the arrival of the signalling tone is unknown, a number of correlators having mutually displaced measuring periods are used. More than two correlators are used in order to reduce the measuring period, also resulting in an improved reliability of the tone detection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.