Transmission system with improved tone detection
US5850437A · kind A · utility
2Cited by
8References
31Claims
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 signalling tone is transmitted by a transmitter to a receiver via a transmission channel. In the receiver, a tone detector detects the presence of a signalling tone. In order to improve a reliability of the tone detector, a number of correlating elements which determine a correlation value between an input signal and a reference signal are used. Absolute output signals of the correlating elements are added by an adder to derive a combined correlation signal to be used for detection.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.