Method and apparatus for adjusting the postamble false detection probability threshold for a burst transmission
US5577056A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1995 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Feb 24, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L7/042
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for adjusting the postamble false detection probability threshold for transmission systems that carry telephony network signals using binary-phase shift-keying (BPSK) burst transmission format. The postamble marks the end of a burst transmission. The method and apparatus herein classifies the type of signal present on the telephony network and utilizes a control loop to change the threshold, if necessary, to minimize the probability of false detection of the postamble during demodulation. Transmission of speech signals, which are bursty in nature, suffer little degradation from false detection of a postamble. However, transmission of fax, voice-band data modems and other types of longer-duration signals are severely affected by a false detection of the postamble unique word. Therefore, fax, modem and other longer duration signals have their threshold adjusted to minimize the false detection probability after the signal has been classified as such.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.