Method and apparatus for measuring signal to noise ratio in a TDMA communications system
US4408322A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1980 |
| Grant date | Oct 4, 1983 |
| Priority date | — |
| Expiry date | Nov 7, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B17/20
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for measuring signal to noise ratio in a time division multiple access (TDMA) communications system which does not require that normal communications be interrupted. The signal to noise ratio measurement is performed on the unmodulated carrier which typically occurs in the preamble of each information burst in the TDMA format. In order to perform the measurements on the carrier of the same burst in each frame, the carrier and noise powers are sampled at a predetermined time with respect to specified information which occurs at the same time in each frame, normally the frame reference burst. After being converted to the receiver intermediate frequency, the unmodulated carrier is fed to both a narrow band pass filter having a pass band at the intermediate frequency and a narrow band stop filter having a stop band at the intermediate frequency. The ratio of the band pass filter output to the band stop filter output is the signal to noise ratio within a very small error.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.