Method of controlling a threshold decoder for a signal having several levels and being affected by echoes, and television receiver provided with such a decoder
US5274674A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 7, 1991 |
| Grant date | Dec 28, 1993 |
| Priority date | — |
| Expiry date | Jun 7, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/4923
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
For controlling the threshold of a threshold decoder with a logic signal having several levels (for example a duobinary signal) which may be affected by echoes, and in which the threshold value of the decoder is programmable, the threshold of the decoder is adapted in dependence upon the measurement of the binary error rate, when there are echoes. Starting from a given threshold value (A), the corresponding binary error rate (P) is measured and, based on this binary error rate, a value which is referred to as criterion (K1) is computed (by adding a first fixed quantity to the value of the measured error rate and by multiplying the total by a second fixed quantity), subsequently the threshold value of the decoder is incremented step by step (B, C, D) and the criterion is recomputed at each step and used if it has become smaller, and when the binary error rate exceeds the criterion for the first time (D), the threshold value is stored and the process is continued by decrementing (C, B, A, E, F, G, H), and when the binary error rate (H) exceeds the criterion (K2) for the second time, half the sum of the two extreme values found (D,H) is chosen as the threshold control value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.