Adaptive multiplex blend control for stereo decoder to maintain signal to noise ratio
US4216353A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 27, 1979 |
| Grant date | Aug 5, 1980 |
| Priority date | — |
| Expiry date | Mar 27, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/1676
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An integrated circuit stereo decoder includes a blend control input terminal. The DC control voltage on this input terminal determines channel separation. During multiplex FM reception of multi-path signals, the signal strength signal has AM and a DC components. By detecting and amplifying the AC component and adding it to the DC component of the signal strength signal, in phase opposition, the presence of multi-path can be made to reduce the resulting combined signal strength signals which, in turn, is connected to the blend control terminal. Accordingly, the presence of multi-path reduces separation to maintain signal to noise ratio and reduce distortion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.