Stereophonic receiving circuit providing improved switching characteristics between stereophonic and monaural modes
US4691357A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 11, 1985 |
| Grant date | Sep 1, 1987 |
| Priority date | — |
| Expiry date | Jun 11, 2005 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/1676
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A stereophonic receiving circuit in which automatic switchover from the monaural receiving mode to the stereophonic receiving mode as the input signal strength increases is made more smoothly and effectively by boosting the gradient of a S-meter control voltage above a certain level of the received signal. The conventional S-meter voltage is applied to one input of a differential amplifier, the other input of which receives a reference voltage. The output of the differential amplifier is applied to one input of an analog OR gate, the other input of which receives the S-meter voltage directly. The output of the analog OR circuit, which is the greater of the two inputs to the circuit, is applied to the control inputs of an electronic volume control circuit, a high-cut controller, and a stereophonic demultiplexer circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.