Multiplex demodulation circuit
US4399324A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 3, 1980 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Sep 3, 2000 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D1/2209
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A multiplex demodulation circuit in which no band elimination filter is required for eliminating beating between the mixed signals and odd harmonics of the 38 KHz switching signal derived from the 19 KHz pilot signal. The FM detection signal is logarithmicly converted as is the 38 KHz subcarrier signal. The two logarithmically converted signals are added and then inversely logarithmically converted. The inversely logarithmically converted signal is added to the FM detection signal to produce the left channel signal while the inversely logarithmically converted signal is phase inverted then added to the FM detection signal to provide the right channel signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.