FM/FMX stereophonic receiver
US4809328A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1988 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Feb 16, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/1692
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An FM/FMX stereophonic receiver is capable of receiving an FM or an FMX stereophonic broadcast signal. The FM stereophonic broadcast signal includes a stereo sum signal and stereo difference signal, whereas the FMX stereophonic broadcast signal further includes a compressed stereo difference signal and an FMX ID signal indicating the FMX stereophonic broadcast signal. The FM/FMX stereophonic receiver has a stereo demodulator for receiving said broadcast signal and for producing left and right stereo signals, a detector for detecting the field strength of the receiving signal, and a noise reducer, which may be a circuit for changing the mode from stereophonic mode to monaural mode or a high cut circuit for attenuating the signals of high frequency region, for reducing noise signals contained in the left and right stereo signals. The FM/FMX stereophonic receiver further has a detector for detecting the FMX ID signal and a disabling circuit for disabling the noise reducer when the FMX ID signal is detected by the detector. Instead of the disabling circuit, a timing control circuit may be provided for changing the timing at which the noise reducer starts to activate in response to the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.