Stereo composite processor for stereo radio receiver
US4198543A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 1979 |
| Grant date | Apr 15, 1980 |
| Priority date | — |
| Expiry date | Jan 19, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03G5/18
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A radio receiver is effective to receive a radio frequency signal and derive therefrom a standard stereo composite signal comprising a sum of channels signal having components within a first band of frequencies in the audio range and a difference of channels signal having components within a second band of frequencies above the first band of frequencies. The radio receiver is provided with a low pass filter having a high frequency roll-off characteristic within the first frequency band and a substantially flat attenuated amplitude characteristic across the second frequency band. Linear mixer apparatus mixes filtered and unfiltered stereo composite signals in controlled relative proportion responsive to a control signal to produce a modified stereo composite signal for application to stereo decoder apparatus in order to simultaneously roll-off the high frequencies in each derived channel and to attenuate the difference of channels signal in degree controlled by the control signal. Control signal generating apparatus provides said control signal in response to a parameter indicative of noise in the stereo composite signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.