Stereo pilot signal eliminating circuit for AM stereophonic receiver
US4409436A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1981 |
| Grant date | Oct 11, 1983 |
| Priority date | — |
| Expiry date | Jun 17, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04H20/49
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An AM stereophonic receiver including a stereophonic pilot signal eliminating circuit which substantially completely eliminates a pilot signal in an input stage of a matrix detector. A received AM stereophonic signal, of the type in which the carrier signal is phase-modulated with a sub-signal and amplitude modulated by a main signal, is coupled to a main signal detector and a sub-signal detector. The output of the sub-signal detector is coupled through a band amplifier which produces as an output a signal corresponding to the pilot signal contained in the stereophonic signal. The outputs of the sub-signal detector and main signal detector are coupled to inputs of adder/subtractor circuit in a matrix detector while the output of the band amplifier is also coupled thereto in a phase so as to cancel the pilot signal contained in the output of the sub-signal detector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.