Nonsynchronous independent side band AM stereo decoder
US4694501A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 10, 1984 |
| Grant date | Sep 15, 1987 |
| Priority date | — |
| Expiry date | Dec 10, 2004 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04H20/49
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An AM stereo receiver uses an AM detector (208) and an asynchronous PM detector (206) to decode AM stereo signals. The AM stereo broadcast signal has a carrier signal phase modulated with a modified phase shifted left channel minus right channel (L-R) audio signal, which is then amplitude modulated with a phase shifted left channel plus right channel (L+R) audio signal. The AM detector (208) within the receiver decodes the phase shifted L+R signal, while the PM detector 206 within the receiver decodes the modified phase shifted L-R signal. A phase shifter (214) restores the L+R and L-R signals to their proper phase relationship. A matrix circuit (228) regenerates the left and right channel signals from the L+R and L-R signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.