Carrier recovery scheme for a SSB-SC signal
US3984778A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 13, 1974 |
| Grant date | Oct 5, 1976 |
| Priority date | — |
| Expiry date | Nov 13, 1994 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/066
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A system is provided for extracting the proper carrier phase from a single sideband suppressed carrier signal. A received signal is equalized and then product demodulated by estimated in-phase and quadrature carriers produced by a voltage controlled oscillator (VCO). The outputs of the in-phase and quadrature product demodulators are low-pass filtered producing corresponding in-phase and quadrature baseband signals. An estimator compares the in-phase baseband signal with reference levels, samples the output of the comparing circuit at the band rate and generates a sequence of estimated data signals. The error signal, which forms the input to the VCO, is produced by multiplying the recovered quadrature baseband signal with the estimated data signals and is proportional to the product of the square of the low pass filtered baseband signal and the sine of the difference between the phases of the received carrier and estimated carrier.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.