Device for phase synchronizing a reproduced reference carrier signal with windows specified for preselected ones of amplitude and phase modulated signal points
US4057762A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 21, 1976 |
| Grant date | Nov 8, 1977 |
| Priority date | — |
| Expiry date | Dec 21, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3818
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A phase synchronizer for a reference carrier signal reproduced in a receiver for a combined amplitude and phase modulated signal comprises a window specifier for specifying windows for preselected ones of true signal points of which the demodulated signal is selectively representative. The phase synchronizer includes a demodulator for producing complex signals representative of coarse signal points so long as the reproduced carrier signal has a phase error which falls within the windows. Differences between the true points and the coarse points falling within the windows are calculated and summed up to produce a control signal for reducing the phase error substantially to zero.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.