Carrier regeneration circuit
US4114710A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 20, 1976 |
| Grant date | Sep 19, 1978 |
| Priority date | — |
| Expiry date | Aug 20, 1996 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/3836
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A carrier regeneration circuit regenerates the carrier from the QAM (Quadrature Amplitude Modulated) received signal, as produced and transmitted by a quadrature partial response modulation system wherein quadrature-related carriers (i.e., having a phase difference of 90.degree.) of the same frequency are amplitude modulated with two parallel signals which have been subject to partial response conversion. The carrier regeneration circuit comprises a probability decision circuit which decides the probability of generation of particular demodulated data code combinations, and a carrier regeneration control circuit which maintains the phase ambiguity of the regenerated carrier within an integer multiple of 90.degree.. The control circuit responds to the output of the probability decision circuit for selectively shifting the phase of the regenerated carrier by 45.degree..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.