Use of 64-QAM circuitry for receiving and decoding 8-VSB signals
US6292518A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 1999 |
| Grant date | Sep 18, 2001 |
| Priority date | — |
| Expiry date | Oct 21, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L27/02
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An N-VSB (vestigial sideband) modulation signal is converted into an M-QAM (quadrature amplitude modulation) signal, where M=N.sup.2, by shifting the symbol rate frequency of a received N-VSB modulation signal to center the waveform spectrum about zero Hertz prior to complex demodulation so that data symbols will alternately appear on demodulated I and Q channels. A pilot tone of the received N-VSB modulation signal is removed to eliminate any bias in the both I and Q channels. Symbol timing between I and Q channels is offset, and quadrature amplitude demodulation of the I and Q channel signals generate alternating I and Q channel data symbols. Alternating inversion of the alternating I and Q channel data symbols recovers the N-VSB symbol data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.