QPSK and 16 QAM self-generating synchronous direct downconversion demodulator
US6717462B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 15, 2002 |
| Grant date | Apr 6, 2004 |
| Priority date | — |
| Expiry date | Jun 18, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D3/247
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A system for recovering and demodulating a carrier includes a carrier recovery loop and a data detector. The carrier recovery loop receives the carrier as an input and produces a recovered carrier at a frequency approximately equal to that of the carrier. The carrier recovery loop includes a downconverting mixer, a ×5 multiplier, a ×4 multiplier, and a phase locked loop. The downconverting mixer receives the carrier input, and the phase locked loop provides a VCO reference frequency through the ×5 multiplier to the downconverting mixer, which provides a frequency shifted signal. The frequency shifted signal is passed through the ×4 multiplier as input to the phase locked loop. The data detector receives the carrier and the recovered carrier as inputs and uses the recovered carrier to demodulate the carrier and detect I channel data and Q channel data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.