Apparatus and method of adaptive frequency offset estimations for a receiver
US7164731B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 31, 2003 |
| Grant date | Jan 16, 2007 |
| Priority date | — |
| Expiry date | Jul 12, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2027/0065
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
An apparatus for estimating frequency offset of a demodulator is disclosed. An input symbol is regarded as a rotating phasor obtained by consecutive sampling symbols, while the phasor encompasses an argument containing phase rotated by frequency offset and phase difference by modulation polarity. An adaptive judgment circuit encompassing a decision feedback way is employed to de-polarize the phasor, i.e. to move out the argument of modulation. The adaptive judgment circuit includes a decision circuit and a multiplier. The decision circuit of the adaptive judgment circuit receives the phasor fed from the phase-increment extraction circuit to find a de-noise phasor by using the product of the phasor and a de-noise symbol, wherein the de-noise symbol is determined according to an inner product of the phasor and a last summation stored in a summation circuit. In the multiplier, the de-polarized phasor is obtained by multiplying the phasor by the de-noise symbol before feeding into the next stage, summation circuit. A summation circuit is used for estimating de-polarize phasor by a summation of the de-polarized phasors, while the summation is fed back to the decision circuit for derivin…
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