Spread spectrum transmitter, spread spectrum receiver and spread spectrum communication method and automatic gain control circuit for spread spectrum receiver
US6160838A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 9, 1997 |
| Grant date | Dec 12, 2000 |
| Priority date | — |
| Expiry date | Dec 9, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/709
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A spread spectrum transmitter and receiver are provided wherein data can be accurately decoded by removing the effect of mutual interference of the quadrature component and in-phase component even when there is carrier frequency error. In a method of spread spectrum communication using a QPSK modulation system, there are provided: a demodulating circuit that receives and demodulates a signal transmitted with a prescribed time difference Td applied between the IQ components; correlators that find the mutual correlation of the IQ components and spreading code; a sampling circuit that samples their output signals; a phase calculator that calculates the phase from the ratio of the IQ components of these output signals; a differential decoding circuit that performs differential decoding on this output signal; an automatic frequency control circuit that corrects the frequency error of this output signal; a decoding circuit; and a clock recovery circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.