US 6,650,689 B1 · Correlator and delay lock loop circuit

Abstract

The present invention reduces the scale of circuitry and shortens the code phase detection time needed to achieve initial synchronization. In a correlator for calculating correlation between a received spreading code contained in a received spread-spectrum signal and a reference spreading code, a combined code generator is included. The combined code generator outputs a combined spreading code by weighting and combining a plurality of phase-shifted reference spreading codes A1-AM. Further, an arithmetic circuit calculates correlation between the received spreading code and the plurality of phase-shifted reference spreading codes simultaneously. A phase detection circuit detects the phase difference between the received spreading code and a reference spreading code, namely the phase of the received spreading code from the results of the arithmetic operation.

Claims6

Dependent claims

A correlator for determining a phase difference between a received spreading code included in a spread spectrum signal and a reference code, comprising:

a reference spreading code generator for generating the reference spreading code;
a generator for generating a plurality of weighted and phase shifted occurrences of the reference spreading code;
a combined code generator for generating a combined spreading code by combining said plurality of weighted and phase shifted occurrences of the reference spreading code;
arithmetic circuit for calculating a correlation between the received spreading code and the combined spreading code;
and
a phase detector for detecting a phase difference between the received spreading code and the reference code based upon the level of the correlation output from the arithmetic circuit.

3 more elements

A correlator for determining a phase difference between a received spreading code included in a spread-spectrum signal and a reference spread code comprising:

a reference spreading code generator for generating the reference spread code;
a first combined code generator for generating a first combined code by applying first weighting to a plurality of phase-shifting occurrences of the reference spreading code on the basis of values obtained by sampling one period of a sine-wave signal in units in which a phase shift is performed and then combining the plurality of phase-shifted occurrences of the references spreading code after being weighted;
a first arithmetic circuit for calculating a first correlation between the received spread code and the first combined code;
a second combined code generator for generating a second combined code by applying second weighting to a plurality of phase-shifted occurrences of the spreading codes on the basis of values obtained by sampling one period of a cosine-wave signal in units in which said phase shift is performed and then combining the plurality of phase-shifted occurrences of the references spreading code after being weighted;
a second arithmetic circuit for calculating a second correlation between the received spread code and the second combined code;
and
a third arithmetic circuit for determining a phase difference between the received spreading code and the reference code by dividing the first correlation by the second correlation.

4 more elements

Dependencies are inferred from the claim text.

Correlator and delay lock loop circuit

Life of this patent

Correlator and delay lock loop circuit

Life of this patent

Abstract

Claims6