Receiving device and signal demodulating method

Abstract

A receiving device includes: a signal receiving section for receiving signals modulated by spread codes and transmitted; a frequency converting section for converting frequencies of received signals received by the signal receiving section into intermediate frequencies; an A / D converting section for converting the received signals whose frequencies are converted into intermediate frequencies into digital signals to produce sample values of the received signals; a base band reproducing section for removing intermediate frequencies from the sample values produced by the A / D converting section to reproduce base band signals; a local code producing section for producing local codes identical to the spread codes used by transmission side of the signals; a plurality of multipliers each of which multiplies the base band signals by the local codes and outputs a correlation value between the base band signals reproduced from the sample values and the local codes; an adder for adding the plural correlation values outputted from the plural multipliers; and an integrator for integrating the outputs from the adder for one cycle of the spread code and outputting the integral value of the correlation values. Each of the plural multipliers receives sets of the base band signal reproduced from the sample value and the local code, which sets received by the multipliers are produced at different chip positions for each of the plural multipliers.

Description

technical field [0001] The present invention relates to a receiving device and a signal demodulation method for receiving a signal modulated by a spread symbol. Background technique [0002] In order to receive and demodulate a signal modulated by a spectrum spread method such as CDMA (Code Devision Multipel Access: Code Division Multiple Access), it is necessary to match the phase of the spread symbol of the received signal with that generated inside the receiver. The phases of the diffuse symbols (local codes) are consistent. In addition, in the case where the relative speed of the receiving side and the transmitting side is large and the apparent (see かけ) frequency change of the received signal based on the Doppler effect cannot be ignored, the frequency of the local code also needs to consider the Doppler effect. [0003] In order to judge the phase and frequency consistency between the received signal and the local code, for example, a local code that staggers the phas...

AI Technical Summary

Problems solved by technology

[0009] However, in the configuration of Patent Document 1, there is a problem that the number of integrators (correlators: correlators) which occupy a large area relative to the entire circuit cannot be reduced.

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