Patent ID: 7756195

Claim:
A demodulator for estimating a demodulation value of a received signal by correlating a PN code sequence of PN code having a periodic relationship for each code with a sample of the received signal, the demodulator comprising: an IF processor unit separating the received signal to select only an imaginary part of the received signal, and digitalizing the selected imaginary part of the received signal; a differentiator unit delaying the received signal outputted from the IF processor unit by preset delay time, and multiplying the delayed received signal by a current received signal to output a plurality of differentiated received signals; a conjugate unit sequentially storing samples of the imaginary parts of the differentiated received signals, and calculating correlation values by correcting the stored samples with PN coded sequences; a timing estimator unit receiving the differentiated received signals and controlling an operating timing of the conjugate unit; and a demodulation value estimator unit storing the correlation values outputted from the conjugate unit and estimating the symbol of the PN code sequence corresponding to a maximum correlation value as the demodulation value of the received signal.