Patent ID: 7430233

Claim:
A spread-spectrum demodulator comprising: N (N is an integer not less than 2) sample/hold circuits each of which samples/holds a received spread signal; a sample/hold control circuit which receives a first clock having the same frequency as that of a clock used to spread a baseband signal, and performs control to make said N sample/hold circuits sequentially perform sample/hold operation in synchronism with the first clock; a first spreading code generating circuit which generates N first spreading codes in synchronism with a second clock; a second spreading code generating circuit which generates N second spreading codes obtained by rearranging the first spreading codes in reverse order in synchronism with the second clock; N multipliers which multiply signals output from said sample/hold circuits and spreading codes output from said first spreading code generating circuit or said second spreading code generating circuit for each corresponding signal; an adder which adds outputs from said N multipliers; a peak detector which detects a peak of an output from said adder and demodulates a data signal on the basis of the detected peak; and a spreading code control circuit which alternately switches inputting of the first spreading codes from said first spreading code generating circuit to said multipliers and inputting of the second spreading codes from said second spreading code generating circuit to said multipliers every time the peak is detected by said peak detector.