To accurately detect a reception level and increase demodulation S/N without being disturbed by a received spread signal level by putting the output of a synchronizing signal generation part and the output of a reference voltage generation part together into the reference voltage of a comparison part.
A correlative demodulation part 1 matches a receive signal against a set spread code and inputs a burst correlation output to a delay detection part 2 when they match each other. The output of a detection part 2 is supplied to a positive-polarity comparison part 4 and a negative-polarity comparison part 5 through an amplification part 3. A level detection part 7 processes the output of the detection part 2 by full-wave rectification through square detection, performs level detection, and sends the output to a synchronizing signal generation part 8. The generation part 8 sends a synchronizing signal as a reference signal to the comparison part 4 and also sends it as the reference signal to a comparison part 5 through a polarity inversion part 9. The comparison parts 4 and 5 decides data of the positive polarity and negative polarity. A demodulation part 6 regenerates a data clock from the outputs of the generation part 8 and inversion part 9 and demodulates receive data from the outputs of the comparison parts 4 and 5.
MOGI MINORU
TAMARU KENJI
TAMIZU KAZUHIDE
MORI KAZUYUKI
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