Patent ID: 7486131

Claim:
A quadrature demodulator which generates an I signal by multiplying a binary modulated reception signal and a local signal with each other, generates a Q signal by multiplying the reception signal and a local signal shifted in phase by 90 degrees, and generates binary data from the I signal and Q signal, the demodulator comprising: I signal sign detecting means for detecting a sign of the generated I signal; Q signal sign detecting means for detecting a sign of the generated Q signal; I signal multiplying means for multiplying the generated I signal by the sign of the I signal that appears at a non-modulated time; Q signal multiplying means for multiplying the generated Q signal by the sign of the Q signal that appears at a non-modulated time; signal adding means for adding an output of the I signal multiplying means, and an output of the Q signal multiplying means; and data generating means for generating binary data from a signal output from the signal adding means.