RECEIVER WITH DIRECT CURRENT OFFSET CORRECTION FUNCTION AND METHOD FOR CORRECTING DIRECT CURRENT OFFSET IN RECEIVER

摘要

PROBLEM TO BE SOLVED: To prevent the sensitivity deterioration of a receiver by accurately correcting a baseband direct current offset voltage. SOLUTION: A radio signal from an antenna 1 is converted into an intermediate frequency signal by a high frequency block 2, transmitted to an orthogonal mixer 8 through an impedance compensation block 7, converted into a baseband signal and transmitted to a baseband signal processing block 10. Direct current offset voltage detection blocks 16a and 16b detect a direct current offset voltage existing in the block 10 on the basis of an output of an orthogonal modulator 11 at a time when the block 2 is off, and direct current offset voltage cancel control blocks 17a and 17b correct the direct current offset voltage based on the detected offset voltage. The block 7 compensates the fluctuation of output impedance at on/off of the block 2.