Patent ID: 8891697

Claim:
A reception signal processing device which down converts a reception signal of a high frequency to a base-band by using a direct conversion system, the reception signal processing device comprising: a mixer section which mixes the reception signal with a local oscillation signal of a predetermined frequency to perform a frequency conversion; an amplifying section including a plurality of variable gain amplifiers formed in multi-stages, wherein the plurality of variable gain amplifiers include a first variable gain amplifier and a second variable gain amplifier provided in a post-stage of the first variable gain amplifier; a converter which converts an analog signal amplified by the amplifying section to a digital signal; isolation switches respectively provided in post-stages of the first variable gain amplifier and the second variable gain amplifier; a bypass switch section which sets to open and close a path in which an output of the first variable gain amplifier bypasses the second variable gain amplifier and is inputted to the converter; a switch controller which controls the isolation switches and the bypass switch section so that the outputs of the first variable gain amplifier can be inputted to the converter without passing through the second variable gain amplifier; and a DC offset controller which sets a correction value for a DC offset in accordance with a gain set in the first variable gain amplifier as an object to be corrected when the reception signal is not inputted to the first variable gain amplifier as the object to be corrected and when an output of the first variable gain amplifier of the object to be corrected is inputted to the converter without passing through the second variable gain amplifier.