Patent attributes
A signal input into an input terminal 1 is input into mixers 2, 4, and down-converted with local signals having a phase difference of 90 degrees, respectively, whereby an I-signal and a Q-signal are obtained. An output signal from the mixer 4 is delayed 90 degrees in phase by a phase shifter 6. An adder 7 outputs a sum signal of the I-signal and the Q-signal, and a subtracter 8 outputs a subtracted signal between the I-signal and the Q-signal. The sum signal and the subtracted signal are input into band pass filters 9, 10, in which signals in undesired frequency band are cut, then converted into digital signals by AD converters 11, 12 and input into a signal processor 13. In the signal processor 13, a correlation signal of the sum signal and the subtracted signal is formed, and an image signal included in the sum signal is removed using the correlation signal and the subtracted signal.
