RADIO COMMUNICATION DEVICE

摘要

A bit error ratio of the reception signal at the reception side is detected. According to this bit error ratio, an optimal modulation method and LO output power are determined and an LO output modification instruction is sent to an image suppression mixer of the transmission side. The image suppression mixer changes the phase X = alpha + gamma according to the LO output modification instruction when a power distributor (201) divides the LO into two parts with equal amplitude and a phase difference alpha, a power distributor (202) divides the IF signal into two parts with equal amplitude and a phase difference beta, and a power synthesizer (205) synthesizes the RF signal with equal amplitude and a phase difference gamma. By changing the X, the LO output power is controlled and the back off amount of the transmission amplifier is modified according to the optimal modulation method. Here, alpha - beta + gamma = 2npi (n is an integer) is set so as to obtain the maximum image suppression amount.