APPARATUS AND METHOD FOR PREVENTION DEGRADATION OF TRANSMISSION SIGNAL IN MOBILE COMMUNICATION SYSTEMS

摘要

An apparatus and a method for preventing degradation of a transmission signal in a mobile system are provided to prevent characteristics degradation of a transmission signal by actively changing a DC offset voltage for adjusting signal characteristics of an IQ modulator by feeding back the transmission signal. A transmission signal which has been modulated into an RF signal by the nth IQ modulator is split(201). The split transmission signal is demodulated by an IQ demodulator so as to be converted into a baseband signal(203). An LO feedthrough value of the split transmission signal is checked(205). The DC offset voltage value of the n+1 th transmission signal is determined according to the checked LO feedthrough value(207). IQ modulation is performed on the n+1 th transmission signal by using the determined DC offset voltage(209).