Patent ID: 7209526

Claim:
An apparatus for detecting imbalances between an I-channel signal and a Q-channel signal in order to suppress a spurious signal in a direct conversion digital quadrature transmission system having a digital signal processor and a weaver type frequency mixer, the apparatus comprising: means for generating a first compensation signal and a second compensation signal based on a digital I-channel signal and a digital Q-channel signal generated from the digital signal processor; means for generating an I-channel baseband signal and a Q-channel baseband signal by converting a radio frequency transmitting signal outputted from the direct conversion digital quadrature transmission system into a low frequency signal by squaring the radio frequency transmitting signal and multiplexing the low frequency signal with two sine waves having difference phases; and means for detecting a phase imbalance and an amplitude imbalance between the digital I-channel signal and the digital Q-channel signal by using a correlation between the first compensation signal and the second compensation signal with the I-channel baseband signal and the Q-channel baseband signal.