Patent ID: 7450925

Claim:
A receiver for a wireless communication system, the receiver comprising: a low noise amplifier which low-noise-amplifies a data signal of a transmitter; down-converting mixers which convert the data signal to a base band; filters which remove noise from the data signal; amplifiers which amplify the data signal; an oscillator which generates differential signals; first switches which apply the differential signals generated by the oscillator or the data signal of the transmitter to the down-converting mixers; a frequency conversion part which mixes and applies to the down-converting mixers quadrature signals obtained through processing a signal of an arbitrary clock signal generator and quadrature signals obtained through processing the differential signals generated by the oscillator, the frequency conversion part comprising a first poly-phase filter which changes a phase difference between I/Q signals according to a control voltage; a phase difference detection part which detects a phase difference between the I/Q signals, generates the control voltage which applied to the first poly-phase filter according to the phase difference, and corrects the phase difference; second switches which provide to analog-to-digital converters the data signal processed through the down-converting mixers, filters, and amplifiers, and provides the phase difference detection part with I/Q signals having predetermined frequencies; and a control unit which controls switching of the first and second switches to apply the differential signals generated by the oscillator to the down-converting mixers when the I/Q signals are compensated for, and applies the I/Q signals having the predetermined frequencies to the phase difference detection part.