Apparatus and method of oqpsk in ds-cdma system

PURPOSE: An OQPSK(Off-Set Quadrature Phase Shift Keying) device and method of a DS-CDMA(Direct Sequence-Code Division Mobile Access) mobile communication system is provided to use a pseudo orthogonal code. CONSTITUTION: A zero crossing detector(219) detects a zero crossing of an I-arm signal and a Q-arm signal, and outputs a detected signal. A delayer(221) performs a 90 degree phase delay for the Q-arm signal, and outputs the signal. The Q-arm signal is applied to a multiplexer(222) as one input signal. The 90 degree phase delayed signal is applied to the multiplexer(222) as an another input signal. The multiplexer(222) outputs one of the applied two signals by the detected signal, and performs a switching for the outputted signal.