Spread spectrum signal generating device and method

There is provided spread spectrum signal generating device and a method in a transmitter of a mobile communications system using a plurality of logical channels. In the spread spectrum signal generating device, a multiplexer time multiplexes a pilot channel signal and a control channel signal which are output at a constant power levels, a first orthogonal encoder orthogonally spreads the output of the multiplexer with an orthogonal code, a second orthogonal encoder orthogonally spreads voice channel data of a variable bit rate with an orthogonal code, a third orthogonal encoder orthogonally spreads packet channel data of a variable bit rate with an orthogonal code, an IQ signal mapper adds the outputs of the first and third orthogonal encoders, outputs the added signal as a first channel signal, and outputs the output of the second orthogonal encoder as a second channel signal and a PN spreader spreads the first and second channel signals with PN codes and outputs a final spectrum spread signal. Therefore, a peak-to-average power ratio of the transmitter is maintained so as to be substantially uniform.