| 摘要 |
A spread spectrum communication system is to control the signal amplitude variation so as to alleviate the requirement of the linearity on the amplifier etc., thus allowing for use of a compact, low cost and energy saving transmitter. The transmission signal is separated into the I-phase component and the Q-phase component. In a complex spreading portion (301), spreading is performed by using multipliers (304 and 305) and adders (302 and 303) together with a sequence pattern of 1 and -1 appearing alternately. The outputs from the complex spreading portion (301) are modulated in multipliers (306 and 307) using pseudo-random sequences PN<(k))<x) allotted for individual users. The baseband signal which underwent waveform shaping by roll-off filters (308 and 309) is modulated through a carrier modulator (316), then sent to a power amplifier (315), where it is amplified and transmitted via antenna (317). <IMAGE> |
