CDMA TRANSMISSION SYSTEM AND RADIO DEVICE USING SAME TRANSMISSION SYSTEM

摘要

PROBLEM TO BE SOLVED: To exclude intense variation of a spread code sequence waveform at a chip section end, to prevent the frequency bandwidth from increasing, and to improve the communication quality by excluding intense variation in spread code value which is continuous in a transition section when the spread code value is different between adjacent chip sections. SOLUTION: A CDMA transmitter is constituted by inserting spread code sequence waveform continuing circuits(CODE-CS) 150 to 15n between spread code generating circuits(CG) 130 to 13n and spreading circuits(SS) 120 to 12n. Those CODE-CSs 150 to 15n are provided and then only when the spread code value is different between adjacent chip sections, the spread code value can gently be varied in the transition section. In the CODE-CSs 150 to 15n, spread code sequences from the corresponding CGs 130 to 13n are inputted to adders and outputs at output terminals are inputted to and held in latch registers with leading edges of clock signals applied to clock terminals.