| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To improve an S/N in spread spectrum communication. <P>SOLUTION: In a transmitter, a spreading code having a chip width which is natural-number times of one cycle of a cyclic signal is generated, and the cyclic signal is multiplied with the spreading code for transmitting a resultant spreading signal. In a receiver, the reception signal is made synchronous with the spreading code, and the reception signal is multiplied with the spreading code. Since the chip width of the spreading code is natural-number times of one cycle of an original cyclic signal, if the chip rate of the spreading code is sufficiently high relative to change of the original cyclic signal, multiplying results of the reception signal and the spreading code have almost the same waveforms (35A<SB>1</SB>-35A<SB>m</SB>) in view of time interval corresponding to the chip width of the spreading code within the range of one code length of the spreading code. By extracting the multiplying results at the time interval and adding them, only a signal component among the multiplying results is emphasized with a noise component being relatively suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
