| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a system capable of reducing the suppression of the reception sensitivity by decreasing high power of a disturbing wave mixed in the band of a desired wave and improving the ratio of a desired wave / disturbance wave after despreading. <P>SOLUTION: A wireless section 2 amplifies a received wave received by an antenna 1 and subjected to spectrum spreading, gives the amplified wave to an A/D conversion section 3, which applies A/D conversion to the received wave. The A/D-converted received wave passes through a diffusion demodulation section 4, wherein the received wave is subjected to spectrum despreading and demodulated, and the result passes through a band pass filter 5 having a sufficiently narrow pass band, wherein noise other than the desired wave is attenuated. Then, when a spread modulation section 6 applies spread processing to the output of the filter 5, the signal whose noise out-band components are attenuated by passing through the filter 5 is spread, the entire noise energy is reduced more than that before passing through the spread demodulation section 4, and when a spread demodulation section 7 demodulates again the signal, the desired wave remains as it is and only the noise level is reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
