| 摘要 |
PURPOSE:To improve the anti-interference performance of a demodulator and to improve the secrecy of a modulation signal by using two spread code generators in the modulator and the demodulator so as to generate spread code series signals of the identical level but with a deviated timing, and ORing them exclusively. CONSTITUTION:Same number of spread code series generators 13, 15 are operated in both the modulator and the demodulator and the outputs are subject to exclusive OR processing, and the spread code series generators 13, 15 receive an instruction signal from a timing circuit 1 to generate the spread code series signals different in timing. But the deviation of the timing should not be an integer multiple of a sub-bit pulse width tau. The plural number of the spread code series signals generated in the timing as above are inputted to an exclusive OR circuit 17, the output of which can be applied to modulation by using the spread code series signals having a smaller sub-bit pulse width. |
