| 摘要 |
PROBLEM TO BE SOLVED: To perform normal quadrature demodulation on a plurality of reception signals in spite of using one sampling clock by using a numerical controlled oscillator for a variable local signal generator when demodulating a baseband signal from an IF signal obtained by performing frequency conversion on the reception signals simultaneously with A/D conversion in a case where a plurality of transmission signals of different frequencies are to be received. SOLUTION: A bottom frequency in a plurality of frequencies determined from an inputted RF signal and a frequency of the sampling clock is selected for a frequency of the IF signal generated by an A/D converter, that IF signal is multiplied by a local signal at the 1/4 frequency of the sampling clock in a pre-stage mixer, and the baseband signal is then demodulated in a post-stage mixer by a local signal generated by the variable local signal generator using the numerical controlled oscillator. COPYRIGHT: (C)2008,JPO&INPIT
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