| 摘要 |
PROBLEM TO BE SOLVED: To provide a group delay characteristic correcting circuit, with which the group delay distortion of an analog band-pass filter can be corrected by digital signal processing, stability in frequency characteristics is high, adjustment is not required and the circuit scale is not expanded. SOLUTION: The frequency of an RF signal received by an antenna 5 is converted by a mixer 6, the band thereof is limited by a band-pass filter 7 and affected by the group delay distortion. Further, the frequency is converted by a mixer 8 again, the band is limited by a band-pass filter 9 and affected by the group delay distortion. Next, quadrature demodulation is performed by a quadrature demodulation part 10, respective common-phase and orthogonal components are A/D converted by an A/D converting part 11, an arithmetic means 12 applies filter operating processing to a digital filter having characteristics inverse to the group delay characteristics of analog band-pass filters 7 and 9 stored in a storage means 16, and signals are demodulated by a signal demodulating part 13. Thus, a code decision error in signal demodulation can be reduced.
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