| 摘要 |
<P>PROBLEM TO BE SOLVED: To enable a digital processing section to perform frequency error detection and frequency correction processing when a receiver side receives a digital modulated signal and applies demodulation processing thereto. <P>SOLUTION: In a communication system using a digital modulation scheme in which a transition for each modulation cycle does not pass through a zero point, a receiver is equipped with an analog processing section for converting a received signal into an IF signal and a digital signal processing section 30 for applying frequency correction processing to the IF signal. The digital signal processing section 30 converts a digital signal (IF signal) converted by an A/D converter 19 into an in-phase signal (I) and a quadrature signal (Q) by using a quadrature demodulation processing part 31, detects a frequency error of the IF signal by using a frequency error detection part 34 and inputs it to a complex frequency conversion processing part 32. The complex frequency conversion processing part 32 applies frequency correction based on the frequency error detected by the frequency error detection part 34 to the in-phase signal (I) and the quadrature signal (Q) from the quadrature demodulation processing part 31 and at the same time applies complex frequency conversion to the in-phase signal (I) and the quadrature signal (Q) and outputs the signals to a demodulation processing part 33. <P>COPYRIGHT: (C)2007,JPO&INPIT |
