| 摘要 |
PROBLEM TO BE SOLVED: To provide the digital demodulator that is able to process digital orthogonal detection, whose signal processing system includes no analog signal processing system that gives much effect on accuracy of demodulation without using complicated circuits, such as an orthogonal local oscillation signal generator and a multiplier. SOLUTION: In the digital demodulator, in which an A/D converter 9 converts an analog orthogonal amplitude modulation signal into a digital signal and digital orthogonal detectors 10i, 10q provide an output of a digital demodulation signal, a relation fS=4fIF/(2n+1) is established, where fIF is a carrier frequency of the analog orthogonal amplitude modulation signal, fS is a sampling frequency of the A/D converter 9, and n is a positive integer, so that a relation fC=fS/4 exists where fC is a frequency of the orthogonal local oscillation signal used for orthogonal detection by the digital orthogonal detectors 10i, 10q. |
