| 摘要 |
PURPOSE: A device for demodulating a digital VSB(Vestigial Side Band) is provided to lower an IF as doubling a clock frequency of an A/D converter, and to perform a VSB demodulation process in a digital area without an interference, thereby exactly maintaining a phase difference of a carrier and improving demodulation performance. CONSTITUTION: An analog processor(200) multiplies the first IF signal by a predetermined frequency, and converts the first IF signal into the second IF signal lower than the first IF signal. A digital processor(220) converts an output of the analog processor(200) into a digital signal, and demodulates the digital signal. The digital processor(220) comprises as follows. An A/D converter(207) doubles an output of a buffer amplifier(206). An LPF(212) decimates demodulated I and Q channel digital signals to sample only one of the signals per symbol, and removes a high band. A timing recoverer(214) recovers a timing used as an A/D clock. An FS synchronous recoverer(215) compensates for signal deterioration. A carrier recoverer(216) recovers a carrier by using the demodulated I and Q channel digital signals.
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