| 摘要 |
PROBLEM TO BE SOLVED: To prevent a misjudgment by an analog broadcast signal or a noise signal etc, and to determine the presence or absence of digital broadcasting waves with proper accuracy, and moreover, to do it efficiently at a high speed. SOLUTION: The digital broadcasting receiving device comprises a tuner, an IQ demodulating unit, an AGC (automatic gain control) control circuit, a GI (guard interval) eliminating circuit, a mode determining circuit, an AFC (automatic frequency control) circuit, a FFT circuit, an OFDM (orthogonal frequency division multiplex) frame decoding unit, a TMCC (Transmission and Multiplexing Configuration Control) regenerating circuit, a broadcast wave determining circuit, and a CPU. The AGC control circuit generates and outputs an AGC level signal. The mode determining circuit generates and outputs a mode determination result signal. The AFC circuit generates and outputs a frequency synchronization detection signal. The TMCC regenerating circuit generates and outputs a TMCC frame synchronization detection signal. The broadcast wave determining circuit determines whether a digital broadcasting wave has been received using the AGC level signal, the mode determination result signal, the frequency synchronization detection signal, and the TMCC frame synchronization detection signal; and outputs it to the CPU as a broadcast wave detection signal. COPYRIGHT: (C)2004,JPO&NCIPI
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