| 摘要 |
A dual HDTV/NTSC receiver for recovering one of a HDTV signal and a NTSC signal coexisting in a desired channel includes a tuning unit for converting a desired one of HDTV signals and NTSC signals into an intermediate frequency (IF) signal, a sync detector, coupled to receive the IF signal for detecting a sync signal of the NTSC signal, a timing recovery unit, coupled to receive the IF signal for self-recovering symbol timing of the applied HDTV signal, and providing a symbol timing lock signal corresponding to the IF signal and an analog-to-digital converted HDTV signal, a controller for judging whether a currently received television signal is either a NTSC signal or a HDTV signal based on the sync detection result of the sync detector and the symbol timing lock signal from the timing recovery unit, and for outputting a control signal according to the determination result, and a tuning controller for initially controlling the tuning unit so that one desired HDTV signal is received, and for subsequently controlling the tuning unit on the basis of the signal selected by the control signal among respective HDTV and NTSC signals output, respectively, from the tuning unit and the timing recovery unit. The receiver automatically determines whether a received signal is the NTSC signal or the HDTV signal.
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