| 摘要 |
A TV receiver for receiving and signal-processing analog and digital broadcasting signals includes a dual tuner and control unit for automatically controlling RF gain of the dual tuner. A controller applies a channel select control signal according to each broadcasting viewing mode to the dual tuner and applies a AGC select signal of each broadcasting mode to a switch. The dual tuner selects a channel of a corresponding broadcasting mode among the received broadcasting signals according to the applied channel select control signal, controls the gain of the RF signal of the selected channel according to an applied automatic gain control signal, and converts the gain-controlled RF signal into an IF signal. A signal distributor identifies and outputs the IF signal output from the dual tuner according to the selected broadcasting mode (analog or digital). An analog processor restores an analog composite video signal from an analog IF signal. A digital processor restores a baseband digital video signal from a digital IF signal. Each of the analog and digital processors generates a respective automatic gain control signal (AGCa and AGCd) according to the restored signal levels. The switch selects one of AGCa and AGCd to be supplied to the dual tuner. Accordingly, the TV receiver can be simply constructed to save on production costs, and provides for easy control of an analog/digital dual tuner using a channel select control signal and a AGC select signal according to each broadcasting mode.
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