| 摘要 |
PURPOSE: An automatic gain controller adapted to a noisy multipath channel to stably capture and track signals, a digital television receiver including the automatic gain controller, and a digital television receiving method are provided to control IF/RF gains and stably capture a VSB(Vestigial SideBand) signal. CONSTITUTION: An automatic gain controller includes a signal estimator(510), a signal state detector(520), an AGC(Automatic Gain Control) traffic control and saturation detection unit(530), and an IF/RF gain controller(540). The signal estimator receives a VSB digital signal and a demodulation signal of the VSB digital signal, selects one of the signals, measures the power value of the selected signal, and outputs coefficient update information that is varied with a degree of saturation state of the demodulation signal when locking information is activated. The signal state detector outputs level information of the power value, noise detection information, normal state detection information and oscillation detection information. The AGC traffic control and saturation detection unit activated the locking information when the normal state detection information is activated, outputs a reset signal activated under a predetermined condition when both of an integral IF AGC signal and an integral RF AGC signal are saturated, and outputs IF hold information and RF hold information according to switching scheme having hysteresis. The IF/RF gain controller generates a final RF gain control signal and a final RF gain control signal. |
