| 摘要 |
PROBLEM TO BE SOLVED: To control the level of a digital television signal to constant. SOLUTION: This AGC circuit calculates the absolute value of a vector consisting of I and Q base band signals whose phase is corrected and compares the absolute value with a reference level. A PWM generator 12 generates a PWM pulse. A 2nd LPF 13 eliminates a high frequency component of the PWM pulse, which is D/A-converted into a gain control signal 'cont' to control the gain of an amplifier 1. Thus, the level of a digital television signal before the detection is controlled to be a constant value.
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