| 摘要 |
PROBLEM TO BE SOLVED: To provide an AGC circuit restraining a signal of a large amplitude from being output. SOLUTION: The AGC circuit comprises: a variable gain amplifier (2); gain control means (3 and 4) for performing feedback control for the gain of the variable gain amplifier (2) so that an amplitude of an output signal of the variable gain amplifier (2) becomes an ideal one; input means (101, 102, and 1) for delivering an input signal from outside to the input of variable gain amplifier (2); and detection means (110 and 21) for detecting that a signal to be delivered to the input of the variable gain amplifier (2) is switched from a first signal to a second signal. In response to detection by the detection means (110 and 21), the gain control means (3 and 4) perform control for lowering the gain of variable gain amplifier (2) for a predetermined period, in place of the feedback control. The input means (101, 102, and 1) switches a signal delivered to the input of the variable gain amplifier (2) from the first signal to the second signal, after the predetermined period has passed. COPYRIGHT: (C)2009,JPO&INPIT
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