| 摘要 |
PURPOSE: To provide a method and system for controlling a base-band gain by which the generation of a transient voltage can be suppressed in the gain setting of variable gain amplifiers of a base-band circuit. CONSTITUTION: A gain conversion circuit 113 places a limit to a gain change that can be changed at once. In the case that gain input data are changed by a large amount and a gain change in excess of the limit is required, the gain conversion circuit 113 controls variable gain amplifiers 102, 103, 104 at gain changes each of which is less than the limit value, so as to attain a required gain change. Furthermore, a gain distribution circuit 112 distributes gain control data to the variable gain amplifiers 102, 103, 104, in a way of sequentially increasing the gain from the variable gain amplifier closer to the input in the case of increasing the gain and in a way of sequentially decreasing the gain from the variable gain amplifier remotest from the input in the case of decreasing the gain, on the basis of gain output data of the gain conversion circuit 113.
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