| 摘要 |
A gain-controlled amplifier capable of dealing with the system for performing the receiving operation continuously, and capable of correcting a change of a DC offset owing to an operation condition such as temperature; a receiver circuit using the gain-controlled amplifier; and a radio communication device installing the receiver circuit. In a gain-controlled amplifier composed of three GCA stages ( 11 )-( 13 ) connected by cascade connection, the center value of an output DC of each GCA stage ( 11 )-( 13 ) is kept to be constant by a common feedback circuit ( 16 )-( 18 ) provided correspondingly to each of the GCA stages ( 11 )-( 13 ), and a DC feedback quantity is made to be changed according to a gain control voltage VG by means of a DC feedback circuit ( 19 ) provided between an output side of a last stage of the GCA stages and an input side of a first stage of the GCA stages.
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