Patent attributes
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.
