Patent ID: 8063703

Claim:
An output circuit of a radio-frequency (RF) transmitter comprising: a first variable gain amplifier configured to have a first variable gain within a first gain variable range based on a first variable width and to amplify an input signal; a second variable gain amplifier configured to amplify a signal provided from an output of the first variable gain amplifier and to have a second variable gain within a second gain variable range larger than the first gain variable range based on a second variable width larger than the first variable width; and a gain control unit configured to fluctuate the second variable gain in steps of the second variable width in response to fluctuations of the first variable gain, the fluctuations of the first variable gain being attained within the first gain variable range, wherein the first gain variable range corresponds to the second variable width, wherein the first gain variable range is larger than the second gain variable range, and wherein the gain control unit performs control so that a minimum gain within the first gain variable range is increased by a value of the first variable width each time that the second variable gain increases.