To provide a transmitter circuit provided self-optimizing the frequency, the function which is particularly used in the base station transmitter of a radio telecommunication system about a power amplifier for telecommunication use.

This transmitter circuit representatively operates over a specified transmission frequency range, consists of an oscillator (302) for generating a 1st signal in a 1st frequency, an up-converter (306) for converting the 1st signal having the 1st frequency into a 2nd signal having a 2nd frequency different from the 1st frequency and an amplifier (110) for amplifying the 2nd signal, the up-converter generates a control signal to the amplifier on the basis of frequency information used to specify the 2nd frequency, and the amplifier automatically optimizes an operation about 2nd signal amplification by using the control signal.