PURPOSE: To independently correct an amplitude and a phase individually by calculating the amplitude and the phase of a complex number signal from input signals I, Q at a 1st arithmetic circuit and outputting the signals I, Q from the corrected amplitude and phase so as to compensate the distortion of an amplifier by a 2nd arithmetic circuit respectively.
CONSTITUTION: An arithmetic circuit 100 calculates an amplitude Ai and an angle (phase) θi of a complex number signal from input signals 1-I, 1-Q. An arithmetic circuit 101 calculates I, Q signals from the amplitude and angle of the corrected complex number signal for the distortion compensation of the amplifier. A ROM 110 is written with a distortion compensation data for the amplifier and outputs Ai(t) and θi(t) with respect to Ai(t). Part of an output signal to the amplifier to an input terminal 4 is subjected to envelope detection with respect to the characteristic change in the amplifier due to a temperature change or the like and the result is converted into an analog signal by an A/D converter 60, a change is detected by a correction quantity generating circuit 80 to rewrite the RAM 111. Thus, even when the characteristic of the amplifier is changed due to a temperature change or the like, only the amplitude characteristic is compensated.
TOYOSHIMA HAJIME
SUEMATSU KENJI
IKEDA YUKIO
TAKAGI SUNAO
URASAKI SHUJI
| JPS61214843A | 1986-09-24 |