Patent ID: 6041082
Filing Date: 2000-03-21
Classification: H03C,H04N

Abstract:
A digital amplitude modulation amplifier, comprising:an A/D converter for converting an analog modulation signal into a digital signal of a predetermined quantization bit number;a plural number of power amplifiers equal to the quantization bit number of the digital signal for C class operating with amplification degrees weighted for the individual bits;selectively inputting means for selectively inputting a carrier to said plural number of power amplifiers in accordance with values of the individual bits of the digital signal;coupling means for power composing, for all bits, output signals of those of said plural number of power amplifiers which are allocated to lower bits and output signals of those of said plural number of power amplifiers which are allocated to the other upper bits while controlling the phases of both of the output signals based on an external input phase control signal, further power composing, for all of the bits, the power composed signals while controlling the phases of the power composed signals based on the output signals of those of said power amplifiers which are allocated to the upper bits and the external input phase control signal and outputting an amplitude modulated wave from the last stage; andphase controlling means for receiving the digital signal as an input signal and generating and supplying the external input phase control signal to said coupling means.