AMPLIFIER CIRCUIT, TRANSMITTER, METHOD FOR AMPLIFICATION AND TRANSMISSION

摘要

PROBLEM TO BE SOLVED: To solve the problem that in a transmission circuit using a Delta Sigma modulator, its characteristics such as high efficiency, low distortion and low noise which can be realized when a certain output is assured, is deteriorated when the output is lowered. SOLUTION: An amplifier comprises the Delta Sigma modulator 803 for Delta Sigma modulation of signals, an amplifier 804 connected to an output side of the Delta Sigma modulator 803. The amplifier is an amplifier circuit in which an output voltage of the Delta Sigma modulator 803 is controlled in accordance with the output power from the amplifier 804. When the output power from the amplifier 804 lowers, the output voltage of the Delta Sigma modulator 803 is lowered. COPYRIGHT: (C)2004,JPO