| 摘要 |
PURPOSE:To amplify power of a modulation wave at a high efficiency while a distortion factor of the modulation wave is always reduced in an excellent way by controlling variably a delay based on a frequency error between a linear modulation wave subjected to envelope control and a setting reference frequency component. CONSTITUTION:An envelope signal is delayed at a variable delay circuit 7 by a desired value and obtained as a power amplifier control signal via a D/A converter circuit 8 and received by an envelope control circuit 9 as an envelope control signal to control an envelope of the modulation wave from a quadrature modulation circuit 5 in a desired way with respect to the envelope signal. As a result, a less distortion modulation wave is obtained as an object to be power-amplified from the circuit 9 and outputted from the circuit 9 to the power amplifier. The modulated wave from the circuit 9 is detected frequency components at the frequency error detection circuit 12 via an A/D conversion circuit 15 then its frequency components is compared with reference frequency components stored in a memory 14 in advance. Thus, the frequency error signal is obtained and the delay of the circuit 7 is controlled based on the frequency error signal. |
