| 摘要 |
PURPOSE:To suppress the deterioration in the frequency utilizing efficiency by providing a distortion compensation section detecting the output distortion of an amplifier and applying inverse characteristic to a transmission modulation signal. CONSTITUTION:A reception signal from an antenna 6 is demodulated by a demodulator 10 via a switching section 11, a high frequency filter 5, a switch 13, a multiplier 7a, a low pass filter 8, an A/D converter 9 and a switch 16. A modulation signal from a modulator 1 at transmission is led to the antenna 6 via an inverse characteristic addition circuit 15, a multiplier 2a, an amplifier 3, a distributer 2 and a switching section 11. A part of the output from the distributer 12 enters a distortion detection circuit 14 via a switch 13, a multiplier 7a, the filter 8 and a converter 9, the output distortion of the amplifier 3 is detected and the inverse characteristic of the detected distortion is applied to the output of the modulator 1 by the circuit 15. Thus, a nonlinear power amplifier is employed for the transmission section while suppressing an out-band radiation due to the nonlinear distortion to suppress the reduction in the frequency utilization efficiency. |
