| 摘要 |
PURPOSE:To always improve a transmission spectrum characteristic with high accuracy by making a band of a transmission signal sufficiently narrow so as to apply initial setting and then passing through a normal signal at application of power or when a sample timing of a demodulator output is largely deviated. CONSTITUTION:A switching circuit 115 selects signals 111-I, 111-Q, then a delay till a signal returns to an input terminal 105 from an output terminal 104 is negligibly small in comparison with a time of a signal band. A signal conversion circuit 120 receiving the signals 111-I, 111-Q outputs complex signals 121-I, 121-Q, which represent addition of distortion to compensate the nonlinearity characteristic of an amplifier. The input signals 111-I, 111-Q are inputted to a subtraction circuit 160 through a variable delay circuit 161 together with outputs 151-I, 151-Q of AD converters. When an output of the subtractor circuit is not 0, a correction quantity generating circuit 170 multiplies (p) with the output of the subtractor circuit 160, an adder circuit 180 adds the output of the circuit 120 and the output of the correction quantity generating circuit, resulting signals 171-I, 171-Q are outputted to rewrite the content of the signal conversion circuit 120. |
