| 摘要 |
PROBLEM TO BE SOLVED: To prevent the linearity deterioration of an output signal of a nonlinear distortion compensating transmitter equipped with a fault discriminating function and a linearizer by discriminating the fault or gain fluctuation of the analog circuit section of the transmitter in an early stage. SOLUTION: In the nonlinear distortion compensating transmitter, the linearizer composed of a multiplier 8-1, a distortion compensation table 8-2, a distortion compensation factor update section 8-3, and a subtracter 8-4, is provided. As to data for detecting defective operation in the transmitter, a distortion compensation factor S1 or an error signal S2 is measured. The distortion compensation factor S1 is read from the distortion compensation table 8-2 of the linearizer. The error signal S2 is a difference between an input signal (base-band signal) to a distortion compensation target outputted from the subtractor 8-4 and a feedback signal outputted at the final stage via the non- linear circuit, and inputted to the distortion compensation factor update section 8-3. Then, by monitoring the changed value of the observation point by means of a fault discriminating section 1-1, whether or not the transmitter is out of order is discriminated.
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