| 摘要 |
PURPOSE: An adaptive pre-compensating method using μ-law function is provided to compensate a non-linear distortion generated from the saturation characteristics by using a μ-law function. CONSTITUTION: A pre-compensator(10) compensates a non-linear and linear distortion of the inputted signal by using a reverse function. A delay device(20) delays the inputted signal by δsample in order to ensure the realization possibility of the pre-compensator(10). A winner system(30) performs a modeling of the signal outputted from the pre-compensator(10) by using a non-linear system connected in series a linear dynamic subsystem and non-memory non-linear subsystem. A first subtracter(40) generates a whole error signal by subtracting the output signal of the winner system(30) from the output signal of the delay unit(20). A system estimator(50) estimates the non-linear distortion of the signal outputted from the pre-compensator(10). A second subtracter(60) calculates a mean error by subtracting the output signal of the winner system(30) from the output signal of the system estimator(50). A filter coefficient updating unit(70) updates the filter coefficient of the system estimator(50) by the mean error obtaining from the second subtracter(60). A reverse function calculation unit(80) calculates the reverse function of μ-law function by the non-linear distortion signal obtained from the system estimator(50) and the whole error signal obtained from the first subtracter(40) and then updates the filter coefficient of the pre-compensator(10).
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