| 摘要 |
PURPOSE: A variable order predistorter and a method for controlling thereof are provided to control nonlinear orders and coefficients so that the input/output characteristics of a nonlinear power amplifier and a power amplifier having a deteriorated characteristic can have linearity. CONSTITUTION: A variable order predistorter is provided with a low pass filter(21), a predistorter(22), a power amplifier(23), an order adjuster(24), and a coefficient adapter(25). The low pass filter(21) filters the signal transferred from the external to remove noise. The predistorter(22), composed of a square detector(221), a nonlinear part(222) and a multiplier(223), linearizes the signal filtered from the low pass filter(21). The power amplifier(23) amplifies the power of the signal transferred from the predistorter(22) and the power of the signal transferred from the order adjuster(24). The order adjuster(24) receives the signal outputted from the power amplifier(23) and adjusts an order. The coefficient adapter(25) adaptively updates the coefficient of the predistorter(22) using the signal inputted to the predistorter(22) and the signal outputted from the power amplifier(23).
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