| 摘要 |
PURPOSE: An adaptive predistortion linear apparatus is provided to easily embody the inverse characteristic of a linear circuit to the nonlinear characteristic of main amplifier by detecting envelops of an input and an output of a power amplifier, comparing the input with the output of the power amplifier, and changing an amplitude and a phase according to the difference of the input and the output of the power amplifier. CONSTITUTION: A high-speed gain/phase adjuster(20) adjusts a level and a phase of a signal divided to the first path. A low-speed gain/phase adjuster(30) adjusts a level and a phase of a signal outputted from the high-speed gain/phase adjuster(20). A main amplifier(80) amplifies a level of an inputted signal as a uniform level and compensates a level and a phase of the signal according to adjusted quantities of the high-speed gain/phase adjuster(20) and the low-speed gain/phase adjuster(30). A high-speed gain/phase controller(50) controls the adjusting quantity of the high-speed gain/phase adjuster(20) according to an envelop detected from a signal divided to the second path. A low-speed gain/phase controller(60) detects the envelop from a reference signal(R) delayed during a uniform time, detects another envelop from a feedback signal(M), compares two detecting values, and controls the adjusting quantity of the low-speed gain/phase adjuster(30) according to a difference value as the result of the comparison.
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