Patent ID: 7248112
Filing Date: 2007-07-24
Classification: H03F

Abstract:
1. A hybrid distortion compensation method of digital control using both pre-distortion processing of a digital signal and distortion canceling processing of a feed forward scheme, said method comprising: a first step of performing pre-distortion processing on an input digital signal by a pre-distortion circuit, converting the pre-distortion processed digital signal into an analog signal, amplifying the converted analog signal by a power amplifier, converting the amplified signal into a digital signal, and adaptively controlling a pre-distortion characteristic of said pre-distortion circuit based on the converted digital signal; a second step of converting each of the output signal of said power amplifier input to a main path of a circuit that performs said distortion canceling processing of the feed forward scheme and a reference signal input to a feed forward loop into a digital signal, measuring characteristics of each converted signal by using digital signal processing, and adjusting at least one of gain, phase, and delay of said reference signal based on the measuring results such that the characteristics of said converted signals are the same; a third step of converting a signal of said feed forward loop in said circuit that performs the distortion canceling processing of the feed forward scheme into a digital signal, detecting a correlation between the digital signal and said reference signal to measure a leakage amount of the reference signal contained in said signal of the feed forward loop, and determining the adjusting result of the second step; and a fourth step of converting the output signal of said circuit that performs the distortion canceling processing of the feed forward scheme into a digital signal, and monitoring whether a predetermined characteristic of the converted digital signal is within a permissible range by using digital signal processing.