Distortion compensation amplification apparatus of feed forward type and adaptive pre-distortion type

Abstract

A feed forward type distortion compensation amplification apparatus, which includes a distortion detection loop and a distortion compensation loop, cancels a first distortion element generated from the distortion detection loop by a second distortion element generated from the distortion compensation loop to generate an output signal, and controls bias levels of the main amplifier and the error amplifier based on a level of the output signal. An adaptive pre-distortion type distortion compensation amplification apparatus includes a detection unit for detecting an input power level, a control unit for storing the input power level and a bias level corresponding thereto and generating the bias level in response to the input power level, and a bias control unit for applying a bias to an amplifier unit in response to the bias level.

What is claimed is:  
     
         1 . A feed forward type distortion compensation amplification apparatus, comprising: 
 a distortion detection loop having a first phase shifter, a first amplitude adjuster and a main amplifier;    a distortion compensation loop having a second phase shifter, a second amplitude adjuster and an error amplifier;    means for canceling a first distortion element generated from the distortion detection loop by a second distortion element generated from the distortion compensation loop and generating an output signal; and    a bias controller for controlling bias levels of the main amplifier and the error amplifier based on a level of the output signal.    
     
     
         2 . The apparatus of  claim 1 , wherein the bias controller includes a first bias control unit for controlling a bias of the main amplifier and a second bias control unit for controlling a bias of the error amplifier.  
     
     
         3 . The apparatus of  claim 1 , wherein the output signal is classified into one of a plurality of output levels and the bias levels of the main amplifier and the error amplifier are determined based on the classified output level.  
     
     
         4 . The apparatus of  claim 2 , wherein the output signal is classified into one of a plurality of output levels and the bias levels of the main amplifier and the error amplifier are determined based on the classified output level.  
     
     
         5 . The apparatus of claims  2 , wherein each of the main and the error amplifier includes one or more amplifier units and each of the first and the second bias control unit includes one or more bias control circuits.  
     
     
         6 . The apparatus of  claim 5 , wherein the number of amplifier units included in the main amplifier is identical to that of bias control circuits included in the first bias control unit and the number of amplifier units included in the error amplifier equals to that of bias control circuits included in the second bias control unit.  
     
     
         7 . An adaptive pre-distortion type distortion compensation amplification apparatus, comprising: 
 a detection unit for detecting an input power level;    a control unit for storing the input power level and a bias level corresponding thereto and generating the bias level in response to the input power level; and    a bias control unit for applying a bias to an amplifier unit in response to the bias level.    
     
     
         8 . The apparatus of  claim 7 , wherein the control unit stores therein a plurality of input power levels and their corresponding bias levels.  
     
     
         9 . A distortion compensation amplification apparatus, comprising: 
 a detection unit for detecting a level of an input signal;    an amplification unit for amplifying the input signal; and    means for stepwise controlling a bias of the amplification unit based on the level of the input signal detected by the detection unit.    
     
     
         10 . A distortion compensation amplification apparatus, comprising: 
 an amplification unit for amplifying an input signal;    a detection unit for detecting a level of an output signal; and    means for controlling a bias of the amplification unit based on the level of the output signal detected by the detection unit.