| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a delay synchronization loop circuit, a digital re-distortion type transmitter, and a radio base station for extracting accurately a non-linear distortion superimposed in a transmission output from the digital pre-distortion type radio transmitter. <P>SOLUTION: The delay synchronization loop circuit includes a variable delay element 105 to which first IQ signals Ir, Qr are entered, a subtractor 103 to which output signals If, Qf of the variable delay element and signals Id, Qd based on second input IQ signals Ii, Qi are entered, a delay comparator 106 to which the output signals If, Qf of the variable delay element are entered, and a smoothing filter 107 for entering and smoothing an output signal of the delay comparator and generating an output to the variable delay element. In the delay synchronization loop circuit, delay control for restricting distortion in the output IQ signal passing through an analog circuit unit is carried out by the variable delay element. One of first and second IQ signals is generated from output IQ signals Io, Qo, which are subjected to A/D conversion and passed through the analog circuit unit and further subjected to A/D conversion. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
