时间交替ADC系统通道时钟延迟的多频正弦拟合算法

Multi-tone sine wave fit algorithm of channel time delay in time-interleaved ADC system

时间交替ADC系统(TIADC)各个通道之间存在的时钟延迟失配会导致系统输出信号失真。减小系统输出失真的许多校准方法都是以准确估计各个通道时钟延迟为前提的。利用多频正弦拟合算法对输出数据进行拟合,并结合TIADC系统输出频谱表达式,获得各个通道时钟延迟。该方法不需要专门的测试信号和额外电路,对TIADC系统通道数量及采样率亦无限制。仿真及实验表明,该算法可有效获得TIADC系统的时钟延迟。

Time delay mismatches between each channel cause distortion in the sampled signal in time-interleaved ADC system.In order to calibrate the distortion effectively,it is important to calculate the channel time delays firstly.In this paper,time delay of each channel is obtained by combining multi-tone sine wave fit of TIADC outputs with output spectrum expression.Without using additional circuits and test signals,this method also has no limit on the channel number and sampling rate of TIADC.Simulation and experiment demonstrate that the algorithm can effectively calculate the time delay in TIADC.