时间交替ADC系统的一种动态误差补偿方法

目前有许多方法被用于补偿或减少时间交替ADC系统各个通道失配带来的误差,但这类方法仅考虑了静态效果,没有提供一种测量时间交替ADC系统误差的有效方法,对SFDR提高非常有限,并且难以满足实时性的要求.本文采用由状态空间索引的误差表对时间交替ADC系统的输出进行校准.该方法将某一通道作为参考通道,对其它通道的误差进行测量并生成由时间交替ADC系统输出状态索引的误差表,利用该误差表对各个通道的输出进行动态校准.最后将该方法用于400 MSPS/12 bit高速数字化仪的校准,在输入幅度为1 V的1 MHz正弦信号时,高速数字化仪的杂散失真可降低20 dB.

Dynamic error compensation for time interleaved ADC system

Great deals of techniques are applied to compensate or reduce distortions caused by the mismatches between ADC channels recently, but many techniques only consider static effects and do not provide a satisfactory way to measure time-interleaved ADC channel error. So the improvement of SFDR is limited to certain level, and the techniques couldn't be used in high speed real time process. This paper adopts state space indexed error table to correct the output of time-interleaved ADC system. This approach chooses one channel as the reference channel and uses this channel to measure the errors of other channels to construct an error table, which can be applied to compensate the dynamic errors of other channels. This approach was used to compensate a 400 MSPS/12 bit high speed digitizer and the result shows that this method can lower the estimated distortion caused by mismatches by 20 dB for a 1volt 1 MHz sinusoid input signal.