TIADC系统误差自适应估计及补偿方法

时间交替并行采样模数转换器结构(TIADC)是提高系统采样率的一种有效方法。TIADC结构的实现过程中不可避免的会引入时间失配误差、增益误差和偏置误差从而导致系统的信噪比降低。针对上述问题,提出一种基于可变步长最小均方算法(VSS-LMS)的TIADC失配误差自适应估计方法。该方法可以同时完成对时间失配误差和偏置误差的估计,并根据估计得到的失配误差参数对失配误差进行校正。仿真结果表明,该自适应估计方法每通道仅需要不超过128个采样点即可以完成对失配误差的估计。最后在实际的时间交替并行采样系统中验证了该算法的有效性,该算法可以使得校准后的并行采样系统的信噪比提高20 dB。仿真与实验结果表明,所提出的算法可以有效提高TIADC系统的性能。

Adaptive estimation and compensation method for mismatch in TIADC system

Time interleaved analog to digital convert (TIADC) is used to improve the sampling rate of ADC system effectively. However, the timing mismatch, gain mismatch and offset mismatch are unavoidable in the TIADC system, which degrades the signal to noise ratio (SNR) of the TIADC. In this paper, an adaptive estimation method based on VSS LSM algorithm is proposed, which can estimate the timing mismatch and offset mismatch simultaneously. According to the estimated values, the timing and offset mismatches are corrected. The simulation results show that the proposed algorithm requires less than 128 samples to estimate the timing and offset mismatches of each sub ADC. The effectiveness of the proposed algorithm is verified in an actual TIADC system. The SNR of TIADC system is improved by 20 dB. The simulation and experiment results show that the proposed algorithm improves the performance of TIADC system effectively.