采集系统通道传输特性校正

Correction to Transform Function of Data Acquisition Channel

采集系统中 ADC前端的抗混迭滤波器等模拟器件通常会对通道传输特性带来较大的幅相误差 ,对这些误差可以采用将采样序列通过数字校正滤波器的方法校正。本文首先介绍了校正通道幅相误差的几种办法 ,指出幅相误差必须同时校正以得到最佳性能 ;然后给出了求解逼近给定幅相频率响应的 FIR实系数滤波器的线性规划方法 ;最后 ,作者将这一算法应用在 70 0 Msps通道的双通道数据采集系统中 ,取得了很好的校正效果。

The anti-alias lowpass filters in data acquisition systems induce significant errors to trasfer characteristic of acquisiton channels, and these errors can be digitally corrected by using digital correction filters. This paper introduces approaches to reduce the distortion of trasfer channels firstly. Then a linear programming method is proposed to construct the FIR filter correcting the amplitude and phase errors simultaneously. Finally, this method is used to a 700 Msps/channel 2-channel high-speed data acquisition system, and the results prove that the method is feasible and efficient.