Acquisition synchronization and the phase modified between different types of data acquisition card

To narrow the scope of the phase difference between different hardware channels which were assigned to the different types of data acquisition board, the better software solution should be offered. In this paper, the unsteady and over-high phenomenon of phase difference were analyzed firstly. The different hardware channels adopted uniform clock and trigger at the same time. By this mean, the phase difference was minhnized and steadied. In order to further reduce the phase difference, the Second Order Butterworth Low Pass Filter (SOBLPF) with optimal phase signature was designed by using Matlab. An acquisition system with successive approximation A/D converters and delta-sigma A/D converters data acquisition boards was set up. The results of the tests indicated that this method can satisfy the requirements of phase difference at different types of hardware channels.