We derive theoretical results on soliton interactions and timing jitter in soliton transmission systems by use of super-Gaussian filters of high order. It is shown that the soliton interactions and timing jitter can be effectively suppressed by filters of various orders. We get that the minimum value of two-soliton separation is maintained almost constant during propagation for different filter orders. The optimal filter for sliding frequency in suppressing soliton interaction is determined. We also show that the higher the filter order is, the better the improvement of the timing jitter is.