提出了一种用有效能量评估有效带宽截断误差的方法.采用梯形波作为信号模型，通过matlab 计算，分析了非正弦信号有效带宽0.35 /tr的能量截断误差和物理含义; 阐述了理想矩形信号常用1 /τ 带宽的不足，提出了其修正公式.结果表明，有效带宽0.35 /tr的能量截断误差小于3%; 带宽1 /τ 的能量截断误差高达10%，故修正为3 /τ.信道和示波器的带宽应大于信号的有效带宽.

A method of evaluating the truncation error of the effective bandwidth is proposed. Taking a trapezoidal wave as a signal mode and using MATLAB calculations，the energy truncation error and physical nature of the effective bandwidth formula 0.35 /tr for a non-sinusoidal wave are analyzed，and the disadvantages of the bandwidth formula 1 /τ for an ideal rectangular wave are explained. The analysis results show that the truncation error of the effective bandwidth formula 0.35 /tr is less than 3%，and the truncation error of the formula 1 /τ is less than 10%. Therefore，the effective bandwidth formula for the ideal rectangular wave is modified to be 3 /τ. The bandwidths of a signal channel and an oscilloscope should be chosen greater than the effective bandwidths of the measured signals.