低通滤波器的阶跃响应及其对动态校准的影响

动态测试系统在利用阶跃信号进行动态校准时,系统中的低通滤波器环节所产生的衰减振荡可能会误导测试人员,特别是对于带传压管道的动态压力测试系统。仿真与测试结果表明,各种模拟低通滤波器和IIR数字低通滤波器的阶跃响应都会出现一定的衰减振荡。针对带低通滤波器的系统以及其他系统的阶跃激励校准,通过对简单FFT频响分析方法、矩形单脉冲法、冲激响应法三种方法的比较,发现矩形单脉冲法能更正确地对阶跃校准数据进行频响分析。

Step Response of Lowpass Filter and Its Influence on Dynamic Calibration

When a dynamic measurement system is calibrated with step signal,the damping oscillation produced by the lowpass filter may mislead researchers,especially for dynamic pressure measurement systems with pressure tubes.Emulation and test results indicate that damping oscillations appear in the step responses of analog lowpass filters and IIR digital lowpass filters.Aiming to analyze the frequency characteristic based on the step response of these systems,three methods including simple FFT method,single rectangle pulse method and impulse response method are compared,and the single rectangular pulse method is found to analyze the data more accurately.