设计一个IIR数字低通滤波器， 逼近一组模拟滤波器的指标参数（通带截止频率Wp=2*pi*2000rad/s,阻带边界频率Ws=2*pi*3000rad/s,通带波纹 Rp=3db, 阻带衰减Rs=15db, 采样频率f=10000Hz）； 分别用脉冲响应不变法和双线性变换法实现设计，列出传递函数并描绘模拟和数字滤波器的幅频和相频响应曲线。用上述设计滤波器完成几组给定信号的滤波，证明滤波器的有效性和滤波范围限制.-Design a IIR digital low-pass filter, app

桨叶嵌入式液弹吸振器，是一种新型的桨叶减摆器，该函数功能是求桨叶在一阶激励频率下的幅频响应，-Liquid bomb embedded blade vibration absorber, is a new blade damper, the function function is seeking an order in the blade under the excitation frequency amplitude-frequency response,

求频响函数的实频、虚频、幅频、相频及Nyqiust图-Seeking FRF real frequency, imaginary frequency, amplitude and frequency, phase frequency and Nyqiust Figure