IIR数字滤波器的设计及软件实现

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(a)s(t)的波形32s(t)10-100.0020.0040.0060.0080.010.0120.0140.0160.018t/s(b) s(t)的频谱0.021幅度0.5002004006008001000f/HZ12001400160018002000

（2）N=1800时：

(a)s(t)的波形32s(t)10-100.0050.01t/s(b) s(t)的频谱10.0150.02幅度0.5002004006008001000f/HZ12001400160018002000

（3）N=2000S时：

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(a)s(t)的波形32s(t)10-100.0050.010.0150.020.025t/s(b) s(t)的频谱1幅度0.5002004006008001000f/HZ12001400160018002000

3、修改信号产生函数mstg，给每路调幅信号加入载波成分，产生调幅（AM）信号，重复本实验，观察AM信号与抑制载波调幅信号的时域波形及其频谱的差别。

AM信号表示式：s?t???A?Acos?2?ft??cos?2?ft? A?Adm0cdm

取值：Ad?10 ，Am?5，结果见（附录Ⅰ）

六．实验结果（程序附录Ⅱ）

原信号输出：

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(a)s(t)的波形32s(t)10-100.0010.0020.0030.0040.0050.0060.007t/s(b) s(t)的频谱0.0080.0090.011幅度0.5002004006008001000f/HZ12001400160018002000

低通输出：

(a) s(t)损耗函数曲线0-20-40-60-80幅度（dB）00.10.20.30.40.50.6?/?(b) s(t)的波形0.70.80.9110.50-0.500.010.020.030.040.05t/s(c) s(t)的频谱0.060.07y(n)幅度10.5002004006008001000f/Hz12001400160018002000

带通输出：

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(a) s(t)损耗函数曲线0-20-40-60-80幅度（dB）00.10.20.30.40.50.6?/?(b) s(t)的波形0.70.80.9110.50-0.500.010.020.030.040.05t/s(c) s(t)的频谱0.060.07y(n)幅度10.5002004006008001000f/Hz12001400160018002000

高通输出：

(a) s(t)损耗函数曲线0-20-40-60-80幅度（dB）00.10.20.30.40.50.6?/?(b) s(t)的波形0.70.80.9110.50-0.500.010.020.030.040.05t/s(c) s(t)的频谱0.060.07y(n)幅度10.5002004006008001000f/Hz12001400160018002000

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