Butterworth digital low-pass filter, the passband range 0 ~ 40 hz, passband maximum attenuation ldB,
(ap=1 db), more than 150 hz for stopband, minimum decay is 60 db (as=60 db),
Design requirements:
1. According to the requirement to design Butterworth digital filter
(1) the design meet the requirements of indicators of analog filter
(2) the partial fraction expansion, pole mapping to get digital filter
2. Verify the design of the filter amplitude-frequency characteristic
(1) analog filter frequency response analysis
(2) digital filter frequency response analysis
(3) draw a comparison datum
(4) compared to
Set the sampling frequency for stopband cutoff frequency of 4 times, eight times, repeat the above process, compared the changes of amplitude frequency characteristic curve,
3. The principle part to describe using impulse response is not political reform method of digital IIR filter design steps, the matlab software programming, matlab source code is given and the simulation results;
4. The MATLAB source code for the necessary comments, to analyze the simulation results; 5. Writing curriculum design report according to the requirement,