MATLAB与Python程序互转：实例解析（二）

echo on
T=1;
Fs=2/T;
Ts=1/Fs;
c_opt=[-2.2 4.9 -3 4.9 -2.2];
t=-5*T:T/2:5*T;
x=1./(1+((2/T)*t).^2);		        % sampled pulse
equalized_x=filter(c_opt,1,[x 0 0]);	% since there will be a delay of two samples at the output
% to take care of the delay
equalized_x=equalized_x(3:length(equalized_x));
% Now, let us downsample the equalizer output
for i=1:2:length(equalized_x),
  downsampled_equalizer_output((i+1)/2)=equalized_x(i);
  echo off;
end;
figure(1)
stem(equalized_x)
figure(2)
stem(downsampled_equalizer_output)

import numpy as np
from scipy import signal
import matplotlib.pyplot as plt

T=1
Fs=2/T
Ts=1./Fs
c_opt=np.array([-2.2,4.9,-3,4.9,-2.2])

t=np.linspace(-5*T, 5*T, 21)
x=1./(1+(2/T*t)**2)
x_ = np.hstack((x,np.zeros((2,))))
print(c_opt,np.array([1]),x_)

equalized_x=signal.lfilter(c_opt,np.array([1]),x_);
equalized_x=equalized_x[2:equalized_x.size]
print(equalized_x)

downsampled_equalizer_output = np.zeros((int(equalized_x.size/2+1),))
#% Now, let us downsample the equalizer output
for i in range(0,equalized_x.size,2):
    downsampled_equalizer_output[int((i+1)/2)]=equalized_x[i];
print(downsampled_equalizer_output)

plt.figure(1)
plt.stem(equalized_x)
plt.figure(2)
plt.stem(downsampled_equalizer_output)
plt.show()