37 lines
988 B
Python
37 lines
988 B
Python
#!/usr/bin/env python
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import math
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import matplotlib.pyplot as plt
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def rk3(h,tn,yn,ys,param=[]):
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k1 = ys(tn,yn,*param)
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k2 = ys(tn+h/2,yn+h*k1/2,*param)
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k3 = ys(tn+h,yn - h*k1 + 2*h*k2, *param)
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return tn+h, yn + h*(k1/3 + k2/3 + k3/3)
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def main():
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U = lambda tn,f : math.sin(2*math.pi*tn*f)
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R = 5e3
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C = 1e-6
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us = lambda tn, un, f: (U(tn,f) - un)/(R*C)
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fc = 1.0/(2*math.pi*R*C)
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frequencies = [ 2**(i) * fc for i in range(-5,8)]
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ucmax_list = []
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ucmin_list = []
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for f in frequencies:
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print("Simulation f = %.3f Hz" % f)
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ucmax = 0
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ucmin = 0
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tn = 0
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un = 0
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for i in range(int(1000*f)):
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tn, un = rk3(1/(1000*f), tn, un, us, [f])
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ucmax = max(un,ucmax)
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ucmin = min(un,ucmin)
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ucmax_list.append(ucmax)
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ucmin_list.append(ucmin)
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plt.plot(frequencies, ucmax_list, 'r', frequencies, ucmin_list, 'b').show()
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if __name__ == '__main__':
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main()
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