MATLAB (9)

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Frequency Response

Natural frequency

  • wn = sqrt(k/m)(rad/s) - 회전 주파수
  • fn = wn/(2*pi)(Hz) - 주파수
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>> m=10;
>> b=0.1;
>> k=1000;
>> wn=sqrt(k/m)

wn =

    10

Definition of dB

dB = -20log(Output/Input)

Bode plot

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num=[1];
den=[10 0.1 1000];
sys=tf(num,den);
bode(sys)

bode-plot-1

  • Hz
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num=[1];
den=[10 0.1 1000];
sys=tf(num,den);
bode(sys)
figure
h=bodeplot(sys);
setoptions(h,'FreqUnits','Hz');

k

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num=[1];
den=[10 0.1 1000];
den=[10 0.1 4000];

bode-plot-2

  • b is same in frequency domain