Plotting the bode plot of a high pass filter using matlab

Question

Cagin Kaya 2024-5-13

0
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https://ww2.mathworks.cn/matlabcentral/answers/2118381-plotting-the-bode-plot-of-a-high-pass-filter-using-matlab

回答： Star Strider 2024-5-13

I am trying to theoretically find the frequency response of the circuit given below:

Firstly i found the impedance value of the RC Ladder by applying the equation below, then i defined this as "Z" in my MatLab Code.

Afterwards i wrote a matlab code to plot the filter's frequency response. Matlab Code is given below, the required nominal values shown in the schematic are defined in the code.

    f = logspace(0, 5, 1000);
    w=2*pi.*f;
    s=1i.*w;
    
    Ro=11960e3;
    R1=2.17e3;
    R2=118.44e3;
    R3=496.82e3;
    R4=1220e3;
    R5=2530e3;
    
    C1=536.29e-12;
    C2=217.23e-12;
    C3=201.41e-12;
    C4=263.35e-12;
    C5=556.27e-12;
    
    Rload=200e3;
    
    Z=((1/Ro)+(R1+(1./(s*C1)))+(R2+(1./(s*C2)))+(R3+(1./(s*C3)))+(R4+(1./(s*C4)))+(R5+(1./(s*C5)))).^-1;
    
    H=abs(Rload./(Z+Rload));
    semilogx(f, 20*log10(H))

The LTSpice plot (expected one) is like this:

My Matlab Plot is like this:

My mathematical approach seems correct to me let me know if i have anything missing on that part. I am unsure about the code, please let me know if there is something missing in code or my mathematical approach.