# Analyze of 3. Order Passive RLC Low Pass Filter

YILDIZ TECHNICAL UNIVERSITY
Department of Mechatronics Engineering

Lecture :

MKT 2822 Electronics and Communication Circuits

ANALYZE of 3. ORDER PASSIVE RLC LOW PASS FILTER with MATLAB

Divided Two Circuit

First Order Low Pass Filter                                          Second Order Low Pass Filter

Transfer Function of First Order Low Pass Filter

R=49.9 ohm  C=8.2 pF Cutoff Frequency of First Order Low Pass Filter Matlab Code of Bode Diagram

num=[2443912214.6732];

den=[1 2443912214.6732];

G=tf(num, den);

bode(G);

grid on;

title('First Order LPF Bode Diagram');

Bode Diagram of First Order Low Pas Filter with Matlab Figure

Transfer Funtion of Second Order Low Pass Filter

R=150 ohm  C=27pF  L=56nH Cutoff Frequency of Second Order Low Pass Filter Matlab Code of Bode Diagram

num=[6.6137566137566*1e17];

den=[1 246913580.24691 6.6137566137566*1e17];

G=tf(num, den);

bode(G);

grid on;

title('Second Order LPF Bode Diagram');

Bode Diagram of Second Order Low Pas Filter with Matlab Figure

Transfer Function of Third Order Low Pass Filter

R1=49.9ohm  C1=8.2pF  L1=56nH  R2=150ohm  C2=27pF Matlab Code of Bode Diagram

num=[2443912214.6732];

den=[1 2443912214.6732];

num2=[6.6137566137566*1e17];

den2=[1 246913580.24691 6.6137566137566*1e17];

G=tf(num, den);

H=tf(num2,den2);

T=G*H;

bode(T);

grid on;

title('Third Order Bode LPF Diagram');

Bode Diagram of Third Order Low Pas Filter with Matlab Figure

Cutoff Frequency

When we look at second order (fig 6) and third order (fig 8) bode diagram graphs, we see that the cut off frequencies are same. As a result, we can say that the cut off frequency of total circuit depends on the second order cut off frequency for this case. ## 2 Replies to “Analyze of 3. Order Passive RLC Low Pass Filter”

1. Highland AvenUe Restaurant says:

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