MATLAB: How to find transfer function from a difference equation

differential equationsdoit4metransfer function

Hey,,I'm new to matlab.

I have homework says that:- y(n)=0.4142y(n-1)+0.2929x(n)+0.2929x(n-1)

find H(z) ?? Plot the poles and zeros on the z-plan with the unit circle ?

Can Somebody help me ,, Please?? thank You !

Best Answer

This is not a MATLAB question.

Here is some theory:

https://ccrma.stanford.edu/~jos/filters/Z_Transform_Difference_Equations.html

You can certainly plug in those coefficients into tf (in the right way) and it will give you the transfer function.

Related Solutions

MATLAB: Bode Plot Transfer Function

Here you are:

close all
clearvars
s=tf('s')
H=(s^4+s^2+1)/(s^4+2*s^3+3*s^2+4*s+1)
opts = bodeoptions('cstprefs');
opts.PhaseVisible = 'off';
bodeplot(H, opts );
grid on; zoom on;

MATLAB: Transfer analog model to digital one

According to OP's comment. It appears that the term 1/s appeared in exponent by mistake. It is actually being multiplied by the denominator. According following method can be used

You can use c2d function to convert it into discrete. Note that the correct way to define the transfer function is like this

s = tf('s')
sys = 1/(s*(s+1)^3)
sys_dis = c2d(sys, 0.1) % 0.1 is sampling period

Result

>> sys
sys =
 
             1
  -----------------------
  s^4 + 3 s^3 + 3 s^2 + s
 
Continuous-time transfer function.
>> sys_dis
sys_dis =
 
  3.925e-06 z^3 + 4.067e-05 z^2 + 3.83e-05 z + 3.278e-06
  ------------------------------------------------------
      z^4 - 3.715 z^3 + 5.171 z^2 - 3.197 z + 0.7408
 
Sample time: 0.1 seconds
Discrete-time transfer function.

To plot the values

bode(sys_dis) % bode plot
pzplot(sys_dis) % pole zero
step(sys_dis) % step response
impulse(sys_dis) % impulse response

Best Answer

Related Solutions

MATLAB: Bode Plot Transfer Function

MATLAB: Transfer analog model to digital one

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