Plotting a filter from it's transfer function

[Emil09]

I'm trying to figure out how to plot the response of discrete time filters based on their transfer functions. For example, if I have the expression of a filter's transfer function, how do I go about translating that into something I can input into Matlab?

 

[MrAl]

Hello there,

Give us an example of your transfer function and we can probably help with this.

 

[Emil09]

Hello there,

Give us an example of your transfer function and we can probably help with this.

Here's the transfer function:

**broken link removed**

And here's where I'm starting in Matlab:

**broken link removed**

This returns an error due to a zero vector. I understand that the vectors must be nonzero but as you can see from the transfer function, I need two of the coefficients to be zero.

 

[misterT]

Try:

num = [0.094, 0.3759, 0.5639, 0.3759, 0.094];
den = [1, 0, 0.486, 0, 0.0117];
sys = filt(num, den);
bode(sys)

 

[Emil09]

Try:

num = [0.094, 0.3759, 0.5639, 0.3759, 0.094];
den = [1, 0, 0.486, 0, 0.0117];
sys = filt(num, den);
bode(sys)

Matlab syntax is painful when you are used coding with C.

It works! Thanks! When I looked at your post I immediately thought that I would get the same error message about vectors having to be nonzero but ... not this time!