Transfer Function with Z Domain.

Hi There. I have to obtain a z domain transfer function of 1khz low pass filter to implement this in microcontroller. I heard that its easy to obtain transfer function with designing a fir filter in Matlab. Help please :(

Answer 1

[Wayne King]

If you design an FIR filter in MATLAB, then you have the Z transform coefficients (the coefficients of the polynomial in z^{-1}).

For example: Assume your data is sampled at 10 kHz. The cutoff frequency is 1 kHz, which in normalized frequency is 0.2\pi radians/sample. Design an order 20 FIR filter using the window method.

     Wn = 0.2;
     b = fir1(20,0.2);
     % view magnitude response
     fvtool(b,1,'Fs',1e4)

The vector of coefficients, b, are the terms of the polynomial in z^{-1} for n = 0,1,2,.... 20

You can design FIR filters in many ways, not just using fir1().

[Erdem]

Actually I don't know much about the filters or Matlab. This is my graduate thesis.And i don't have much time :( What i know is embeddding a discrete transfer function (z domain) into a microcontroller. But I don't know how will i obtain a z domain transfer function of a 1 Khz low pass fir filter. My lecturer said that its easy with Matlab but thats all :(

[Wayne King]

I just told you how.