Tansfer Function To a Difference Equation

[1bob1]

Hi,

This is a question relating to DSP. I wasn't sure what section to put it in. (move it if you so wish)


I have the transfer function:


0.5 - 0.3 z-1
------------- = H(z)
1 + 0.25 z -1


I need to obtain a difference equation ( i.e in the form y(z)= )


My problem is I cant find in text books, or on the web, a simple explanation for converting said transfer function to a difference equation. (please note this is a difference equation not a differential equation).


I found the following link to be the most useful thing so far, (if you explore the site a bit). But I still don't understand how the process is done.
[ http://ccrma.stanford.edu/~jos/fp3/Z_Tr ... tions.html ]


Thanks for any help anyone can provide,


Bob

 

[mmm4444bot]

It looks like there might be some missing grouping symbols, in the way that you typed the definition of H(z).

Clearly, the expression 1 + 0.25 z - 1 simplifies to 0.25 z .

Are you trying to state the following?

H(z) = [0.5 - 0.3(z - 1)]/[1 + 0.25(z - 1)]