FIR systems

[william g]

1.) I know harbal uses FIR filters, FIR systems have no denominator, so it is always stable
(I like it)

2.) I also know F.F.T. systems, I have got one on a DSP platform, (i like it)

3.) What I would like to know is: a.) what is I.I.R. filters or systems,
b.) what is L.T.I. systems
If you anyone using these tool systems, or if your going to work with them in the future. Please , please i am looking for some knowledge on IIR and LTI systems.


P.S. I understand that Harbal has been upgraded, and i have yet to be sent any mail regarding this
the version 1.5.1. if you could mail me the new version I would be greatful

Thank you

Looking forward to your reply

william

[har-bal]

1.) I know harbal uses FIR filters, FIR systems have no denominator, so it is always stable
(I like it)

2.) I also know F.F.T. systems, I have got one on a DSP platform, (i like it)

3.) What I would like to know is: a.) what is I.I.R. filters or systems,
b.) what is L.T.I. systems
If you anyone using these tool systems, or if your going to work with them in the future. Please , please i am looking for some knowledge on IIR and LTI systems.


P.S. I understand that Harbal has been upgraded, and i have yet to be sent any mail regarding this
the version 1.5.1. if you could mail me the new version I would be greatful

Thank you

Looking forward to your reply

william

William

IIR filters are Infinite impulse response filters. Basically they comprise difference equations that include feedback paths such that the output at sample n is dependent upon what the sample was at
n-1, n-2 etc. They are generally less computationally taxing than an FIR but are less versatile and can suffer from instability and limit cycle issues. In an application like HarBal where you are synthesizing an artibtrary frequency response, implementing it through IIR would be very difficult and impractical. Using minimum phase filter realisations in HarBal is almost equivalent to IIR in any
case. It is basically the IIR filter impulse response trunctated to a finite length of 8192 samples.

LTI stands for linear time invariant which basically means a linear system that has characteristics that do not change with time.

Regards,


Paavo.