First order IIR filter

>
>  - Why it is impossible to have sex in the middle of the Red Square in 
>Moscow?
>
>  - Because every idiot bystander will be trying to give you the 
>invaluable advice of how to do it.
>
>
>VLV
>
%%%

Somebody might even record that and put it on youtube..

On Feb 25, 1:36 am, Glen Herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> steveu wrote:
> >>Rohit wrote:
>
> (snip)
>
> >>>I googled a lot about IIR filters but nowhere I could find this
> >>>formula.
> >>Yes it is an IIR filter.  It might be that it is used more by
> >>statisticians than EE/CS so it has a different name.
>
> (snip)
>
> > Huh? I would have thought the basic single pole LPF was about the most
> > used filter for statisticians, EE, CS, DSP, or just about any other
> > denomination of folks who filter that I can think of.
>
> I have never seen the term "IIR filter" in a statistics book,
> or anything related to poles.
>
> The same filter under a different name.
>
> -- glen

They use the terms Autoregressive Moving Average (ARMA) or just AR
lets say.

Hardy

On Feb 24, 11:32&#4294967295;am, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
wrote:
> &#4294967295; - Why it is impossible to have sex in the middle of the Red Square in
> Moscow?
>

I thought it was because the communist regime neutered all the men
rendering them all impotent

On Feb 24, 6:57�pm, buleg...@columbus.rr.com wrote:
> On Feb 24, 11:32&#4294967295;am, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
> wrote:
>
> > &#4294967295; - Why it is impossible to have sex in the middle of the Red Square in
> > Moscow?
>
> I thought it was because the communist regime neutered all the men
> rendering them all impotent


Your formula does not look right, for example;

> Output = ([1/(2^n -1)]*input) + ([2^n/(2^n -1)]*PreviousOutput)

will be unstable because the coefficient applied to the previousOutput
is > 1.

What is much more common is;

                       2^-n
             H(z) = ---------------------------------
                    [1 - (1- (2^-n))*Z^-1  )]



The reason this is common is that 2^-n is just a shift and therefore
the the implementation does not require a multiplier (and if you are
slightly clever, the shift can be shared between numerator and
denominator). The drawback is that the cutoff frequency is very
coarsely quantized, depending on n. It is also nice that the DC gain
is 1.0 by construction.

Bob Adams