[sdiy] Steiner VCF as allpass?

[Yves Usson]

This a repost because I had problems with my sendmail and
I am not sure it went through the first time ! Sorry for the duplicate 
if any !

Hi Nils

Yes it does, in the schematic at my site you can se a 4 positions x 2 
circuits rotary switch.
With it one can switch between lowpass (pos 1), bandpass (pos2), 
lowpass+highpass (pos 3),
and hihpass (pos 4).

If you need to have a true allpass (that is lowpass+bandpass+highpass) 
you must use
a 4 positions x 3 circuits rotary switch and do the proper connecting, 
that is :
- the common poles of the 3 circuits connected together,
- lowpass connected to the 1st position of circuit 1 and to the 3rd 
position of circuit 3,
- bandpass connected to the 2nd position of circuit 1 and to the 3rd 
position of circuit 1,
- hipass connected to the 4th position of circuit 1 and to the 3rd 
postion of circuit 2...

I Hope this helps


Le mercredi, 21 avr 2004, à 14:51 Europe/Paris, Nils Pipenbrinck a 
écrit :

> Just a short question.....
>
> The Steiner VCF can run as highpass, lowpass and bandpass by injecting 
> the signals at different places into the filter. (nice, need to add 
> that to my other sallen key vcf's when i find some time).
>
> Does it do allpass if I inject the same signal into low, high and band?
>
> Thanks,
>  Nils
>
>
-------------------------------------------------------------
Yves Usson

Lab. TIMC UMR5525 CNRS
Institut d'Ingéniérie et de l'Information de Santé (IN3S)
Faculté de Médecine
Domaine de la Merci
38706 La Tronche cedex

email : yves.usson at imag.fr, yves.usson at ujf-grenoble.fr

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