[sdiy] simple 8k lowpass for ADC?

[Csaba Zvekan]

Hi Dan,

I prefer this little piece of software from Texas Instruments. You can  
download it for free . It runs under Windows or on a MAC in a   
VirtualBOX session.

http://focus.ti.com/docs/toolsw/folders/print/filterpro.html

hope this was useful to you.

Csaba

On Jul 20, 2009, at 8:15 PM, Dan Snazelle wrote:

>
> i am putting audio ( a full track with vocals)  through an 8bit  
> converter. it sounds fine until the vocals get close to  
> sibilance...this
> seems to overload the converter and make the sibilance far far worse  
> to the point of almost white noise.
>
> now when i simply put an eq on the track in Logic FIRST i dont have  
> this issue.
>
> so i would love to build a simple filter into the circuit but dont  
> know what kind to use.
>
> in Logic I am using a roll off which kills everything above 8-10 k  
> (not a very steep curve)
>
>
> with this on there is no issue with the ADC0820 based circuit....and  
> i am NOT overloading the ADC
> as far as levels or voltage go. so this must be an aliasing issue as  
> the problem only arises when
> i sweep the sample rate toward lower clock rates.
>
>
> SO....i tried using simple RC filters but they are not really  
> working out too well.
>
>
> anyone have any advice on the kind of filters they use on an ADC?
>
> or maybe a homebrew switched cap filter i could clock off the clock?
>
> thanks
>
> (keep in mind this is meant to sound dirty anyway...just not crappy)
>
>
>
>
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