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hi, can anybody help me to design and implement an fourth order butterworth high pass filter in s domain.here are the specs input = 1kHz sine order = 4 fs = 20kHz As = 80dB thanks in advance sid

sid4u wrote: > hi, > > can anybody help me to design and implement an fourth order butterworth > high pass filter in s domain.here are the specs > > input = 1kHz sine > order = 4 > fs = 20kHz > As = 80dB > > thanks in advance If you don't know how to design it, how do you know it's what you need? The frequency into a filter is not usually one of its specifications. I'm pretty sure that As, whatever that means, is not independent of the order, and so can't be independently specified. In the s plane, the poles of a Butterworth filter are uniformly distributed around a circle. Try http://www.maxim-ic.com/appnotes.cfm/appnote_number/1795. Jerry -- Engineering is the art of making what you want from things you can get. ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

"sid4u" <v...@gmail.com> wrote in message news:u...@giganews.com... > hi, > > can anybody help me to design and implement an fourth order butterworth > high pass filter in s domain.here are the specs > > input = 1kHz sine > order = 4 > fs = 20kHz > As = 80dB > > thanks in advance > sid > > You fitst need to deisgn the low-pass prototype. You then need to transform low pass to high pass. What ripple do you need in the passband? If it is 3dB you can look up in tables what the Butterworth polynomial is. Tam

"HelpmaBoab" <F...@yahoo.co.zpc> wrote in message news:2ypSf.6728$J...@news.xtra.co.nz... > > "sid4u" <v...@gmail.com> wrote in message > news:u...@giganews.com... >> hi, >> >> can anybody help me to design and implement an fourth >> order butterworth >> high pass filter in s domain.here are the specs >> >> input = 1kHz sine >> order = 4 >> fs = 20kHz >> As = 80dB >> >> thanks in advance >> sid To the OP: Google is your friend. Some time ago I was researching a similar problem. Google led me to a site with a Java applet that will calculate the coefficients for several types of IIR filters given the specifications you cited. >> >> > > You fitst need to deisgn the low-pass prototype. You then > need to transform > low pass to high pass. > What ripple do you need in the passband? If it is 3dB you > can look up in > tables what the Butterworth polynomial is. > > > Tam > Butterworth has no ripple in either the passband or the stopband. It is "maximally flat". >

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thanks for ur responses.
>"HelpmaBoab" <F...@yahoo.co.zpc> wrote in message
>news:2ypSf.6728$J...@news.xtra.co.nz...
>>
>> "sid4u" <v...@gmail.com> wrote in message
>> news:u...@giganews.com...
>>> hi,
>>>
>>> can anybody help me to design and implement an fourth
>>> order butterworth
>>> high pass filter in s domain.here are the specs
>>>
>>> input = 1kHz sine
>>> order = 4
>>> fs = 20kHz
>>> As = 80dB
>>>
>>> thanks in advance
>>> sid
>
>To the OP: Google is your friend. Some time ago I was
>researching a similar problem. Google led me to a site with
>a Java applet that will calculate the coefficients for
>several types of IIR filters given the specifications you
>cited.
>
>
>>>
>>>
>>
>> You fitst need to deisgn the low-pass prototype. You then
>> need to transform
>> low pass to high pass.
>> What ripple do you need in the passband? If it is 3dB you
>> can look up in
>> tables what the Butterworth polynomial is.
>>
>>
>> Tam
>>
>
>Butterworth has no ripple in either the passband or the
>stopband. It is "maximally flat".
>>
>
>
>
```