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9th December 2014, 20:55 #1
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5th order Butterworth Bandpass Filter Design
Hello,
I want to design 5th order butterworth filter.
I have this parameters;
w1=7kHz
w2=12kHz
Order=5
Type=Butterworth
Bandpass
PRW= 
Which steps can I track?

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9th December 2014, 21:33 #2
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Re: 5th order Butterworth Bandpass Filter Design
Passive or active?
Impedance? Voltage?
Linear or Switched Capacitor blocks or Digital with filter libraries?A best design is easily achieved with good test specs™
A better question deserves a better answer. ™
... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.
... Tony Stewart EE since 1975
 slightly north of Toronto
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9th December 2014, 21:50 #3
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Re: 5th order Butterworth Bandpass Filter Design
How deep is your knowledge?
Do you know the difference between several available design strategies active, passive, cascade design, direct design,...)?
By the way  there is no bandpass of fifth order. The order is determined by the number pole pairs [correction: number of poles] (n=2,4,6..)  and it is not a simple task to design a Butterworth bandpass of order n=4 or n=6.
Are you allowed to use a filter design program? This would be the best and easiest way for designing such a filter.Last edited by LvW; 9th December 2014 at 22:13.
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9th December 2014, 23:07 #4
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Re: 5th order Butterworth Bandpass Filter Design
I think we can assume BPF=LPF and HPF which are implemented by cascade
The order can also be implmented in odd numbers using switch cap block filter chips.
I think the easiest solution uses LTI's 5th order B LPF filter on a chip with adaptation using external RC for HPF, combined using 2 chips and a clock.A best design is easily achieved with good test specs™
A better question deserves a better answer. ™
... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.
... Tony Stewart EE since 1975
 slightly north of Toronto
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9th December 2014, 23:19 #5
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9th December 2014, 23:24 #6
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10th December 2014, 11:36 #7
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Re: 5th order Butterworth Bandpass Filter Design
Of course, you can. However, as a result you will get a 5th order filter having a certain pass band  but it will NOT be a Butterworth bandpass.
So  what do you really need?
   Updated   
In particular, you should clarify if you need a filter with 5 poles or 5 pole pairs (terminology is sometimes confusing).Last edited by LvW; 10th December 2014 at 11:06.
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10th December 2014, 11:42 #8
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Re: 5th order Butterworth Bandpass Filter Design
This is a very powerful filter synthesis software:
http://www.nuhertz.com/software/soft...filtermodule
There is also a nocost lite version:
http://www.nuhertz.com/software/filterlight

13th December 2014, 11:31 #9
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Re: 5th order Butterworth Bandpass Filter Design
Hi,
You need butterworh response then it should not be a LP+HP cascaded and it must BPF only.
If you not worrying about butterworth resposne, go ahead with LP+HP cascaded.
Next, order of filter will be based on your stopband rejection level.

13th December 2014, 17:46 #10
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Re: 5th order Butterworth Bandpass Filter Design
You may choose any criteria for HP,BP,LP and cascaded in any order as long as interference is tolerated by active part. e.g. 10th order by cascading two LTC1062 chips. http://cds.linear.com/docs/en/datasheet/1062fd.pdf
3rd order HPF comes in many std. flavors, Salen & Keys ( see bottom image) MultiFeedback high gain HPF and may be increased in order.
The LTC1062 may also be adapted with external RC parts to make a 5th Order HPF.
Design by Parameters include;
Low side band stop rejection values
slope on low side, ,
Band pass criteria ( gain, minimum ripple, , linear phase, maximally flat amplitude, maximally flat group delay, raised cosine) and then band reject on high side.
slope and phase shift on high side, Q, overshoot, etc.
Active switch cap RC filters may be any n value or order and may be cascade but limited to practical frequencies of circuit such as 10~ 100kHz.
Then I might consider using something like below.
A best design is easily achieved with good test specs™
A better question deserves a better answer. ™
... so include all your acceptance criteria ( values, % tolerance) and assumptions in your question or any design.
... Tony Stewart EE since 1975
 slightly north of Toronto
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