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How to design a bandpass active filter?

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fedejofa

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Filter Design

Hi, im in a robotic proyect and im trying to make a good bandpass active filter.
the problem is how to design it...apart from adjusting the values for the frequency, Q, etc.
For example, last filter we have seen that didnt respect the open loop margin phase the opamp requiered.
How could i add these constrain when im designing.
Using spice, should i make a open loop circuit and a close one?
What sofware u use for design..? and for these case? any recommendation?

thx and, just in case, sorry for my english.
Greetings.
Federico
 

Re: Filter Design

Hello fedejofa :

We have no clue about the spec here.
But first step is usually table look up for
appropriate filter order.
And then find proper circuit to realize it.

Filter realizable by OPamp can be found in text
books like "operation amplifier circuits"
or "analog integrated circuit design"
Those prototypes are generally derived assuming
no significant phase delay due to OPamp.

Once the thing gets non-ideal, we might need to tune the R,C
values. One thing worth trying is to use "optimizer" in ADS.
Faster than SPICE if tuning is inevitable.

Good Luck,
 

Re: Filter Design

A easy way is to use a filter program.
A good usable program is "Filter Pro".
**broken link removed**
It's very practical oriented because you can also tune the tolerance of capacitances and resistors.

by Gomez
 

Re: Filter Design

hey..... u want to design a filter its not clear that whether it is active or passive but if u want to make it more responssive ....u use active one and make it with Op-amps...and check the phase margin and magnitude one with Bode plot of filter and check whether it is accurate as per ur specification.:|
 

Re: Filter Design

hr_rezaee said:
Hi
use "filter solutions".
regards

you will find this great program at

**broken link removed**

A trial version is available..
 

Re: Filter Design

aomeen said:
hr_rezaee said:
Hi
use "filter solutions".
regards

you will find this great program at

h**p://www.filter-solutions.com

A trial version is available..

yes
it is great program.
it can design active, passive, Tx line, Switch Cap and digital filters.
regards
 

Re: Filter Design

Digital filters are nowadays available in single IC package. Try them and it will eleminates most of the comlicated business out of ur project.
 

Re: Filter Design

riku said:
hey..... u want to design a filter its not clear that whether it is active or passive but if u want to make it more responssive ....u use active one and make it with Op-amps...and check the phase margin and magnitude one with Bode plot of filter and check whether it is accurate as per ur specification.:|
Hi again, firstly, thx for all the replies and the suggestions.
i will try to explain better.
Im planning in designing a good active filter...by using op-amps. But as i am using a feedback system (the op-amps).. i got to check, by using nyquist stability 'criterion' that my filter is stable. Know software for that kind of design? Can i use spice in that kind of things?

I hope i helped understand my question.
thx again.
 

Filter Design

Hi
filter solutions can plot time response, freq response, pole-zero, transfer function, and Reflection Coefficient.
you can set parameter of your non-ideal op amp and so on.
regards
 

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