Need Help in Analog filter Design Tool.

[EMitter]

Hi all,

I am using Analog filter design tool to design Active filters , while using this tool i got some of the doubts that how to adjust the parameters to get the better filter response from the design.

Tool link::https://www.analog.com/designtools/en/filterwizard/#/type

Parameter consideration :: Stop band DB , frequency and also the filter response adjustment to select order ,filter type.

Please provide help on this.
Thank you,

 

[JimB]

Your question is rather broad, can you refine it to describe an exact problem?
What is the filter that you are trying to design, what is its application?

JimB

 

[EMitter]

Hi JimB,

suppose say like i need to design low pass filter having a cuttoff frequency 150khz and a 4th order 2stage.
I am having the confusion in selecting the stopband DB and also stopband frequency . These parameter affects the filter response curve.
my question is how to get better response curve from filter design by choosing the stopband and stopband frquency?

 

[simonbramble]

It depends on what you want your passband response to look like. A Butterworth filter will have really flat passband response, but fairly relaxed roll off. This is good for audio applications where passband ripple equates to distortion (kindof). If you want faster roll off, then a Chebyshev is the one to go for, but this has ripple in the passband. These are good if you just want to pass one frequency.

Then there is the elliptical filter, whose roll off is moderate, but it delays all the frequencies by a constant amount, so is good for filtering square waves, but you don't want ringing on the rising and falling edges.

I would go with a Butterworth as this is the most common and more of a classic type of filter
this might help:
http://www.simonbramble.co.uk/techarticles/active_filters/active_filter_design.htm

 

[JimB]

cuttoff frequency 150khz

OK

I am having the confusion in selecting the stopband DB and also stopband frequency

This should be part of you initial requirements specification.
You need to define these along with the cutoff frequency.

a 4th order 2stage

This should come AFTER the cutoff and stopband have been specified, not before.
This is what you need to achieve the required performance, not what you use to define it.

JimB

 

[EMitter]

okay thats i got the solution for my question.