Filter design software recommendations

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#1
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Hey ho, what do you know?

 

I have a little personal project where I need to make an active bandpass filter, 6dB or 12 dB rolloff.  Highpass of about 2Khz and low pass of about 4Khz.

 

 

Input will be from a simple microphone with an on board op amp preamp.

 

Planning on using TL084 or even LM324...depends on whats sitting in the bins...

 

Power supply will be 12-14vdc from car.

 

The output of the filter will be rectified and used to trigger an 8pin AVR.

 

 

Ok, so theres the basic electronic specs.  What I was wondering what folks are using these days to design filters.  I haven't used a filter design software kit in a while so hence my question.

 

Cheers,

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

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Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Glass breakage detector?

 

Keys to wealth:

Invest for cash flow, not capital gains!

Wealth is attracted, not chased! 

Income is proportional to how many you serve!

If you want something you've never had...

...you must be willing to do something you've never done!

Lets go Brandon!

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ki0bk wrote:

Glass breakage detector?

 

Lets not worry about the application.  Thats how threads become more convoluted than need be.

 

JIm

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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Google Sallen Key Filter calculator, and there are a bunch of on-line Fc, R, and C calculators.

Some just crank out the values.

Some plot the filter's transfer characteristics for you, also.

 

I think this is a good general purpose Butterworth filter that is easy to implement with an op-amp and 2 R's and 2 C's for a decent 2nd order filter.

It works.

You can cascade a couple of stages to get the degree of filtering you need.

With a dual op-amp chip that gives you a 4th order filter.

With a quad op-amp chip you will spend a lot more time laying out the PCB than you will designing the filter!

 

Don't forget to protect your power supply from "Load Dump" voltages.

 

JC 

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jgmdesign wrote:
Lets not worry about the application. 

[wisper mode]Ok Jim, no problem, I understand[/wisper mode]

 

I've not tried lately, but TI has an online filter app here: https://webench.ti.com/filter-de...

Hope it helps.

 

Jim

PS: I have some of those resistor/cap assortments, in 0402, 0603, or 0805 if you need a few PM me.

 

 

Keys to wealth:

Invest for cash flow, not capital gains!

Wealth is attracted, not chased! 

Income is proportional to how many you serve!

If you want something you've never had...

...you must be willing to do something you've never done!

Lets go Brandon!

Last Edited: Thu. Sep 24, 2020 - 03:14 PM
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ki0bk wrote:
PS: I have some of those resistor/cap assortments, in 0402, 0603, or 0805 if you need a few PM me.

 

Thanks, but this is going to be a through hole gizmo made on perfboard. It's a temporary thing.

 

 

DocJC wrote:
Don't forget to protect your power supply from "Load Dump" voltages.

Not really caring.  But good point.

 

I am trying Microchips Filter Lab, and Analog Designs online filter creator.  The TI tool seems ok.  Will do a comparison and see how far the designs vary from one another.

 

Jim

 

 

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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DSP ... ?

 

cheeky

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awneil wrote:

DSP ... ?

 

cheeky

 

LOL!

 

I do not have any DSP stuff to use, and by the time I figure it all out I will not need the thing anymore

 

Jim

I would rather attempt something great and fail, than attempt nothing and succeed - Fortune Cookie

 

"The critical shortage here is not stuff, but time." - Johan Ekdahl

 

"Step N is required before you can do step N+1!" - ka7ehk

 

"If you want a career with a known path - become an undertaker. Dead people don't sue!" - Kartman

"Why is there a "Highway to Hell" and only a "Stairway to Heaven"? A prediction of the expected traffic load?"  - Lee "theusch"

 

Speak sweetly. It makes your words easier to digest when at a later date you have to eat them ;-)  - Source Unknown

Please Read: Code-of-Conduct

Atmel Studio6.2/AS7, DipTrace, Quartus, MPLAB, RSLogix user

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try 

https://tools.analog.com/en/filt...

or

https://www.ti.com/design-resour...

 

I don't always use "their" parts, others work well if they have similar GBW specs.

Power supply will be 12-14vdc from car.

Yes, you WILL need a filter  :) 

Enjoy your color organ, and getting years more use out of those 8-track tapes.

 

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!

Last Edited: Thu. Sep 24, 2020 - 04:55 PM
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ki0bk wrote:

Glass breakage detector?

 

squeak sniffer?  laugh

Letting the smoke out since 1978

 

 

 

 

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"Dare to be naïve." - Buckminster Fuller

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Prefer Sallen-Key these days. Two pole high or low pass filters are pretty easy. Lots of design pages out there. Maybe even TI. TI has an excellent app note on Sallen-Key filters.

 

West Coast Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!