Elliptic Filter

Rules | Recent posts | topic RSS | Search | Register | Log in

Elliptic Filter

EDAboard.com Forum Index -> Analog Circuit Design

Author

Message

sec

Joined: 08 Aug 2006
Posts: 81
Location: Canada,QC

14 Sep 2007 22:34 Elliptic Filter

I need help to design elliptic filter !!! I would like to build a bandpass elliptic filter for audio signal. what does a basic circuit look like ? and what are the equations to set the center frequency and to chose the capacitor value ?

renwl

Joined: 26 Apr 2004
Posts: 452
Helped: 22
Location: shanghai,china

15 Sep 2007 6:32 Elliptic Filter

you can use the filter design software such as filter solution.

gowthamn

Joined: 06 Apr 2006
Posts: 34
Helped: 1

15 Sep 2007 15:12 Re: Elliptic Filter

Which filter are u planning to design is it a Digital filter or analog filter?
If u are designing digital filter u can use Matlab and u can design using the fdatool box in matlab with Realization, phase and frequency response.
Cheers
Gowtham

sec

Joined: 08 Aug 2006
Posts: 81
Location: Canada,QC

15 Sep 2007 15:29 Re: Elliptic Filter

no, I what to design an analog filter with high *selectivity
* I don't know if it is the right term

scintillatingstuffs

Joined: 04 Jun 2006
Posts: 34
Helped: 4

15 Sep 2007 20:08 Re: Elliptic Filter

First calculate all ripples tolerable in the passband and stopband through the help of matlab.

Then standard circuits may be available for elliptic filter design. Or look for ICs through Net.

Select parameter values to suit your ripple and gain factors.

sec

Joined: 08 Aug 2006
Posts: 81
Location: Canada,QC

16 Sep 2007 17:52 Re: Elliptic Filter

I don't have matlab, it seem to be useful, isn't it ?

what mean "s" on the equation ?

Sorry, but you need login in to view this attachment

Old Nick

Joined: 14 Sep 2007
Posts: 339
Helped: 36

17 Sep 2007 15:05 Re: Elliptic Filter

sec wrote:

I don't have matlab, it seem to be useful, isn't it ?

what mean "s" on the equation ?

s is the comoplex angular frequency

s=Σ+jω

but you can just use s=jω where j is the sqrt of -1 and ω =2*pi*F

Read some LaPlace transform stuff for a full description

abcyin

Joined: 15 Apr 2005
Posts: 152
Helped: 7

18 Sep 2007 2:47 Elliptic Filter

you can get the filter prototype by filter design software, and then replace the inductor included by gyrator and capacitor, its a easy way to design a elliptic filter.
hope it helps!

andre_teprom

Joined: 07 Nov 2006
Posts: 164
Helped: 11
Location: BRAZIL - Rio de Janeiro

18 Sep 2007 13:29 Re: Elliptic Filter

Try it :

http://www.filter-solutions.com/

It's the best CAD in filter design. It give you : Transfer function, frequency responce, Circuit active, circuit passive, IIR and FIR C code, pole-zero plots, and much more...

enjoy.

+++

northeast1

Joined: 21 Jun 2007
Posts: 145
Helped: 4

08 Oct 2007 6:27 Re: Elliptic Filter

sec wrote:

I need help to design elliptic filter !!! I would like to build a bandpass elliptic filter for audio signal. what does a basic circuit look like ? and what are the equations to set the center frequency and to chose the capacitor value ?

matlab FDA tools

tillu

Joined: 21 Feb 2006
Posts: 15
Helped: 1

08 Oct 2007 13:07 Elliptic Filter

check out book on analog filter design by hueskllman

zhangmingsdu

Joined: 09 Oct 2007
Posts: 1

11 Oct 2007 16:01 Elliptic Filter

use matlab simulation,is it sc filter or...

maninnet

Joined: 25 Oct 2007
Posts: 105
Helped: 2

27 Oct 2007 2:35 Elliptic Filter

here is the routine:

1. figure out the transfer function, which should be normalized.
2. convert the transfer function to signal flow diagram diagram
3. map the diagram into either active rc, gmc, mos c or switch cap of you interest.
4. finally frequency scaling all the component to meet the spec.

filter-solution mentioned by the others is good choice.

raghuram_msc

Joined: 03 Jul 2007
Posts: 100
Helped: 4
Location: Bangalore, India

16 Nov 2007 9:12 Re: Elliptic Filter

Dear All,

An elliptic filter design and realisation is quite complex affair, and if I am not wrong sec is not quite conversant with transfer fuctions and filter synthesis thereof.

Quote:

I don't have matlab, it seem to be useful, isn't it ?

what mean "s" on the equation ?

Dear Mr Sec, I would rather suggest you brushup yur fundas on basic filter synthesis. One more thing, why only Elliptic approximation?? why not little easier implementations like chebyshev/butterworth or easier still LC Filters?? Filter implementation at audio frequencies is not that difficult at all.....

Sai

sec

Joined: 08 Aug 2006
Posts: 81
Location: Canada,QC

19 Nov 2007 21:11 Re: Elliptic Filter

well, a little bit for the challenge and also it take less element for the same "speed"of transition between passband and the stopband

hunter694

Joined: 11 Aug 2004
Posts: 54
Helped: 3
Location: Sweden

20 Nov 2007 18:04 Re: Elliptic Filter

Sec,

Go here for a Master's thesis about Elliptic filter design that I posted before.

/Hunter

songjunjian

Joined: 02 Aug 2007
Posts: 26
Helped: 3

29 Nov 2007 9:10 Re: Elliptic Filter

I think you should search an transfer function , you can do this by software tools, such as fdatools. then you can map the transfer function into circuit.

Manjunatha_hv

Joined: 03 Aug 2005
Posts: 523
Helped: 73
Location: Bangalore-INDIA

27 Dec 2007 7:56 Re: Elliptic Filter

Hello,

Try, Nuhertz Filter Solutions tool it have specific options for Digital & Analog filter synthesi capabilities & even optimizer & Monte-Carlo analysis...
http://www.nuhertz.com/

and
The new fourth edition of Electronic Filter Design Handbook illustrates Elliptic filter design with Filter Solutions.
Author Arthur Williams does an excellent job making Elliptic filter design easy.

I hope this helps you to solve your problem...

---manju---

cheggy

Joined: 03 Jul 2007
Posts: 133
Helped: 3

18 Jan 2008 14:04 Re: Elliptic Filter

Hi, try MicroWave Office - Filter Design Wizard. You'll find it very user-friendly, and after You specify Your filter it'll give you circuit schematic with suggested component values.

peni

Joined: 20 Jan 2008
Posts: 65
Helped: 4

24 Jan 2008 18:19 Re: Elliptic Filter

a good paper ~~

Sorry, but you need login in to view this attachment

peni

Joined: 20 Jan 2008
Posts: 65
Helped: 4

24 Jan 2008 19:16 Re: Elliptic Filter

another good one~~

Sorry, but you need login in to view this attachment

3_1416

Joined: 25 Jan 2008
Posts: 3

06 Feb 2008 6:14 Re: Elliptic Filter

I've found this very simple and old, yet very efficient DOS public domain application many years ago.

Uncompress this file, open a DOS command window and type "RFDESIGN" to start the aplication.

Also included an old version of the PC-ECAP shareware (Yep! Another DOS application!). PC-ECAP is an excellent program to get the frequency/phase response/transient/Return_loss-VSWR of an active/passive filter.

Sorry, but you need login in to view this attachment

ayan_ns

Joined: 16 Feb 2008
Posts: 52

17 Feb 2008 14:26 Elliptic Filter

What kind of filter u r going to design -digital or analog ? u can use Matlab and a free software circuit maker for realization ur ckt. and for better understanding it from theoritical point of view u can see the book of flter designing by Ian Hunter or by G.L.Mettahei

jecyhale

Joined: 19 Feb 2008
Posts: 383
Helped: 37
Location: China

01 Apr 2008 8:01 Re: Elliptic Filter

There are many method in the internet.

muralicrl

Joined: 06 Feb 2008
Posts: 278
Helped: 30

01 Apr 2008 8:37 Re: Elliptic Filter

Hi,

Hereby I am attaching very good material for you to design Digital filters.

Sorry, but you need login in to view this attachment

jimmylin0226

Joined: 10 Jan 2006
Posts: 5

03 Apr 2008 5:29 Re: Elliptic Filter

Does anyone have the experience or good reference to transfer elliptic filter to halfband IIR filter?

Sadegh.j

Joined: 29 Nov 2006
Posts: 629
Helped: 30

03 Apr 2008 15:08 Re: Elliptic Filter

You can do two things, either use a simulator and play with it after getting a basic feel for the filter. The better option is to use the equation for the elliptic filter, have you tried searching the web?

I am sure ADS can help you since it has filters in it.

LvW

Joined: 07 May 2008
Posts: 497
Helped: 103
Location: Germany

07 May 2008 12:32 Re: Elliptic Filter

I feel the time has come to make some general statements on filter design.
For example, just to say “I like to design an elliptical filter” is completely insufficient and nobody can give a substantial answer to such a question.

Instead, the design has to follow some steps in the right order:
1.) Frequency and attenuation requirements
2.) Choice of an approximation (out of at least five alternatives)
3.) Filter order (as a consequnence of steps 1 and 2)
4.) Choice: passiv or active
5.) Selection of technology (opamp, OTA, SC, CC)
6.) Choice of synthesis procedure: Cascade design or direct (ladder simulation ,leap frog, FLF, PRB)
7.) Selection of a specific circuit (Sallen-Key, MLF, several Biquads, FDNR,………)

Did I forget something ?
You see, filter design is connected with several design steps. For example, to build a lowpass of only second order you have at least 20 alternatives.
But, how come to a decision and what governs the choice ? Several aspects, like component availability, cost, power and supply voltage requirements, frequency range, tuning capabilities, accuracy requirements, ………
And don´t think, that the problems rise with frequency; to design an active lowpass for a pole frequency of 10…100 mHz is a big problem.
Perhaps this helps somebody a bit.
Regards.

LvW

Joined: 07 May 2008
Posts: 497
Helped: 103
Location: Germany

07 May 2008 20:40 Re: Elliptic Filter

Ooh yes,sorry, I forgot something - Point 8:

To find one set of component values (out of infinite variations) one can use
- formulas to be found in relevant textbooks, or
- filter design software.

However, one should be aware of the fact that - according to my knowledge - all filter design programs are based only on a very limited number of circuit alternatives.
More than that, as far as filter orders higher than two are concerned, the most powerful circuits (active ladder simulation) are not considered by these programs (with one exception: Filter-Solutions from Nuhertz-Tech.)

LvW

rillyxue

Joined: 03 Jan 2007
Posts: 25
Helped: 1

14 May 2008 4:09 Re: Elliptic Filter

Step1. from system requirement , we choice a best filter type. Step2. from filter spec, compute N and（N round up to an integer）.
Step3. compute a.
Step4. compute sinh a, cosh a.
Step5. compute filter’s poles.
Step6. compute pole frequency and pole quality factors of filter.
Step7. compute stop band attenuation when N round up to an integer.
Step8. get LC-Ladder prototype.
Step9. compute filter’s transfer function.
Step10. synthesize parameter of every stage from filter transfer function.
Step11. compute filter amplifier parameters.
Step12. filter amplifier design.
Step13. complete filter design basic .
Step14. filter phase compensation design.
Step15. stability analysis under large signal.
Sdtep16. filter auto calibration design.
Step17. done.

Added after 2 minutes:

you may should do filter phase compensation design, i surgest you using active compensation.

EDAboard.com Forum Index -> Analog Circuit Design

Page 1 of 1

All times are GMT + 2 Hours

Abuse
Administrator
Moderators

sitemap