Can anyone tell how to design elliptic filter

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shady205

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Hello friends...

Can you help me in designing an elliptic filter. I'm planning to do a switched capacitor Elliptic Ladder Filter for an order 5.

I had uploaded the passive structure and the corresponding signal flow graph.

Thanks in Advance
Bhagath

Added after 58 minutes:

uploaded files
 

Hi Bhagath,

in the following I can give you two references, which very good matches your problem. In both cases, elliptical S/C filters are designed based on a SFG diagram which is identical to yours.

1.) Jacobs, Allstot, Brodersen, Gray: Design Techniques for MOS switched capacitor ladder filters, IEEE Trans. Circuits ans systems, CAS-25, No 12, Dec. 78, page 1014

2.) Brodersen, Gray, Hodges: MOS Switched-Capacitor Filters, Proceedings IEEE, vol-67, No 1, Jan. 1979, page 61

Perhaps this helps.
LvW
 

    shady205

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thanks LvW..

i do have those papers but what i need is ...

i found the Transfer function from the above passive network and i want to equate the corresponding Transfer function to the standard elliptic (lowpass ) prototype for passive elements.

by comparing these two for the same transition ratio and ripple we get the values of the corresponding L and C values. But i don't have the standard elliptic prototype for passive elements which is in the below following books..

R.Saal Handbook of filter Design AEG-Telefunen, Berlin 1979.

D.S.Sticht & L.P.Huelsman Direct determination of Elliptic network functions Int J. Comput Elec Eng Vol 1 pp 272-280 1973

A.L.Zverev Handbook of Filter synthesis Wiley New york, 1967.

if u have any information regarding the Elliptic prototype for passive elements just let me know...

Thanks
Bhagath
 

Hi Bhagath,

I can recommend a design program for passive filters (including elliptical response) to you which you can download for free:

Look at AADE.com

I hope this can help you designing the network
 

but i need to design in Cadence spectre..
and i need to design an analog elliptic Ladder filter
 

Now I am confused, cause I do not see your problem.
The program I have mentioned (AADE) gives you the values for the components (L, C and R) to be used in a ladder topologie and establishing an elliptical response.

What do you still need ?

LvW
 

i need to design an elliptic filter for the following specification..

Ripple = 0.4dB

Stop band gain = -36 dB

transition ratio (Fs/Fc) =1.25

Fc (Corner Frequency) = 40K Hz

Order = 5

Fs = 50K Hz

Fclk = 2.2M Hz
 

Enter all these data (excluding the clock) into the program AADE and it gives you the desired analog ladder structure.
Than, you have to convert it into a S/C network according to the procedure which is described, for example, in the documents I have mentioned before.

LvW
 

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