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Building a 4 poles filter

GGMM

May 15, 2022
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May 15, 2022
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Hello,

I have assembled 2 filters 2 poles to make one. (Filter 45MHZ 15Khz band filter ref: 45R15AZ)
I have an interesting curve with my nanovna on my homebuild , but I would like to improve the center of the curve to try to have a dish.
What is your best schematic of association of these 2 filters to have a dish in the center
Thank you
 

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danadak

Feb 19, 2021
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"Dish", a flat top ? Or equaripple Cheby ?

Your link takes one to -

upload_2022-5-15_14-47-9.png



Regards, Dana.,
 

GGMM

May 15, 2022
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May 15, 2022
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Hello,
i have found a schematic to try
yes i want a flat top from 44.992 to 45.008MHZ for exemple
cdtfiltre 45 MHZ_1.JPG
 

danadak

Feb 19, 2021
182
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Here is a design tool.

https://rf-tools.com/lc-filter/

Do you have the crystal elements ? The schematic you show is probably
8'th order or higher due to them.

You also do not give all the specs (including loss) needed -

iu


Does it have to be linear phase ?


Regards, Dana.
 
Last edited:

kellys_eye

Jun 25, 2010
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Why a pronounced 'dish' requirement? This isn't 'good' for any reason I can think of when designing filters.....
 
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