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5th order LC filter with inf. RL and near zero Rs (Read 2377 times)
neoflash
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5th order LC filter with inf. RL and near zero Rs
Nov 29th, 2015, 7:52pm
 
Most filter design handbooks are about filters with finite RL and RS. I am just wondering whether there is a cheat sheet to design filters with capacitive load and low impedance driver.

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Neo
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nrk1
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Re: 5th order LC filter with inf. RL and near zero Rs
Reply #1 - Dec 5th, 2015, 3:02am
 
With zero Rs and infinite RL, you will have a lossless(=undamped) network with poles/zeros on the imaginary axis. One of the resistances has to be non-zero. In that case, you can design singly terminated ladder filters. Singly terminated prototypes are also available, or you can solve the nonlinear equations for the component values in matlab or a symbolic solver.
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neoflash
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Re: 5th order LC filter with inf. RL and near zero Rs
Reply #2 - Dec 7th, 2015, 12:17pm
 
Thanks for pointing out this will make lossless network. I meant the source impedance should be quite low.

I tried to fine some singly terminated prototypes for LC ladders. Could you please suggest some good references?

nrk1 wrote on Dec 5th, 2015, 3:02am:
With zero Rs and infinite RL, you will have a lossless(=undamped) network with poles/zeros on the imaginary axis. One of the resistances has to be non-zero. In that case, you can design singly terminated ladder filters. Singly terminated prototypes are also available, or you can solve the nonlinear equations for the component values in matlab or a symbolic solver.

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loose-electron
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Re: 5th order LC filter with inf. RL and near zero Rs
Reply #3 - Dec 7th, 2015, 12:21pm
 
http://www.amazon.com/Handbook-Filter-Synthesis-Anatol-Zverev/dp/0471749427

Zverev is the bible - pre dates computers and spice.

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