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Design >> Analog Design >> 5th order LC filter with inf. RL and near zero Rs
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Message started by neoflash on Nov 29^th, 2015, 7:52pm

Title: 5th order LC filter with inf. RL and near zero Rs
Post by neoflash on Nov 29^th, 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.

Thanks,
Neo

Title: Re: 5th order LC filter with inf. RL and near zero Rs
Post by nrk1 on Dec 5^th, 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.

Title: Re: 5th order LC filter with inf. RL and near zero Rs
Post by neoflash on Dec 7^th, 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 5^th, 2015, 3:02am:

Title: Re: 5th order LC filter with inf. RL and near zero Rs
Post by loose-electron on Dec 7^th, 2015, 12:21pm

http://www.amazon.com/Handbook-Filter-Synthesis-Anatol-Zverev/dp/0471749427

Zverev is the bible - pre dates computers and spice.