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I am designing a LC low-pass filter for reactive load(Combination of capacitor and Resistor). I want to design 3rd order butterworth filter in order to filter out all the high frequency component present in amplified PWM signal. My switching frequency is 2MHz and desired output signal frequency is 300KHz. Therefore the cut-off frequency of designed filter will be 300KHz. I can't use computer application for filter designing because it always deals with resistive load but in my case the load is reactive. Therefore i have derived transfer function for T-section LC filter and i want to calculate components value for required cut-off frequency of 300KHz and damping factor of 0.7. How to calculate the values of L1,L2 and C1? Due to the presence of capacitor at load side, transfer function has four poles and one zero.