[SOLVED] Even order Chebyshev filter design doubt

[viper_iv]

I was trying to design a type-I Chebyshev filter but have a single doubt about the element values in the LPP tables.

The odd order coefficients always end in a 1 (which means the load is normalized to 50 Ohm) but the even order values vary with the ripple (e.g. 1.9841 for 0.5 dB ripple and 5.8095 for 3 dB).

Does this mean I should treat these final values as impedances??? And if so, how can I match them to 50 Ohm?

Thank you for your attention.

 

[viper_iv]

I'm not using Matlab, the only platform I actually have access to is Octave, but I was trying to do the calculation by hand.

 

[flyhigh]

The minimum of the first ripple for even mode Chebyshev filters falls on DC for LPP. Therefore, it can be produced with resistive divider only. This is why you get different values of the coefficient when varying a ripple value. The resistance of one of the terminations must change from 50 Ohm to provide power loss that effectively creates a ripple dip.

If your goal is to make LPF, then avoid even order.