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#### Phil Newman

- Jan 1, 1970

- 0

In a filter I've designed, I have a series LC with additional

reactance, X, which gives a transmission zero in the filter.

How can I absorb the reactance into either the L or the C or both?

In a simple series LC, the reactance of the product at resonant

frequency is 0, so

jX (reactance) = jwL - j/wC = 0

from which you get

w^2 = 1/LC

however, with the additional reactance (which is frequency invariant -

i.e constant)

jX = X + jwL - j/wC = 0

the value of X, w, L and C are known.

I'm not entirely sure where i'm supposed to go with this though!

the value of reactance/susceptance in the series arm is -0.865

the value of inductance is 5.406H (this is normalised to one radian)

the value of capacitance is 0.18F (again normalised)

resonance is measured at 0.7130/1.404 (normalised, it's a band-pass

filter)

If you can help me make sense of this apparently easier algebra in

which i'm missing something, that would be great!

Phil