[Lowfer] That filter can't be right!!!

[Bill Ashlock]

Gents,

I spend about 2 hours tonight reviewing how these filter tables work. I just 
looked at Lyle's 63uh-1.8nf-63uh filter and it looks like the 1.8nf 
capacitor should be 18nf. Using the table and scaling equations for a 50 
ohm, .25db ripple, N=3, Chebyshev filter, for a cutoff freq of 232k, the 
inductors are 63uh and the capacitor between then to gnd is 18nf, not 1.8nf. 
I set this up in Psipe and the plotted frequency response with 50 ohm source 
and load resistances and this perfectly matches the expected response. Then 
I changed the capacitor to 1.8nf and the response became totally whacky! Now 
it's back to the bench. Results tomorrow.

Bill


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