[Elecraft] K3 2.7kHz filter DSP FC

[Ed Muns]

> Can someone explain to me why with the standard 5 Pole 2.7 
> kHz
> filter the DSP FC = 1.6kHz ?
> 
> Looking at the NORMed DSP for that filter the LO = 0.25 kHz 
> and
> the HI = 2.7 kHz.
> 
> So I would have thought that FC = (2.7 - 0.25) / 2 or 1.225 
> kHz
> say 1.2 kHz.
> 
> Maybe my idea of what FC represents is wrong..
> ----------------------------------
> I don't have a radio, so I'm guessing at what all these 
> number mean, but I think that when you did the average it 
> should have been (2.7 + 0.25)/2 = 1.475
> 
> It's not all the way to 1.6, but closer.

The math is (2.7/2) + 0.25 = 1.60 because Fc, the center frequency of the
filter is half the filter bandwidth plus the frequency of the lower edge.

73,
Ed - W0YK