[K3] RE: [Elecraft] How do you measure filter offset

[Tom W8JI]

>        It actually doesn't matter beyond about 30 dB down 
> ina roofing
> filter...the DSP filters handle things beyond that.
>
>>Two points are entirely
>>sufficient to **center** the filter's 6 dB bandwidth, 
>>which was the
> question
>>asked.
>
> I don't think -6dB bandwidth was the question, but rather 
> how to measure the
> filter. Whatever -- a single number description is quite 
> limited.


If I wanted to center and match a typical SSB or CW filter 
for passband centering,  I'd use something like 5 or 10 dB. 
I wouldn't match them at a higher attenuation because it 
really doesn't mean anything and can be very misleading and 
cause the actual useful centers to be misaligned.

It really should just be at some attenuation that is much 
greater than the ripple amount, but not so far down on the 
skirt it is meaningless for the actual passband.

73 Tom