Arnie,
Think about it this way -- take a filter width of 1500 Hz and a sidetone
pitch of 600 Hz.
If you center the passband at 600 Hz, the upper passband limit will be
at 1350 Hz, but the lower edge will be 150 Hz into the opposite sideband
(single signal reception goes "bye-bye").
The proper position if the passband is to place the lower edge at about
100 Hz, and the upper edge will extend to 1600 Hz.
That is true for any passband that is greater than 2 times the passband
width.
73,
Don W3FPR
On 2/6/2014 10:14 AM, Arie Kleingeld PA3A wrote:
Lyle,
What are you saying here?
The DSP filtering as a second IF would do (and I quote you) a
/terrible/ job. :-)
73,
Arie PA3A
Lyle Johnson schreef op 5-2-2014 16:35:
<snip>
The "center of the passband to the nominal pitch value" only occurs
at higher pitches and/or narrower passbands.
Think about the case where you have 1.5 kHz width selected and a
pitch of 500 Hz. You defintely do NOT want the center of the filter
and the pitch to be equal,or you'd have /_terrible _/opposite
sideband suppression.
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