[Elecraft] Crystal Filter Offset in 4.81, What does it mean?

[Don Wilhelm]

Sorry,  Change the last "passband width" to "sidetone pitch"
My thoughts an fingers got mixed up, and I am old enough to claim a 
"senior moment":-)

73,
Don W3FPR

On 2/6/2014 11:21 AM, Don Wilhelm wrote:
> 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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