[Elecraft] KX3 I/Q output and band width

[gt-i at gmx.net]

Walter,
thanks for the pointer. Will give it a try. Not sure how to combine the
two, lets see.
73 Gernot

Am 04.02.2020 um 23:52 schrieb Walter Underwood:
> You actually have 22 kHz of in-phase signal and 22 kHz of quadrature signal
> on the stereo output. You can combine those to get 44 kHz of bandwidth.
>
> More info here:
>
> https://en.wikipedia.org/wiki/In-phase_and_quadrature_components
>
> wunder
> K6WRU
> Walter Underwood
> CM87wj
> http://observer.wunderwood.org/ (my blog)
>
>> On Feb 4, 2020, at 2:45 PM, gt-i at gmx.net wrote:
>>
>> Hello,
>> for a long time I just haven't looked into the details, but now I did
>> and I'am confused.
>> When I plug it into a soundcard it appears to show the current station
>> in the center of the display, to my understanding the center of the
>> display is the half of the sampling frequency of the sound card.
>> This ist at least confirmed in the manual pg. 26 (Rev C5).
>>
>> When I sample the I/Q signal by myself, the same signal appears at the
>> lower end of my spectrum.
>> Now it looks like I'm not getting the full bandwidth sampled? With fs of
>> 44.1kHz I can only see 22kHz of bandwidth after FFT.
>>
>> So, according to many articles I read about FFT, the resulting bandwidth
>> is always fs/2. So how can we see 44kHz of spectrum on a 44kHz sound
>> card? I'm confused...
>>
>> 73 Gernot DF5RF
>>
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