[Elecraft] [K3] what audio passband should I expect in TX DATA/DATA A mode?

[Matt Zilmer]

Hi Pf,

Most tone modes operate at an offset from carrier frequency, so that
the audio frequencies of interest are more or less cenetered in the
filter passband.  I believe the JTx modes are already in the 1200 to
1500 Hz range so no offset is required.

The crystal filter being used only restricts the bandwidth of the RX
chain (1st IF).  The DSP imposes its own audio filtering on the
baseband, and that's what you're seeing as rolloff below ~300 and
above ~3500 Hz.

73,
matt
W6NIA

On Sun, 23 Aug 2015 19:03:21 +0200, you wrote:

>
>Hello,
>I'm dabbling with wsjtx, and I see that my rx audio has some definite roll
>off at <300 Hz and >3500 Hz. Selected filter is the 12 kHz one, and
>width is set to 4 kHz. Audio soundcard is the Numark studio-io, but I
>also saw this with an el-cheapo adapter. 
>Also, I see the same roll-off in fldigi, so the final application should
>not matter. 
>Am I doing something wrong? What should be the audio passband available
>at line out connector?
>
>Thanks
>
>Pf
Matt Zilmer, W6NIA
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