[Elecraft] K3S vs. K3

[Joe Subich, W4TV]

On 2015-05-16 9:33 AM, Mike Harris wrote:
 > It has so far been assumed that the KIO3B somehow has an analogue to
 > digital conversion function (sound card) feeding the USB interface.

Looking at the current K3 schematic, there is no *digital* connection
between the DSP board and the KIO3. Since the KIO3B is a *replacement*
for the current KIO3, I expect the USB sound function is nothing more
than an off the shelf USB Audio CODEC chip (e.g. TI PCM-2902) fed from
"Line Out" as is the case in the other rigs with USB Audio.

> Looking at the K3 block diagram shows a mysterious KDV3 (Dig. Audio)
> within the DSB environment. KDV3 nomenclature would lead one to
> assume it was a module of some sort.

I doubt that the DSP engine has the horsepower to provide a separate 
isochronous USB audio stream (and identify as a USB CODEC) even if
there were a USB connection from the DSP board (via the RF board) to
a USB hub on the KIO3B.

73,

    ... Joe, W4TV


On 2015-05-16 9:33 AM, Mike Harris wrote:
> It has so far been assumed that the KIO3B somehow has an analogue to
> digital conversion function (sound card) feeding the USB interface.
>
> Looking at the K3 block diagram shows a mysterious KDV3 (Dig. Audio)
> within the DSB environment.  KDV3 nomenclature would lead one to assume
> it was a module of some sort.  I've so far not been able to determine
> from the alphabet soup on the DSP board schematics where a KDV3 might
> interface with the DSP.  This might offer a clue as to how the digital
> audio presented on the USB interface is derived.
>
> Sherwood has previously commented unfavourably on the audio quality of
> the LINE OUT signal.  This has lead to the general acceptance that the
> LINE OUT level should be limited to 8-10.
>
> When the KIO3B module manual becomes available questions might be
> answered.  Or maybe, someone in the know might offer enlightenment.
> Enquiring minds and all that.
>
> Regards,
>
> Mike VP8NO
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