[TenTec] SDR-1000 Product Test available

[Duane - N9DG]

What I think you are seeing is the dynamic range limitation
of 16 bit sampling. The fact that the IMD DR3 dynamic range
is within a few dB of the theoretical limit for 16 bits I
find remarkable. You will also note that the difference in
both dynamic range specs for both 20 and 5 kHz spacings are
essentially identical. Again this exposes the limits of 16
bit sound card sampling. But it also suggests an exceptional
linearity for the QSD. So it appears that most of the
SDR-1000's RX performance limitations are the sound card used
and not the SDR-1000 hardware itself. This was not
unexpected. I also would not be surprised if the 2 kHz
spacing dynamic range performance is also about the same as
the 20 & 5 kHz numbers are.

The reviewers did not adequately indicate or stress
importance that those RX test number results are for a single
16 bit sound card tested. It will be interesting to see how
much better the numbers become when the PowerSDR software is
enhanced to use 24 bits @ 192 kHz sampling instead of 16 bits
@ 48 kHz that it now uses.

Duane
N9DG  

--- Bill Tippett <btippett at alum.mit.edu> wrote:

> http://www2.arrl.org/members-only/prodrev/pdf/pr0504.pdf
> 
>          Nothing to get very excited about yet.  It has the
> worst BDR performance I've seen from any rig in a long
> time (only 93 dB at 5 kHz) although IMD is not bad (86 dB
> at 5 kHz).  BDR is so bad it makes me wonder if there was
> a problem with the rig tested.  I suspect things get even
> worse where the going gets tough (i.e. 1-2 kHz spacings).
> 
>                                  73,  Bill  W4ZV
> 
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