S56A:
>Flex-radio SDR with Taylor QSD has
also reached the hardware limit.
Not so. The present limit is determined
by the Delta 44 soundcard rather than the QSD,
and BTW it's Dan Tayloe N7VE (not Taylor).
The HPSDR Janus project is a homebrew
project to develop a better A/D and D/A than the
present M-Audio Delta 44 soundcard being used :
"The bake-off of the A/D converters is complete and the
clear winner is the Cirrus Logic CS5381. The chip yielded
a spectacular -160dBm (11Hz bandwidth) noise floor and
120dB dynamic range."
http://hpsdr.org/janus.html
Until higher performance A/D's than the
Delta-44 become available, the ultimate limit
of the present QSD is unknown. Even as it stands
using the Delta-44, the SDR-1000 had the highest
2 kHz IMD performance ever measured by ARRL
(October QST).
The 16 bit A/D you mentioned would
not even allow the current dynamic range of the
Delta 44 (24-bit) , and it would be MUCH more
expensive. Rather than direct conversion at RF,
Flex's approach is likely to be much more
affordable to hams.
73, Bill W4ZV
_______________________________________________
CQ-Contest mailing list
CQ-Contest@contesting.com
http://lists.contesting.com/mailman/listinfo/cq-contest
|