Lyle:
Indeed.
Dan:
I do not recall having ever said a single thing about removing DDS chips
from a circuit board. I do however see great promise for a removable
I/Q clock generation module. It has been my experience in watching Flex
do business over the past two years, and Elecraft in the years before
and continuing, that if a widget comes along that promises to make
things better and the justification is strong enough, people do it.
On the need for high conversion and the management of multiple
conversion stages: until the measurements we are getting from
independent labs/testers show otherwise, I see no reason whatsoever to
do a single thing beyond the dual conversion strategy we are following
now. One in hardware, one in software and the one in software done
with spur avoidance in its strategem. People continue to knock direct
conversion or near direct conversion to me regularly, only to eat their
words when the receiver is measured. Pardon me if I simply ignore
advice that does not meet with the experience I have now gained based on
the theoretical work that led to the modifications of the design which
produces the current results.
Right now, the SDR-1000, with it's AD9854 DDS is providing spectacular
receiver performance based on the "dual conversion" strategy we are
using. The lab numbers speak for themselves. I do not need to argue
about it and this is my last note on it. DDS technology is marching on
(and has) and I see no reason to tie a new generation down when a simple
disconnect could be engineered to make substitution possible.
73's
Bob
N4HY
Lyle Johnson wrote:
Isn't dithering equivalent to phase noise? Trading off one of the
DDS' greatest strengths to help overcome its greatest weakness...
Lyle KK7P
