Sounds like Flex may be adopting a direct sampling approach similar to
openHPSDR Mercury and Hermes. For anyone interested in details of
direct sampling design, I can highly recommend the 2008 TAPR Digital
Conference video featuring Phil, VK6APH describing the design of
Mercury. See DVD #6 at:
< http://www.arvideonews.com/dcc2008/index.html >
If this is indeed what Flex has in store, it will be interesting t
compare how they do it.
Pete, N3EVL
PS I have no financial interest in sales of this DVD.
On 5/15/2012 10:45 AM, Brian Lloyd wrote:
On Tue, May 15, 2012 at 7:07 AM, Drax Felton<draxfel...@gmail.com> wrote:
So how does a lack of base band conversion improve upon what the flex 5000
already does?
Drax, you need to understand how a direct sampling receiver works. In
essence, it uses an analog-to-digital converter connected directly to the
antenna. (In reality there is buffering, matching, and filtering to keep
unwanted signals out of the A:D but the basic concept is the same.) The
other part of the secret is called decimation, which allows you to trade
bandwidth for dynamic range. So the receiver can go from being a wide-band,
see-everything-from-1.8MHz-to-54MHz, radio, to a narrow-band radio with
world-class dynamic-range and IP3 numbers at the flip of a software
"switch". (BTW, it does still need a good front-end filter.)
So, yes, a direct-sampling radio would be a game-changer (in my
not-so-humble opinion).
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