Alan Bloom wrote:
>
> On Mon, 2008-12-01 at 06:35, ab2tc wrote:
>> Hi,
>>
>> I, too, would be very interested in seeing how "entire HF spectrum
>> digitized
>> at once" receivers would fare in the real world. I am *very* skeptical.
>> Although the Perseus (with that architecture) receiver fares relatively
>> well
>> in the recent ARRL test,
>
> It compares well for third-order intermodulation distortion, but not for
> blocking dynamic range. The A/D converter is very linear within its
> range, so you can get some fantastic TOI (third-order intercept) numbers
> if you measure with signals near the top of the ADC range. However the
> ADC full-scale signal level is less than a conventional mixer can
> handle.
>
Correct. I believe the Perseus only has a 14-bit ADC so it's more limited
in dynamic range than the 24-bit ADCs commonly used by other SDR rigs. Its
dynamic range may be OK for IMD but today's SDRs cannot approach the BDR of
rigs like the K3 until even higher resolution ADCs become available.
I believe the best BDR I've seen for any SDR is the Flex 5000, which has
just over 120 dB...the K3 is better by about 20 dB.
73, Bill W4ZV
P.S. How many hits for "1000 " or "5000 " in the contest soapbox so far?
ZERO. (Which says something about SDRs in use by real contesters).
--
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http://n2.nabble.com/K3---ADAT-ADT-200A-by-HB9CBU-tp1597981p1599961.html
Sent from the Elecraft mailing list archive at Nabble.com.
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