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. > the testing completely ignores what happens when > there are not *two* but thousands of strong signals in the passband. Exactly. > With > this new architecture, it's imperative that ARRL and other labs find other > ways of evaluating real world performance as a simple two-tone test becomes > completely irrelevant. > > Toby Deinhardt wrote: > > > > Hi, > > > > has anybody done a serious test of the ADT-200A transceiver yet? > > > > <http://www.adat.ch/index_e.html> > > <http://www.adat.ch/pub/Presentation_Hamfest_22-09-07.pdf> > > <http://www.adat.ch/pub/ADT-200A_Messresultate_V10.pdf> > > > > It would be rather interesting to see how the concept used by the K3 (24 > > bit digitalization after IF) compares in the real world to the early 14 > > bit digitalization as used by the ADT-200A (and afaik by the Perseus RX > > from Microtelecom), especially with the chips available currently. > > <snip> > > > > > > > ----- > AB2TC - Knut Al N1AL _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
