Let's see: 122 to 140dB: only 15% increase! a walk in the park... ; - )
David G3UNA ---- Geoffrey Mackenzie-Kennedy <gm4...@btinternet.com> wrote: > Larry N8LP wrote on 24 Februay 2009, at 02:40. > > > I think the days of receivers with xtal filters are numbered. High speed > > ADCs capable of 140dB dynamic range without xtal filtering are on the > > horizon. A 20-bit ADC with enough processing gain would do it. > > ------------------------------ > Larry, > > You could be right, given an adequate amount of R&D funding and time. > > When the performance of a state of the art HF receiver using xtal filters > will be surpassed by one digitizing at signal frequency is an open question > I think.. The performance standard in terms of Spurious Free 3rd > Order dynamic range vs. time set in recent years by real HF superhet > receivers using xtal filters, as I know it to be, is: > > Year 3rd Order SFDR 3rd Order SFDR Filter Noise > @ 2 kHz In Passband BW Figure > > 1993 110 db 95 db 400 Hz 8 db > > 2007 122 db approx 115 db 500 Hz 7 db > > > So don't put the old horse out to pasture just yet :-) > > Sorry to have digressed from the subject matter. > > 73, > Geoff > GM4ESD > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
