Hi Johnny, I'm not familiar with the IC7800, but in general an image-reject mixer uses the same basic principle. It's the same as the "phasing" method of SSB generation used 50 years ago, except that they didn't use the word "quadrature" or "I/Q" in those days.
Alan N1AL On Tue, 2011-07-26 at 23:31 +0800, Johnny Siu wrote: > Hello Alan, > > I have limited knowledge of radio. > > Is that the operation theory of quadarature down-sampling something > similar to the image rejection mixer in the IC7800? > > Excuse me if I ask a stupid question. > > TNX & 73, > > > Johnny VR2XMC > > 從︰ Alan Bloom <n...@sonic.net> > 收件人︰ Gary D Krause <n7...@bresnan.net> > 副本(CC)︰ Elecraft <elecraft@mailman.qth.net> > 傳送日期︰ 2011年07月26日 (週二) 11:08 PM > 主題︰ Re: [Elecraft] KX3 and Quadarature down-sampling > > On Tue, 2011-07-26 at 08:44 -0600, Gary D Krause wrote: > > I've been wondering what Quadarature down-sampling is? This is the first > > that > > I have heard of it. > > It's like a two-channel direct-conversion receiver. The two channels > are on the same frequency but use local oscillators that are 90 degrees > out of phase. With suitable processing, the in-phase (I) and quadrature > (Q) mixer outputs give both the amplitude and phase of the signal. > Among other things, that makes it possible to suppress the unwanted > sideband of an SSB signal without a crystal filter. > > Alan N1AL > > > ______________________________________________________________ > 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 > ______________________________________________________________ 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
