Hi Walter, In response to your comments on my post, the terminology you use and that I used both appear in various texts to describe the same thing. Not surprising, we both know what one another mean. I prefer incident because quadrature is in relationship to that. An AM signal would appear on the incident stream. Quadrature then is necessary for most (all) of the other modulation schemes. In software the in-phase or incident stream appears as the real part of the complex number. That fits with the idea of incident for me. Tomato tomatoe.
Actually I meant direct conversion. I was referring broadly to SDR but thinking of the KX3 which I own and not the K4 which I am less familiar with. I'll have to look at the K4 more carefully but it sounds like its architecture is what I called Hybrid. That would make sense given its price point and less portable size along with better performance. Would you then consider the Yaesu FTDX-101D as more similar to your understanding of the K4 architecture (excepting the yaesu rather goofy interface, in my personal opinion). I expect it's not exactly the same but how would you compare them from an SDR perspective? Getting from RF to base band and back to RF is relatively straight forward. The interesting stuff IMHO is Fast Fourier, Filters and other fun software stuff. In responding to a list serve, we are writing off the cuff. If one understands the other and then has useful discussion, it's good for me. I will look over the books I have and review using whatever the more common and clear terminology is. I'm by no means an expert and I am learning myself. My primary interest is in system architectures. My interests go beyond Elecraft. I seek a taxonomy of SDR implementations which might be helpful in comparing products or understanding innovations. Thanks for the link. I was aware of that among other sources. Here is one that I have found helpful: Practical Signal Processing by Mark Owen. I am sure you know this link: https://greatscottgadgets.com/sdr/ He mentions Owen's book as well. This is also quite good with a discussion of the Tayloe mixer/detector (again two used terms). https://www.arrl.org/files/file/Technology/tis/info/pdf/020708qex013.pdf Here is a discussion of Tayloe that I think is helpful http://www.norcalqrp.org/files/Tayloe_mixer_x3a.pdf As for history, if you look at John Renshaw Carson's original paper on SSB you will see the concepts of IQ in his calculus. Here is Wikipedia. https://en.wikipedia.org/wiki/Single-sideband_modulation Fun fact, there is a picture of Einstein, Sarnoff, Steinmetz and others with someone often falsely claimed to be Tesla. It isn't. It's Carson. Geoff W1GCF ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
