> I'd call the K3 a hybrid SDR and the KX3 a true SDR?
No - both are hybrid SDRs if that's the term you want to apply. The K3 is a traditional IF based superhetrodyne/SDR where the KX3 is a "zero IF" or direct conversion SDR. The K3 uses two stages of IF - 8.125 MHz and 15 KHz - with SDR modulation and demodulation at 15 KHz. The KX3 is a direct conversion (RF to DC) front end with SDR based I/Q modulation and demodulation. Neither is a "pure" SDR if your definition of a "true" SDR is "on frequency" analog to digital and digital to analog conversion. 73, ... Joe, W4TV On 12/23/2012 1:34 PM, John Lawrence wrote:
Don As I'd expect, you did a beautiful job summarizing the difference between the K3 and KX3 design architecture. I'd call the K3 a hybrid SDR and the KX3 a true SDR? What's interesting to me comes from looking at the leap forward in component technology to make direct SDR from RF possible. This is the evolution in the chip level devices it takes to gain this single step conversion to baseband. Faster and more agile DSP, A/D and D/A etc ICs are at the heart of the step forward between the K3 and KX3. The companies producing these chips were at my fingertips back in the days 10 to 20 years ago. Then they were only able to make it to lower frequency IF stages with costly designs only found in the top high tech applications such as those found in government surveillance. Back then Burr Brown, Analog Devices, Texas Instruments, Motorola, Lucent/Bell Labs were working hard with competitive designs. Semiconductor foundry geometries were heading for half micron on 4" or 6" silicon back then. The software development tools allowing greater coding efficiencies is another area that has played a major roll to bring us to this point. And, his was all done within our free enterprise environment by private/public capitalized US businesses. Happy Holidays John, W1QS Waldoboro, Maine ______________________________________________________________ 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
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