Re:RF Breadboarding System
by teleforce on Saturday April 22, 2023 @07:09AM
(#35665323)
RF electronics, systems and control are normally considered as black arts in the electronics community due to the "distributed" nature of RF signal waves propagation. Most of the RF literatures even by the veteran experts are still working in the obsolete old school framework without regards for the other improvements in the field for example software-defined radio (SDR). For those who want to know modern approach to RF systems design please check these two books by Earl McCune and Huseyin Arslan [1][2].
However something very important is missing from many of these RF books including the books mentioned above. The most important thing is how to reliably and accurately detect, measure and control the impedance of RF signals. This topic is so pertinent that the terminology of "impedance mismatched" is even widely used outside of the RF domains or circles. The mechanism for detecting, measuring and controlling impedance mismatched is relatively unknown outside RF community that are called load-pull and source-pull. Coincidentally these happened to be part of my research study topics about 15 years back and it's a kind of solved problem now even for RF wideband signals that are common in modern RF system set up. Spoiler alert, to do it properly it cannot be done in analog domain but need to done in digital domain. Looking back on why the solution is not popular although it is being openly published is quite a mystery to me personally. Perhaps this what Dijkstra lamenting why his solutions to OS problems were oblivious to most OS implementors was perhaps because he is not from MIT.
The solution is not without its limitation because real-world RF signals have baseband, fundamental and several harmonics and the solution does cover the baseband due to the limitation of direct conversion transceiver being used. But now since companies like AD and TI have managed to manufactured fully digital high frequency ADC/DAC transceiver architecture that the limitation kind of disappeared for good.
However something very important is missing from many of these RF books including the books mentioned above. The most important thing is how to reliably and accurately detect, measure and control the impedance of RF signals. This topic is so pertinent that the terminology of "impedance mismatched" is even widely used outside of the RF domains or circles. The mechanism for detecting, measuring and controlling impedance mismatched is relatively unknown outside RF community that are called load-pull and source-pull. Coincidentally these happened to be part of my research study topics about 15 years back and it's a kind of solved problem now even for RF wideband signals that are common in modern RF system set up. Spoiler alert, to do it properly it cannot be done in analog domain but need to done in digital domain. Looking back on why the solution is not popular although it is being openly published is quite a mystery to me personally. Perhaps this what Dijkstra lamenting why his solutions to OS problems were oblivious to most OS implementors was perhaps because he is not from MIT.
The solution is not without its limitation because real-world RF signals have baseband, fundamental and several harmonics and the solution does cover the baseband due to the limitation of direct conversion transceiver being used. But now since companies like AD and TI have managed to manufactured fully digital high frequency ADC/DAC transceiver architecture that the limitation kind of disappeared for good.
[1] Practical Digital Wireless Signal:
https://www.cambridge.org/core/books/practical-digital-wirel...
[2] Wireless Communication Signals: A Laboratory based Approach:
https://www.wiley.com/en-ie/Wireless+Communication+Signals:+...