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Fw: [FARS-Announce] FARS March Meeting - Tonight!
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Fact Checking: The active cascode amplifier was invented in 1979 and included in Analysis and Design of Analog Integrated Circuits, first edition 2001. They are a refinement of the cascode amplifier which goes back to vacuum tubes. I back in the day, I used discrete transistors for amps into 10's of MHz. The abstract to Ed's talk said they were what made the NanoVNA and TinySA possible. These devices use direct conversion. No amplifier on the front end. Yes, they have mixers and switches for the input circuits. The enabling hardware for these amazing devices is mostly the digital chips and a display that can all be powered by a battery.
That said, these hand held devices are can be really handy.
----- Forwarded Message ----- From: Steve Stearns via FARS-Announce <fars-announce@...> To: 'FARS Announce' <fars-announce@...> Sent: Friday, March 28, 2025 at 11:08:13 AM PDT Subject: [FARS-Announce] FARS March Meeting - Tonight! Foothills Amateur Radio Society Membership Meeting on Friday March 28 ... Presentation:? Broadband (4 GHz) Precision Amplifiers ? Summary:? We are now all familiar with the NanoVNA and the Tiny SA.? There are also numerous digital scopes now that are very affordable.? An example is the DSO03D12 -? a dual trace color portable oscilloscope with probes that easily measures in real time up to 150 MHz.?? This instrument also has built in DVM and signal generator – all for less than $150.? These instruments would have cost in the thousands of dollars 10 years ago. ?Only the most serious hams own expensive HP or Tektronix equipment?? So why are they now all so affordable??? The simple answer is an innovative operational amplifier (“op amp”) design.? For the last 50 years, op amp design followed a tried-and-true formula that did not change.? Dave Fullagar designed the uA 741 in 1968. ?It had unity gain bandwidth of 1.5 MHz.? True, small incremental improvements happened over the years, such as current mode feedback.?? However, these were evolutionary, not revolutionary.? Steady improvement in semiconductor processing gave incremental gains in frequency response (10’s of MHz at most). ?However, in the early 2000’s a new amplifier topology was invented that allowed controlled high precision feedback gains in the 4-6 GHz range.? This configuration is only now finding its way into amplifier text books.? Ed will explain this new circuit configuration and how it works. ? About the Speaker:? Ed Fong, WB6IQN, teaches RF Wireless Communications and I/O Design Fundamentals for UC Santa Cruz in Silicon Valley. He taught RF Wireless at UC Berkeley from 1998 to 2011.? Ed is the owner of Ed’s Antennas . ?Ed’s DBJ-1, DBJ-2, and TBJ-1, dual- and tri-band antennas are popular with hams, commercial and government users, and were featured in magazine articles in QST (February 2003, March 2007, and March 2017) and CQ (Summer 2012), and reprinted in three ARRL books:? VHF/UHF Antenna Classics (2003), Antenna Compendium Volume 8 (2010), and Portable Antenna Classics (2015).? Ed’s past presentations to FARS include the uSDX+ portable HF transceiver (November 2023), phase-locked loops (August 2023), single-sideband modulation (January 2023), ground-independent vertical antennas (August 2019), and DMR radio (April 2018). |