Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: Cursitor Doom Newsgroups: sci.electronics.design Subject: Re: OT: Covid's True Origins Date: Wed, 23 Apr 2025 11:56:39 +0100 Organization: A noiseless patient Spider Lines: 77 Message-ID: References: <6803c489$6$2787$882e4bbb@reader.netnews.com> <95i70k5mcgcs15fe8c5cds703mrchbujc5@4ax.com> <68057a5c$0$4264$882e4bbb@reader.netnews.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Injection-Date: Wed, 23 Apr 2025 12:56:43 +0200 (CEST) Injection-Info: dont-email.me; posting-host="5f3eed54c7377c87089c1de0d9fa459a"; logging-data="3107259"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/WHDE6pXfLhmKUkCOcKcFirf9QfehkWbA=" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:urSUOsol3/dOC/HLX7OnkTN1m6A= Bytes: 4645 On Tue, 22 Apr 2025 16:29:22 -0700, john larkin wrote: >On Tue, 22 Apr 2025 15:15:01 -0700, john larkin >wrote: > >>On Tue, 22 Apr 2025 22:02:32 +0100, Cursitor Doom >>wrote: >> >>>On Mon, 21 Apr 2025 15:02:17 -0700, john larkin >>>wrote: >>> >>>>On Mon, 21 Apr 2025 22:23:03 +0100, Cursitor Doom >>>>wrote: >>>> >>>>>On Mon, 21 Apr 2025 08:26:40 -0700, john larkin >>>>>wrote: >>>>> >>>>>[...] >>>>>>Sine waves are boring. >>>>> >>>>>Well, square waves give rise to lots of harmonics which can be useful. >>>>>But what about triangles and sawtooths. Any interesting properies >>>>>hidden away in those? >>>> >>>>Periodic waveforms are all boring. They just do the same thing, over >>>>and over. >>>> >>>>A complex pulse can do interesting things. Spin an airplane. Fuse >>>>deuterium-tritium. Trigger a megaton boom. >>>> >>>>I wish the world would move on from the slide rule and graph paper >>>>days, narrowband s-parameters and Smith charts and load pulls. We have >>>>computers now. >>> >>>It's dumb *not* to use computers for the complicated and trap-ridden >>>calculations relating to impedance transformations, filters and >>>transmission lines. *However* if someone using computers for this >>>purpose hasn't been schooled in the derivation of the calculations by >>>learning how the Smith Chart was developed and how it got that scary, >>>warped shape, then they're going to be too far abstracted from the >>>underlying physics to be able to understand fully what's going on >>>under the hood. And they'll be that much poorer for it. Like people >>>who use rules-based calculus to solve problems because they have >>>little understanding of the nuts and bolts of derivatives and >>>integrals. Ask them to solve a new problem and they're lost! >> >>No, don't just automate the antique concepts. We need Spice For RF, >>genuine wideband time-domain analysis. Anything interesting is >>nonlinear anyhow. >> >>https://www.ineltek.com/en/qorvo-qspice-neues-simulationstool-fuer-rf-und-leistungselektronik-schaltungsdesigns/ > >I develop my own Spice models for MMICs and phemts and distributed >amplifiers and other RF parts. That usually involves measurements, >because most RF parts don't even specify DC things. Some data sheets >say "adjust the bias until it works" or "ac couple the input and >output." Yes, they're generally poor on detail for sure. >I drive electro-optical modulators with narrow pulses. The RF part >data sheets assume a continous, symmetrical sine wave. I can get twice >the swing for pulses if I bias a distributed amp way off-center. You should get yourself a curve-tracer - or design one (and share that with me so I can build one).:) >RF parts seem to specify their abs max voltage assuming that a sine >wave might swing from ground to 2xVcc, but the data sheet specifies >abs max Vcc. So one has to cheat. > >Testing a $300 distributed amplifier chip for its genuine abs max >output voltage limit is emotionally tricky. I would imagine so, yes. However, at least today you can launch a crowd-funding appeal to share the burden. ;-)