Path: ...!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!eternal-september.org!.POSTED!not-for-mail From: john larkin Newsgroups: sci.electronics.design Subject: Re: BAW Date: Sat, 25 Jan 2025 09:05:42 -0800 Organization: A noiseless patient Spider Lines: 133 Message-ID: References: <7cf2pjtu3bcuc30rdpb7ls239psaso2gu8@4ax.com> <4m43pjld8pkvfdms1d37pfva2qnomblhk9@4ax.com> <24r9pjpgnk4ia3d7tkjd8v53p3idhl0oi7@4ax.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Injection-Date: Sat, 25 Jan 2025 18:05:46 +0100 (CET) Injection-Info: dont-email.me; posting-host="9cba7c597f879e65ecd208332098d274"; logging-data="3085431"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1970K9lA/Ra7RmgU/9zMUl4" User-Agent: ForteAgent/8.00.32.1272 Cancel-Lock: sha1:xHDv4ld5zV9iC+HvCWL/FPPzWUQ= Bytes: 6542 On Sat, 25 Jan 2025 13:55:05 +0000, Cursitor Doom wrote: >On Fri, 24 Jan 2025 17:46:24 -0800, john larkin wrote: > >>On Sat, 25 Jan 2025 00:41:39 +0000, Cursitor Doom >>wrote: >> >>>On Wed, 22 Jan 2025 17:09:29 -0800, john larkin >>>wrote: >>> >>>>On Thu, 23 Jan 2025 00:55:25 +0000, Cursitor Doom >>>>wrote: >>>> >>>>>On Wed, 22 Jan 2025 10:55:39 -0800, john larkin >>>>>wrote: >>>>> >>>>>>On Wed, 22 Jan 2025 18:07:06 +0000, Cursitor Doom >>>>>>wrote: >>>>>> >>>>>>>On Mon, 20 Jan 2025 16:26:10 -0800, john larkin wrote: >>>>>>> >>>>>>>>On Mon, 20 Jan 2025 19:52:03 -0000 (UTC), Phil Hobbs >>>>>>>> wrote: >>>>>>>> >>>>>>>>>john larkin wrote: >>>>>>>>>> https://www.ti.com/product/CDC6C >>>>>>>>>> >>>>>>>>>> These are like 35 cents at 1K. >>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>>>Of course a crystal oscillator is a BAW device too. ;) >>>>>>>>> >>>>>>>>>Cheers >>>>>>>>> >>>>>>>>>Phil Hobbs >>>>>>>> >>>>>>>>Don't get technical with me! >>>>>>>> >>>>>>>>I wonder if it's all silicon, a sort of bulk MEMS thing. The price is >>>>>>>>absurd. I guess every one has to be trimmed to frequency. >>>>>>> >>>>>>>Phil's pretty good in that regard. There are some people who see >>>>>>>everything in terms of equations and use higher mathematics to explain >>>>>>>their function. A xtal oscillator would provide a very simple example >>>>>>>for such persons to exhibit this (most unfortunate) character trait. >>>>>> >>>>>>Phil is one of those people who can see equations in motion. I can't. >>>>>>I operate on instinct and simulation. >>>>>> >>>>>>We have brainstormed on some pretty important projects and generated >>>>>>some ideas that influence most everyone here. The skills are >>>>>>complementary. >>>>>> >>>>>>His book is good to have if you design electro-optics or low-level >>>>>>analog stuff. >>>>>> >>>>>>https://www.amazon.com/Building-Electro-Optical-Systems-Making-Applied/dp/1119438977/ref=sr_1_fkmr0_1?crid=3M9PG1T68443R&dib=eyJ2IjoiMSJ9.xIlGO_AWviZZRYMlHFKJuNzKnLc8MDBpUjgE7RsYsDk.WiFCuc8GjBlGtPimMCFx0kOu5NieBv0TzXDNCokyLQM&dib_tag=se&keywords=phil+hobbs+optics&qid=1737571796&s=books&sprefix=phil+hobbs+optics%2Cstripbooks%2C138&sr=1-1-fkmr0 >>>>>> >>>>>>Be cautioned that there are equations. >>>>> >>>>>Equations are fine (unavoidable anyway) in this science. But it's not >>>>>helpful in the first instance to gain an intuitive idea of how >>>>>something works - unless you're one of the people I mentioned above. >>>>>This is my main issue with Tom Lee's otherwise superb book, 'Planar >>>>>Microwave Engineering' where he typically launches into higher >>>>>mathematics almost from the get-go. >>>> >>>>I have that book. It's mostly useless. One equation will be a full >>>>page of fine print, and then the next page turns out to be one term of >>>>that equation. >>> >>> >>>Indeed. Not only that, but the mathematics is unfamiliar. I know most >>>of the equations for transmission line theory by sight, but the ones >>>Tom cites are completely different and tend to use a lot of Greek >>>letters which relate to physical constants I've never even heard of. >>>On the other hand, where he doesn't use unfamiliar mathematics, >>>there's a *lot* in there I haven't seen any any other RF books which I >>>find really interesting. >> >>It's easier to design with a geometry for which there are good >>calculator programs. >> >>We have used ATLC to do e/m simulations of transmission line cases. >> >>https://www.dropbox.com/scl/fi/6kdejmbybk4u5mq1xjait/Edge_alone_4.jpg?rlkey=volom4afazo44o6cpedgl89ge&raw=1 >> >>https://www.dropbox.com/scl/fi/82ysq5m13br8ahubdi4z7/Rob1.jpg?rlkey=4bnm3uu5otfolka9gqsov5tel&raw=1 >> >>https://www.dropbox.com/scl/fi/ogfqs1m93mf1uw80hwkpi/Rob_51_ohms.jpg?rlkey=u4q3fumbzwmpojck5ih88c45q&raw=1 >> >>That one butchers a multilayer PCB stack to get a good match with a >>cheap edge-launch SMA connector. >> >>https://www.dropbox.com/scl/fi/n7hlatrxdoiywfkvebqj9/DSC01527.JPG?rlkey=hycib2nrk4zv662mu5vndy23g&raw=1 >> > >I had to google ATLC simulator as I've not heard of it before. Anyway, >these plots are all very interesting, but you have no way of verifying >their accuracy AFAICS. >You mentioned a while ago you had a good source for cheap but >reasonable quality edge connectors (Aliexpress?) Can you post a link >to them please? ATLC2 is a bit easier to drive. The way to verify a sim is to make a board and TDR it. They are usually close. The one in the pic above is from Shining Star. SHINING STAR 19521000 We use SHINING STAR 24521116 too, a bit longer part. Both about $1.90. I've bought a bunch of similar ones from Amazon and they have been great. But it's our general policy to not use Amazon parts in production. Here's a 4-layer proto board that let us TDR the connectors and the relay. https://www.dropbox.com/scl/fi/bvcnqnvb4euc7pqw7wzab/DSC06884.JPG?rlkey=q1op81z1bumkfxoq8d5mtzi91&raw=1