Path: ...!news.nobody.at!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Phil Hobbs Newsgroups: sci.electronics.design Subject: Re: Yttrium iron garnet Date: Thu, 30 May 2024 21:46:20 -0000 (UTC) Organization: A noiseless patient Spider Lines: 66 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Thu, 30 May 2024 23:46:21 +0200 (CEST) Injection-Info: dont-email.me; posting-host="911b746829b58010afd4e308b69077fe"; logging-data="1969866"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+5i32xxzPqGbpuft+U1wub" User-Agent: NewsTap/5.5 (iPhone/iPod Touch) Cancel-Lock: sha1:D3Gl79LYqKWaT05nR09mX+0CYLI= sha1:Nz0MVJ3f36zz77qMXbXwEClzldA= Bytes: 3785 john larkin wrote: > On Thu, 30 May 2024 11:03:19 GMT, Glen Walpert > wrote: > >> On Thu, 30 May 2024 09:14:58 -0000 (UTC), Cursitor Doom wrote: >> >>> On Thu, 30 May 2024 15:45:21 +1000, Bill Sloman wrote: >>> >>>> On 30/05/2024 3:37 am, john larkin wrote: >>>>> On Wed, 29 May 2024 17:12:21 -0000 (UTC), Cursitor Doom >>>>> wrote: >>>>> >>>>>> On Wed, 29 May 2024 13:52:34 +1000, Bill Sloman wrote: >>>>>> >>>>>>> Yttrium iron garnet tuned oscillators were around back then, but >>>>>>> their 2GHz to 8GHz range was too high for me to count with the >>>>>>> integrated circuits around then - we had to go the Gigabit Logic's >>>>>>> GaAs parts to get to 800MHz, and that became the unique selling >>>>>>> point of the system. >>>>>> >>>>>> YIG oscillators were quite the thing back in the day, but I'm >>>>>> guessing they've been completely superseded by now to get to ever >>>>>> higher frequencies. Seems we've gone from - >>>> >>>> This misses Jan Panteltje's thread "Small magnetic tunable filter for >>>> 6G and beyond" which is about Yig being used today. >>> >>> That article makes it seem like YIG is some revolutionary, new, emerging >>> technology! >> >> Use of YIG filters as a replacement for varactor tuning could turn out to >> be significant. 2022 Microwave Journal article: >> >> > technology-for-microwave-filter-applications> > > The VIDA oscillators still look like giant expensive power hogs. They > don't specify modulation bandwidth on the data sheets that I see, but > it must be terrible. > > One can't modulate a hundreds-of-mA electromagnet very fast. > > An LC osc with a varicap is a more sensible VCO. Narrowband, one can > varicap a coaxial ceramic resonator, or a PCB ring oscillator, or > something. Cheap and fast. And far, far noisier than the best YIGs. > > Of course, it's inherently difficult to modulate a high-Q resonator > fast, even without an electromagnet in the way. It isn’t, actually, at least over a restricted range. If the resonator obeys a differential equation, you can modulate its resonance much faster than f_0/Q by changing L or C. Resonators with significant time delay, such as a long piece of coax, aren’t as friendly that way. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics