Re: Yttrium iron garnet

On Fri, 31 May 2024 13:29:02 +0200, Jeroen Belleman
<jeroen@nospam.please> wrote:

On 5/31/24 12:40, john larkin wrote:

On Fri, 31 May 2024 00:04:47 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
 

john larkin <jl@650pot.com> wrote:

On Thu, 30 May 2024 21:46:20 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

john larkin <jl@650pot.com> wrote:

On Thu, 30 May 2024 11:03:19 GMT, Glen Walpert <nospam@null.void>
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
<cd999666@notformail.com> 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guessing they've been completely superseded by now to get to ever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:
>
<https://www.microwavejournal.com/articles/37980-reinventing-yig-
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.

>
Coaxial ceramic resonators have Qs in the thousands, and low tempcos.
>
>

If you can find one at the exact frequency you need.  YIGs have a huge
tuning range.
>
IIRC you also said that they’re piezoelectric.

 
The CCRs are high-K, usually shorted, transmission lines, not
piezoelectric. Prop delay is a tiny fraction of c. You can TDR them as
such. Z is usually in the 10 ohm ballpark.
 

>
I’m not saying that YIG is the answer to everything, but for some things
it’s amazing and (AFAIK) unique.

 
No argument, but they will always be big and expensive slow-tuning
power hogs, which is fine in a spectrum analyzer.
 
RF synthesizer chips are pretty amazing these days too. They make a
pretty good first LO too, but they are small and cheap.
 

>
Sure improves spectrum analyzers!

 
I wonder if the latest SAs use YIGs.
 
 

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Cheers
>
Phil Hobbs

>
I gather many spectrum analyzers these days mix successive
slices of the spectrum down to where an ADC can acquire the
whole slice, and the remaining processing is all software FTs.
>
No need for YIG oscillators, and the LO synthesizer needs
only coarse steps.
>
Jeroen Belleman

Yes, digital IF.

The price of a several-GHZ sa has dropped by over 10:1 in the last 20
years, mostly from using a lot of digital stuff.

You can get an impressive 8 GHz RF synth chip for about $5 now.