Isamu
3 hours ago
>Broadcom will produce advanced radio frequency components — including FBAR filters
Thin-film bulk acoustic resonator
https://en.wikipedia.org/wiki/Thin-film_bulk_acoustic_resona...
>Trends to utilize RF spectrum more efficiently with higher frequencies than roughly 1.5–2.5 GHz and in some cases also simultaneously with increasing RF output power have supported FBAR technology to become one of the key enabling technologies in telecommunication realisations. FBAR technology complements and in some cases competes with surface acoustic wave (SAW) technology and FBAR resonators can replace crystals in crystal oscillators and crystal filters at frequencies more than 100 MHz.
MrBuddyCasino
3 hours ago
Fascinating. I suppose they can be smaller than quartz crystals?
ahartmetz
an hour ago
If you find that fascinating already... did you know that all cellphones use mechanical filters in the GHz range? They combine very good performance with very low energy consumption.
https://en.wikipedia.org/wiki/Surface_acoustic_wave
https://de.wikipedia.org/wiki/Akustische-Oberfl%C3%A4chenwel... (pictures)
MrBuddyCasino
an hour ago
Honestly, the "HF physics is black magic" trope has made me numb to the phantastical contraptions. I appreciate when they look cool, like esoteric orgon wave radiators.
MobiusHorizons
3 minutes ago
Small note of clarification. HF in a radio frequency (RF) context actually refers to what we would now consider fairly low frequencies between 3 and 30mhz where wavelengths are in the tens of meters. The black magic is mostly in UHF AND microwave regions where wavelengths start to measure closer to the size of circuit elements.
Although I have also heard it said “RF physics is black magic” to cover all the bases
ahartmetz
36 minutes ago
AFAIK, the black magic factor is much higher for HF electronics than for HF mechanics. It's at least partially because you can build more complex systems with HF electronics. The other difference is that high frequency EM oscillations easily radiate energy in the form of photons, while high energy mechanical oscillations radiate nothing for practical purposes (at least in vacuum), gravity waves if you're being pedantic.
drum55
3 hours ago
Very little uses crystal oscillators, they’re gigantic compared with electronics today and have very wonky performance over temperature and shock.
i_am_a_peasant
an hour ago
even txco's?
MrBuddyCasino
39 minutes ago
You probably know this, they don't have wonky performance but are even bigger. An oven around a crystal.