sixothree 11 hours ago

Do we still use piezo to power clock circuits of modern computers?

  • nakamoto_damacy 10 hours ago

    no, we use atomic clocks now... j/k

    piezoelectric refers to generation of electricity from pressure applied to the material... the inverse of that effect is what generates oscillation.. quartz has a natural resonant frequency determined by its shape, size, and the way it’s cut, and when you apply AC it oscillates at a specific frequency.. the applied electricity causes is the material to deform.. that is the basic physical effect used in oscillators

    MEMS oscillators are increasingly replacing quartz in compact, rugged, or integrated designs.

    PLL-based frequency synthesis is used to scale a low-frequency reference (e.g., 25 MHz crystal) up to CPU/GPU GHz speeds.

    • willis936 10 hours ago

      MEMS are made on a different process than other silicon devices, which slightly increases their cost. They also need to have hermetically sealed packaging, same as quartz. Together there is little fundamental savings to be had with MEMS, but they do offer a higher ceiling on performance. I don't see crystals going away anytime soon.

      Also, if you get a MEMS in a small epoxy / CSP package be weary of gases that permeate the packaging material, such as helium.

      https://hackaday.com/2018/10/31/helium-can-stop-your-iphone-...

wizardforhire 17 hours ago

Obligatory must watch old dod training film on the subject.

https://youtube.com/watch?v=ZYyAYIUvI-M&pp=ygUiUXVhcnR6IGNye...

  • mikkupikku 14 hours ago

    I wish people still talked with the accent/style used in these old videos. It's so easy to understand and listen to, compared to the typical modern American accent.

    • ahartmetz 11 hours ago

      It seems to be https://en.wikipedia.org/wiki/Good_American_Speech aka Mid-Atlantic Accent - an artificial accent - with a fairly strong natural accent of the speaker coming through.

      • kulahan 7 hours ago

        What is an artificial accent? Isn't every accent just the way people choose to speak?

        • FuriouslyAdrift 6 hours ago

          It's a way of speaking taught in broadcasting and acting schools

          • kulahan 6 hours ago

            I was under the impression that this is effectively teaching people to speak without any accent at all

            • FuriouslyAdrift 6 hours ago

              Oh no... it's an "accent". It's just a "desirable" one. Kind of like a posh accent in England.

              • kulahan 5 hours ago

                Well no, definitely not - it’s just meant to be as clear as possible. The point is to make sure as many people as possible can understand you, which is very important in informational and entertaining broadcasts.

            • mrguyorama 4 hours ago

              >effectively teaching people to speak without any accent at all

              There's no such thing as "no accent"

        • mitthrowaway2 6 hours ago

          An artificial accent is one where there are no native speakers raised with it, but rather people are professionally trained to speak with it.