[HN Gopher] World's smallest, best acoustic amplifier emerges fr...
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World's smallest, best acoustic amplifier emerges from 50-year-old
hypothesis
Author : skunkworker
Score : 217 points
Date : 2021-06-27 05:17 UTC (17 hours ago)
(HTM) web link (www.sandia.gov)
(TXT) w3m dump (www.sandia.gov)
| simonjgreen wrote:
| This article taught be a new term.
| https://en.m.wikipedia.org/wiki/Phonon
| MaxBarraclough wrote:
| Non-mobile link: https://en.wikipedia.org/wiki/Phonon
| chrismorgan wrote:
| Digression: why do sites like Wikipedia and Twitter use
| different URLs for their mobile, given that in the end it's
| essentially the same stuff being served?
| 41b696ef1113 wrote:
| For Wikipedia, I imagine they have interests in making the
| content most accessible on the maximum number of devices.
| Which means pages crafted to be lightweight and minimal
| Javascript. Yes, you could do that all in one page, at the
| altar of developer velocity, but I think the strict
| isolation is user forward.
|
| A quick test from Firefox dev tools for initial page load:
| - https://en.m.wikipedia.org/wiki/Phonon 1.04MB, Finish 619
| ms - https://en.wikipedia.org/wiki/Phonon 1.94MB, Finish
| 1500 ms
| rozab wrote:
| Wow. I guess today I'll be writing a stylesheet to un-
| mobile-ify m.wikipedia.org
| j-james wrote:
| I use a short userscript:
|
| // @include *://*.m.wikipedia.org/*
|
| window.location.replace("https://en.wikipedia.org" +
| window.location.pathname);
| stan_rogers wrote:
| I believe the object was not so much to force mobile
| links/URLs to desktop URLs, but to style the lighter
| mobile page for the desktop.
| wiml wrote:
| IIRC it dates to before we had things like media-query in
| CSS or other good ways to adapt the page load to the
| device.
| wpietri wrote:
| Wikipedia launched that in July 2013 in response to rising
| web traffic and the existing site not working well on
| mobile browsers. That was preceded by Wapedia, an
| independent site that started in 2004 to provide a
| reformatting proxy for mobile use:
| https://en.wikipedia.org/wiki/Wapedia
|
| The basic answer is that early on the tooling wasn't there
| to support very difference devices from the same HTML. You
| could try tricks to detect mobile devices and serve
| different content. But it was much easier just to let
| people decide which they wanted.
|
| I haven't kept up, but I know the tooling keeps improving,
| so I expect that few people today are creating mobile-
| specific URLs, and that the existing ones will go away in
| the long run.
| MatmaRex wrote:
| Wikipedia's mobile site was originally running completely
| separate software (https://www.mediawiki.org/wiki/Wikimedia
| _Mobile_engineering/...).
|
| My guess is that it was easier to set up that way at the
| time, and then the configuration was kept when a mobile
| version was integrated into MediaWiki itself.
|
| There are plans to merge the domains
| (https://phabricator.wikimedia.org/T214998), although they
| are vague and stalled.
| bawolff wrote:
| I'd guess its essier to manage caching.
| mikewarot wrote:
| Surface Acoustic Wave filters are used in RF signal processing.
| They work by converting an electrical signal to a sound wave on
| the surface of a piezoelectric material, then using mechanical
| resonance effects to filter the signal to a very narrow band
| before converting it back to an electrical signal.
|
| In this setup, they have figured out how to amplify the sound
| waves without having to convert them back to electrical signals
| first. The first prototype got hot, so they could only run it in
| pulses... the second device worked continuously, and delivered
| about a modest amount of power.
|
| Eventually this technology will work its way down into all of our
| communications gear, making it even smaller, and more efficient.
| dr_dshiv wrote:
| That's helpful and makes sense for filtering. But do you have a
| sense for how their setup amplifies?
| mikewarot wrote:
| "The gain mechanism, which is analogous to an electromagnetic
| traveling-wave tube amplifer32, depends on the average
| interaction of the charge carriers with the piezoelectric
| electric field. This interaction controls the energy transfer
| from or to the acoustic wave, resulting in acoustic wave
| attenuation or amplification, respectively."
|
| Source: https://www.nature.com/articles/s41467-021-22935-1
|
| I was pleasantly surprised that it wasn't paywalled.
| jlnthws wrote:
| Their device is tiny. I don't understand how it works with low
| frequency / large wavelength sound wave. Do you?
| Zenst wrote:
| Your instinct is spot on - it does not, and just does high
| frequencies in the RF range using acoustic resonance to
| amplify instead of using electrical amplification.
| https://en.wikipedia.org/wiki/Acoustic_resonance
|
| One big aspect of this is that is from what can tell, has
| lower noise and with that a pre-amp/amp that has less noise
| in the RF domain is epic, it will allow lower power to be
| used for transmit and also offer longer range at the same
| power used today. But an amplification that has less noise
| than existing electrical only options has so many uses that
| for discovery - I'd rank this up there with graphite.
| jacquesm wrote:
| It doesn't work with low frequencies, it works with very high
| frequencies but in the acoustic domain. You're looking at
| wavelengths on the order of micrometers.
| Swenrekcah wrote:
| From what they said, an incoming RF signal is converted to
| acoustic signal. That acoustic signal is probably not in the
| human audible range. It's that signal which is filtered and
| then amplified with this new device, IIUC.
| imhoguy wrote:
| I hope won't produce some nasty coil whine.
| jacquesm wrote:
| It is thousands of times higher than the highest
| frequency that you can hear. That doesn't rule out
| interference with another frequency leading to a
| difference that is in the audible range but all things
| considered this should not happen. Also, there are no
| coils involved, it's piezo-electric.
| mikewarot wrote:
| I should have clarified "acoustic" just means a vibration,
| like sound, but in this case 274 megahertz, about 14,000
| times higher pitch than human hearing... twice FM radio
| transmissions.
|
| It eventually should result in devices that work past WiFi
| frequencies.
| amelius wrote:
| How sensitive is this to other nearby amplifiers? Would two such
| amplifiers on the same chip interfere?
| imoverclocked wrote:
| Someone in the know: Is this related to sonoluminescence at all?
| mikewarot wrote:
| no, it is not.
| amelius wrote:
| Is it related to phonons then?
|
| https://en.m.wikipedia.org/wiki/Phonon
|
| > Phonons can be thought of as quantized sound waves, similar
| to photons as quantized light waves.
| goldenkey wrote:
| This technology is entirely analog. It has nothing to do
| with quanta. It simply converts electromagnetic signals of
| a certain band, into electricity, through an acoustic
| coupling, and amplifies the signal too, in an all-in-one
| manner.
| amelius wrote:
| But the quanta can generate shot-noise, just like the
| quantized electrons can in an electronic design?
| ajot wrote:
| Is there any other part in a cellphone that requires 36 V to
| operate? It seems quite high for being stuffed into a portable
| electronics device.
| wtallis wrote:
| Flash memory requires relatively high voltage for block erase
| operations, but this is at least twice the voltage that flash
| uses. It's likely to adopt the same strategy of including
| charge pumps on board to generate the required high voltage
| from one of the lower voltages available from the system.
| kube-system wrote:
| I'm sure some parts of power conversion circuits might
| momentarily reach some voltages like that, particularly when
| you've got inductors behind switching circuits. The wiki page
| for Qi says that transmitters circuits can reach 50v, and I
| believe a few phones can serve as Qi chargers.
| dasl wrote:
| Instead of having RF interference, if we have acoustic
| transmitters, would you have trouble getting a signal at a loud
| concert for instance (acoustic interference)?
| ComputerGuru wrote:
| These are operating on EM/sound at frequencies magnitudes
| higher than anything in the audible range; there's basically no
| chance anything you can hear (no matter how loud) could
| interfere with this.
| derefr wrote:
| But are there things that produce "loud" acoustic waves at
| these ultrasonic frequencies out in the natural or manmade
| world, that we mostly just ignore because we can't sense
| them? (in about the same way that we ignore e.g. the massive
| amount of radio interference that switching power supplies
| create, because we don't use those bands for anything)
| peter_d_sherman wrote:
| >"While most radio components, including amplifiers, are
| electronic,
|
| _they can potentially be made smaller and better as acoustic
| devices. This means they would use sound waves instead of
| electrons to process radio signals._
|
| "Acoustic wave devices are inherently compact because the
| wavelengths of sound at these frequencies are so small -- smaller
| than the diameter of human hair," Sandia scientist Lisa Hackett
| said. But until now, using sound waves has been impossible for
| many of these components."
|
| [...]
|
| >"Previous researchers hit a dead end trying to enhance acoustic
| devices, which are not capable of amplification or circulation on
| their own, by using layers of semiconductor materials. For their
| concept to work well, the added material must be very thin and
| very high quality, but scientists only had techniques to make one
| or the other.
|
| Decades later, Sandia developed techniques to do both in order to
| improve photovoltaic cells by adding a series of thin layers of
| semiconducting materials."
|
| [...]
|
| >"Fusing an ultrathin semiconducting layer onto a dissimilar
| acoustic device took an intricate process of growing crystals on
| top of other crystals, bonding them to yet other crystals and
| then chemically removing 99.99% of the materials to produce a
| perfectly smooth contact surface. Nanofabrication methods like
| this are collectively called
|
| _heterogeneous integration_... "
|
| PDS: Let's revisit this quote: _" This means they would use sound
| waves instead of electrons to process radio signals."_
|
| So, I'm going to go for "full crackpot" here...
|
| How do we know that electrons aren't sound waves -- and/or radio-
| wave-like -- in nature?
|
| ?
|
| If <thing A> in the universe can be converted into <thing B> via
| a transducer, then that shows us that <thing A> and <thing B>
| share a relationship which might not be completely understood
| according to the scientific reasoning of the day...
|
| Compare to the concept of "identities" in Mathematics.
|
| Once you have a mathematical identity for some term in a math
| equation, then you can reason about that equation in different
| ways that you couldn't before -- with the guarantee that because
| the mathematical identity has previously been proven, the
| reasoning about the equation, substituting a term with one of its
| proven identites -- will be correct...
|
| In other words, can we reason about electrons as sound waves,
| and/or as radio waves, and will the results of that reasoning be
| correct?
|
| ?
| wizzwizz4 wrote:
| > _In other words, can we reason about electrons as sound
| waves, and /or as radio waves, and will the results of that
| reasoning be correct?_
|
| The _movement_ of electrons is a bit like the _movement_ of
| air; that 's why they share the relationships. This doesn't
| tell you much about the nature of air molecules or electrons.
| (It's actually using a solid, not air, as the acoustic medium,
| but my point still stands.)
|
| It works the other way around, though:
| https://en.wikipedia.org/wiki/Phonon
| ridruejo wrote:
| "The Sandia scientist leading that effort happened to share an
| office with Matt." There are some serenpidity advantages to being
| colocated :)
| vinay_ys wrote:
| I had a similar reaction to that sentence. A very good reminder
| that WFH can be disadvantageous to this type of creative cross-
| polination.
| birdyrooster wrote:
| Which is why we should go back to satellite offices and rub
| shoulders explicitly with people that aren't on our team.
| diydsp wrote:
| and/or co-working spaces where we can cross-pollinate ideas
| with people on the fringes of our own experience... or even
| people with various socioeconomic backgrounds and
| demographics... there must be a sweet spot between "old
| school IBM suits" and "coding from soup kitchens"
| KMag wrote:
| We just returned to office recently, and a team I hadn't
| worked with in about 6 years just moved to the next row over.
| Their second day in their new location, and I overheard them
| talking about a rare segfault (thousands of processes, hits
| them about once a month) that had been perplexing them for
| months. I had a bit of intuition and a good guess, and in a
| few hours had an ugly proof-of-concept fix they were testing.
| It took another week for a colleague to clean up,
| productionize, and properly test a robust solution.
|
| It got me thinking about ways to artificially introduce
| opportunities for such serendipity in a remote work
| environment, but I haven't come up with anything good yet.
| wpietri wrote:
| Maybe a channel that's for weird problems? They'd still
| have to explicitly post the weird problem, of course, so
| it's not nearly as good. But we get some good serendipity
| in my work Slack when people just post mysterious-to-them
| experiences that they're still working on.
| TickleSteve wrote:
| allow channels to be "overheard", i.e you get notifications
| about messages you're not currently subscribed to.
|
| The problem with channels is that they create silos...
| having a more general chat area is where these kind of
| things happen.
| jasonwatkinspdx wrote:
| It's not equivalent, but people create a similar dynamic
| online. IRC is a great example. Today there's several
| slacks/discords I idle in that are just friends sharing
| what's going on throughout their day. Both contexts have
| advantages and disadvantages imo.
| rgovostes wrote:
| > [At] Bell Labs I came into a very productive department. Bode
| was the department head at the time; [Claude] Shannon was there
| ... I shared an office for a while with Shannon. At the same
| time he was doing information theory, I was doing coding
| theory. It is suspicious that the two of us did it at the same
| place and at the same time - it was in the atmosphere.
|
| -- Richard Hamming
| imoverclocked wrote:
| I wonder if these will be small and cheap enough to create a 2x2
| array of pixels so one could eventually make a focused image.
| napier wrote:
| Appropriate username for posting a story about recently
| declassified tech.
| xavriley wrote:
| I'm not 100% sure, but this tech sounds like a nano scale version
| of "The Thing"
| https://en.m.wikipedia.org/wiki/The_Thing_(listening_device) (a
| passive radio transmitter invented by Leon Theremin)
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