True Wireless Stereo (TWS)  devices will be ready for any acoustic environment in everyday life  


Redefining hearing and communication with TWS earbuds and hearables

<p id="isPasted">Recording technology has followed a path of increasing fidelity since the days of wax grooves on a cylinder with mechanical playback. Later those grooves were carved into vinyl and the music reproduced electrically. Then magnetic tape enhanced the quality of recorded sound from the 1940s through to the 1970s.&nbsp;The analogue era was then brushed aside by digital recording, using technology pioneered by Sony, which peaked with today&rsquo;s CD-quality sound.</p><p>But it turns out that the relentless drive for greater sound quality might have been misplaced. It seems that beyond Hi-Fi aficionados, listeners are happy with digital sound delivered at bitrates well below those offered by CD&mdash;provided it&rsquo;s done cleverly&mdash;and that&rsquo;s proved a boon for wireless audio product designers.</p><h2>The psychology of sound</h2><p>Engineers use coder/encoders (&ldquo;codecs&rdquo;) to stream audio sound across a wireless link. The codecs use a compression format to squeeze the digitized music and lower the throughput required to wirelessly transmit. The compression formats help improve range and lower power consumption.</p><p>Some popular compression techniques use &lsquo;lossy&rsquo; formats whereby before transmission, the encoder discards information considered not needed to maintain the quality of reproduction, in order to increase compression. The developers of lossy formats have been guided by psychoacoustic models which help them determine which information can be discarded. But not all psychoacoustic models are equal and otherwise equivalent compression algorithms can result in very different sound quality.</p><h2>Bluetooth Audio evolves</h2><p>The Bluetooth Special Interest Group (SIG) developed its own wireless streaming technology as far back as 2003.&nbsp;Called the Advanced Audio Distribution Profile (A2DP), the technology facilitated audio streaming between two Bluetooth devices and introduced the low complexity sub-band codec (SBC).</p><p>SBC did a reasonable job but suffered from some drawbacks. Key among these was a channel limitation that only allowed streaming audio to a single device such as the left-hand unit of a pair of earbuds. Engineers overcame the problem by processing the incoming Bluetooth audio stream in one earbud and then from there wirelessly retransmitting the second channel to the other earbud. The technique worked but was processor intensive and shortened battery life.</p><p>Now a new Bluetooth SIG codec, called the Low Complexity Communications Codec (LC3), is both addressing the drawbacks of SBC and bringing some new features of its own. LC3 forms the backbone of <a href="https://www.nordicsemi.com/Products/Bluetooth-LE-Audio?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">LE Audio</a>, which the Bluetooth SIG describes as &ldquo;the future of wireless sound&rdquo;.</p><p>Through innovative compression techniques, LC3 promises improved audio quality and better battery life than SBC for all use cases. A key factor in extending battery life is that LC3 provides the same audio quality as SBC but at half the throughput. LE Audio also brings true wireless stereo (TWS) and other new functions to wireless audio including Audio Sharing.</p><h2>Number crunching power</h2><p>LC3 does demand more computational resource than SBC to compress and decompress the music. Previously that would threaten to erode some of the power advantage gained by the lower throughout for a given audio quality, but the new generation of wireless SoCs provide the answer. Bluetooth LE SoCs such as Nordic Semiconductor&rsquo;s <a href="https://www.nordicsemi.com/Products/nRF5340?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">nRF5340</a> offer plenty of processing power yet at a much lower processor energy consumption than previous generations of chips.</p><p>The nRF5340 features a dedicated Arm Cortex M33 application processor, optimized for performance and with ample overhead to look after the computational demands of advanced audio codecs. The SoC incorporates a second M33 processor to supervise wireless connectivity and which is optimized for low power consumption. The result is an SoC with the ideal combination of performance and energy use to meet the demands of LE Audio.</p><h2>Accelerate wireless audio development</h2><p>Nordic is making it easy for developers to get started on LE Audio projects with its <a href="https://www.nordicsemi.com/nRF5340-Audio-DK?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">nRF5340 Audio DK</a>. The DK makes it easy to embark on LE Audio projects. It is highly configurable allowing it to function as a USB dongle to send and receive high-quality audio data from a PC, a business headset, or a TWS earbud.</p><p>The Audio DK features Nordic&rsquo;s <a href="https://www.nordicsemi.com/Products/nPM1100?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">nPM1100</a> power management IC (PMIC), and Cirrus Logic&rsquo;s CS47L63 Audio digital signal processor (DSP). The PMIC features a highly efficient configurable buck regulator and an integrated battery charger and its extremely small form factor makes it ideal for space-constrained applications like TWS Earbuds. The CS47L63 is optimized for direct connection to an external headphone load and suits earbuds with mono-only and direct speaker output.</p><h2>No trade-offs</h2><p>LE Audio brings no technical trade-offs limiting what a designer can do. It brings better audio quality, more robust wireless connectivity and vastly improved battery life compared with Classic Audio. An engineer can, for example, design earbuds with incredible sound quality and extended battery life by designing with LE Audio. Alternatively, they can use smaller batteries to shrink the product&rsquo;s form factor and direct material costs, while still matching the original product&rsquo;s playtime.</p><p>And with the nRF5340 Audio DK and Nordic&rsquo;s nRF5340 SoC, getting those compelling wireless audio products to market quickly is made easy.</p><hr><p>This article was first published on Nordic&#39;s&nbsp;<a href="https://blog.nordicsemi.com/getconnected" target="_blank" rel="nofollow" id="isPasted"></a><a href="https://blog.nordicsemi.com/getconnected?utm_campaign=2021%20wevolver" rel="nofollow" target="_blank">Get Connected Blog</a>.  &nbsp;</p>

Technology described as the ‘future of wireless sound’ allows engineers to enhance the sound quality and power consumption of wireless audio products

LE Audio ready for developers of next-generation wireless sound products

<p>In this episode, we talk about why minimization of speakers and energy storage devices is crucial for the next generation of electronics and medical devices. As always, you can find these and other interesting &amp; impactful engineering articles on Wevolver.com.&nbsp;</p><p><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/85cb7aef-c9a6-4ef8-b1e2-47bc45441f6d?dark=false" class="fr-draggable" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span></p><hr><p id="isPasted">This podcast is sponsored by <a href="https://www2.mouser.com/" rel="nofollow" target="_blank">Mouser Electronics</a>. &nbsp; &nbsp;&nbsp;</p><p><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1654599330909-Mouser-sponsor-1-a.jpg" style="width: 766px;" class="fr-fic fr-dib"></p><hr><h3 id="isPasted">EPISODE NOTES</h3><p>(0:50) -&nbsp;<a href="https://www.wevolver.com/article/ultrathin-fuel-cell-uses-the-bodys-own-sugar-to-generate-electricity" target="_blank">Glucose Fuel Cell</a></p><p>(13:46) - <a href="https://www.wevolver.com/article/researchers-develop-a-paper-thin-loudspeaker" target="_blank">Paper-thin Loudspeaker</a></p><hr><p id="isPasted">About the podcast:</p><p>Every day, some of the most innovative universities, companies, and individual technology developers share their knowledge on Wevolver. To ensure we can also provide this knowledge for the growing group of podcast listeners, we started a collaboration with two young engineers, Daniel Scott Mitchell &amp; Farbod Moghaddam who discuss the most interesting content in this podcast series.&nbsp;</p><p>To learn more about this show, please visit the&nbsp;<a href="https://www.wevolver.com/profile/the.next.byte" target="_blank">shows page</a>. By following the page, you will get automatic updates by email when a new show is published.</p><p>Be sure to give us a follow and review on&nbsp;<a href="https://podcasts.apple.com/nl/podcast/the-next-byte/id1548255861?l=en" rel="nofollow" target="_blank">Apple</a> podcasts,&nbsp;<a href="https://open.spotify.com/show/6lPPsRtegnivsRUEsQ09R7?si=IPMiah7xT_apJtPjqvXMlA" rel="nofollow" target="_blank">Spotify</a>, and most of your favorite podcast platforms!</p><p>Take a few seconds to leave us a review. It really helps!&nbsp;<a href="https://apple.co/2RIsbZ2" rel="nofollow" target="_blank">https://apple.co/2RIsbZ2&nbsp;</a>if you do it and send us proof, we&rsquo;ll give you a shoutout on the show.</p>

Silicon chip with 30 individual glucose micro fuel cells, seen as small silver squares inside each gray rectangle. Image: Kent Dayton

In this episode, we talk about why minimization of speakers and energy storage devices is crucial for the next generation of electronics and medical devices. 

Podcast: Nanometer Fuel Cells & Ultrathin Speakers

<p id="isPasted">Researchers at the National Institute of Standards and Technology (NIST) have boosted the sensitivity of their atomic radio receiver a hundredfold by enclosing the small glass cylinder of cesium atoms inside what looks like custom copper &ldquo;headphones.&rdquo;&nbsp;</p><p>The structure &mdash; a square overhead loop connecting two square panels &mdash; increases the incoming radio signal, or electric field, applied to the gaseous atoms in the flask (known as a vapor cell) between the panels. This enhancement enables the radio receiver to detect much weaker signals than before. The demonstration is described in <a data-extlink="" href="https://aip.scitation.org/doi/10.1063/5.0088532" target="_blank">a new paper</a>.&nbsp;</p><p>The headphone structure is technically a split-ring resonator, which acts like a metamaterial &mdash; a material engineered with novel structures to produce unusual properties. &ldquo;We can call it a metamaterials-inspired structure,&rdquo; NIST project leader Chris Holloway said.&nbsp;</p><p>NIST researchers previously demonstrated the <a data-entity-substitution="canonical" data-entity-type="node" data-entity-uuid="54d690a3-031e-4c90-8b58-0a466ba93097" href="https://www.nist.gov/news-events/news/2019/09/nist-team-shows-atoms-can-receive-common-communications-signals" target="_blank" title="NIST Team Shows Atoms Can Receive Common Communications Signals">atom-based radio receiver</a>. An atomic sensor has the potential to be physically smaller and work better in noisy environments than conventional radio receivers, among other possible advantages.&nbsp;</p><p>The vapor cell is about 14 millimeters (mm) long with a diameter of 10 mm, roughly the size of a fingernail or computer chip, but thicker. The resonator&rsquo;s overhead loop is about 16 mm on a side, and the ear covers are about 12 mm on a side.</p><p>The NIST radio receiver relies on a special state of the atoms. Researchers use two different color lasers to prepare atoms contained in the vapor cell into high-energy (&quot;Rydberg&quot;) states, which have novel properties such as extreme sensitivity to electromagnetic fields. The frequency and strength of an applied electric field affects the colors of light absorbed by the atoms, and this has the effect of converting the signal strength to an optical frequency that can be measured accurately.</p><p>A radio signal applied to the new resonator creates currents in the overhead loop, which produces a magnetic flux, or voltage. The dimensions of the copper structure are smaller than the radio signal&rsquo;s wavelength. As a result, this small physical gap between the metal plates has the effect of storing energy around the atoms and enhancing the radio signal. This boosts performance efficiency, or sensitivity.</p><p>&ldquo;The loop captures the incoming magnetic field, creating a voltage across the gaps,&rdquo; Holloway said. &ldquo;Since the gap separation is small, a large electromagnetic field is developed across the gap.&rdquo;</p><p>The loop and gap sizes determine the natural, or resonant, frequency of the copper structure. In the NIST experiments the gap was just over 10 mm, limited by the outside diameter of the available vapor cell. The researchers used a commercial mathematical simulator to determine the loop size needed to create a resonant frequency near 1.312 gigahertz, where Rydberg atoms switch between energy levels.&nbsp;</p><p>Several outside collaborators helped model the resonator design. Modeling suggests the signal could be made 130 times stronger, whereas the measured result was roughly a hundredfold, likely due to energy losses and imperfections in the structure. A smaller gap would produce greater amplification. The researchers plan to investigate other resonator designs, smaller vapor cells and different frequencies.&nbsp;</p><p>With further development, atom-based receivers may offer many benefits over conventional radio technologies. For example, the atoms act as the antenna, and there is no need for traditional electronics that convert signals to different frequencies for delivery because the atoms do the job automatically. The atom receivers can be physically smaller, with micrometer-scale dimensions. In addition, atom-based systems may be less susceptible to some types of interference and noise.&nbsp;</p><p>Modeling assistance was provided by collaborators from the University of Texas, Austin; City University of New York, N.Y.; and University of Technology Sydney, Australia.</p><hr><p>Paper: C.L. Holloway, N. Prajapati, A.B. Artusio-Glimpse, S. Berweger, M.T. Simons, Y. Kasahara, A. Alu and R.W. Ziolkowski. Rydberg atom-based field sensing enhancement using a split-ring resonator. <em>Applied Physics Letters.</em> Published online May 20, 2022. DOI: <a data-extlink="" href="https://doi.org/10.1063/5.0088532" target="_blank">10.1063/5.0088532</a></p><p><style type="text/css" id="isPasted"></style><style type="text/css"></style><span data-sheets-userformat='{"2":513,"3":{"1":0},"12":0}' data-sheets-value='{"1":2,"2":"This article was first published here"}'>This article was first published here:&nbsp;<a href="https://www.nist.gov/news-events/news/2022/05/custom-headphones-boost-atomic-radio-reception-100-fold" id="isPasted" rel="noopener noreferrer" target="_blank">https://www.nist.gov/news-events/news/2022/05/custom-headphones-boost-atomic-radio-reception-100-fold</a></span></p>

Copper “headphones” boost the sensitivity of NIST’s atomic radio receiver, which is composed of a gas of cesium atoms prepared in a special state inside the glass container. When an antenna located above the setup sends down a radio signal, the headphones boost the strength of the received signal a hundredfold.  Credit: NIST

Researchers at the National Institute of Standards and Technology (NIST) have boosted the sensitivity of their atomic radio receiver a hundredfold by enclosing the small glass cylinder of cesium atoms inside what looks like custom copper “headphones.” 

Custom 'Headphones' Boost Atomic Radio Reception 100-Fold

<p>This article was discussed in our <a data-saferedirecturl="https://www.google.com/url?q=https://www.wevolver.com/profile/the.next.byte&source=gmail&ust=1654577502725000&usg=AOvVaw17DYESu9H53oY-k8Bg1xYc" href="https://www.wevolver.com/profile/the.next.byte" id="isPasted" rel="noopener noreferrer" target="_blank">Next Byte podcast</a>.&nbsp;</p><p><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe height="200px" width="100%" frameborder="no" scrolling="no" seamless="" src="https://player.simplecast.com/85cb7aef-c9a6-4ef8-b1e2-47bc45441f6d?dark=false" class="fr-draggable" data-gtm-yt-inspected-9="true" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true"></iframe></span></p><p>The full article will continue below.</p><hr><p>This article was first published on <a href="https://news.mit.edu/2022/low-power-thin-loudspeaker-0426" id="isPasted" rel="noopener noreferrer" target="_blank">MIT News</a>. &nbsp;</p><hr><p id="isPasted">MIT engineers have developed a paper-thin loudspeaker that can turn any surface into an active audio source.</p><p>This thin-film loudspeaker produces sound with minimal distortion while using a fraction of the energy required by a traditional loudspeaker. The hand-sized loudspeaker the team demonstrated, which weighs about as much as a dime, can generate high-quality sound no matter what surface the film is bonded to.</p><p>To achieve these properties, the researchers pioneered a deceptively simple fabrication technique, which requires only three basic steps and can be scaled up to produce ultrathin loudspeakers large enough to cover the inside of an automobile or to wallpaper a room.</p><p>Used this way, the thin-film loudspeaker could provide active noise cancellation in clamorous environments, such as an airplane cockpit, by generating sound of the same amplitude but opposite phase; the two sounds cancel each other out. The flexible device could also be used for immersive entertainment, perhaps by providing three-dimensional audio in a theater or theme park ride. And because it is lightweight and requires such a small amount of power to operate, the device is well-suited for applications on smart devices where battery life is limited.</p><p>&ldquo;It feels remarkable to take what looks like a slender sheet of paper, attach two clips to it, plug it into the headphone port of your computer, and start hearing sounds emanating from it. It can be used anywhere. One just needs a smidgeon of electrical power to run it,&rdquo; says Vladimir Bulović, the Fariborz Maseeh Chair in Emerging Technology, leader of the Organic and Nanostructured Electronics Laboratory (ONE Lab), director of MIT.nano, and senior author of the paper.</p><p>Bulović wrote the paper with lead author Jinchi Han, a ONE Lab postdoc, and co-senior author Jeffrey Lang, the Vitesse Professor of Electrical Engineering. The research is published today in <em>IEEE Transactions of Industrial Electronics</em>.</p><h2><strong>A new approach</strong></h2><p>A typical loudspeaker found in headphones or an audio system uses electric current inputs that pass through a coil of wire that generates a magnetic field, which moves a speaker membrane, that moves the air above it, that makes the sound we hear. By contrast, the new loudspeaker simplifies the speaker design by using a thin film of a shaped piezoelectric material that moves when voltage is applied over it, which moves the air above it and generates sound.</p><p>Most thin-film loudspeakers are designed to be freestanding because the film must bend freely to produce sound. Mounting these loudspeakers onto a surface would impede the vibration and hamper their ability to generate sound.</p><p>To overcome this problem, the MIT team rethought the design of a thin-film loudspeaker. Rather than having the entire material vibrate, their design relies on tiny domes on a thin layer of piezoelectric material which each vibrate individually. These domes, each only a few hair-widths across, are surrounded by spacer layers on the top and bottom of the film that protect them from the mounting surface while still enabling them to vibrate freely. The same spacer layers protect the domes from abrasion and impact during day-to-day handling, enhancing the loudspeaker&rsquo;s durability.</p><p>To build the loudspeaker, the researchers used a laser to cut tiny holes into a thin sheet of PET, which is a type of lightweight plastic. They laminated the underside of that perforated PET layer with a very thin film (as thin as 8 microns) of piezoelectric material, called PVDF. Then they applied vacuum above the bonded sheets and a heat source, at 80 degrees Celsius, underneath them.</p><p>Because the PVDF layer is so thin, the pressure difference created by the vacuum and heat source caused it to bulge. The PVDF can&rsquo;t force its way through the PET layer, so tiny domes protrude in areas where they aren&rsquo;t blocked by PET. These protrusions self-align with the holes in the PET layer. The researchers then laminate the other side of the PVDF with another PET layer to act as a spacer between the domes and the bonding surface.</p><p>&ldquo;This is a very simple, straightforward process. It would allow us to produce these loudspeakers in a high-throughput fashion if we integrate it with a roll-to-roll process in the future. That means it could be fabricated in large amounts, like wallpaper to cover walls, cars, or aircraft interiors,&rdquo; Han says.</p><p><span class="fr-video fr-deletable fr-fvc fr-dvb fr-draggable" contenteditable="false" draggable="true"><iframe src="https://www.youtube.com/embed/pABxdxTuAY8?&wmode=opaque&rel=0&enablejsapi=1&origin=https://www.wevolver.com" frameborder="0" allowfullscreen="" class="fr-draggable" data-lf-yt-playback-inspected-kn9eq4roawkarlvp="true" style="width: 767px; height: 438px;" data-gtm-yt-inspected-9="true" id="307239093"></iframe></span></p><h2 id="isPasted"><strong>High quality, low power</strong></h2><p>The domes are 15 microns in height, about one-sixth the thickness of a human hair, and they only move up and down about half a micron when they vibrate. Each dome is a single sound-generation unit, so it takes thousands of these tiny domes vibrating together to produce audible sound.</p><p>An added benefit of the team&rsquo;s simple fabrication process is its tunability &mdash; the researchers can change the size of the holes in the PET to control the size of the domes. Domes with a larger radius displace more air and produce more sound, but larger domes also have lower resonance frequency. Resonance frequency is the frequency at which the device operates most efficiently, and lower resonance frequency leads to audio distortion.</p><p>Once the researchers perfected the fabrication technique, they tested several different dome sizes and piezoelectric layer thicknesses to arrive at an optimal combination.</p><p>They tested their thin-film loudspeaker by mounting it to a wall 30 centimeters from a microphone to measure the sound pressure level, recorded in decibels. When 25 volts of electricity were passed through the device at 1 kilohertz (a rate of 1,000 cycles per second), the speaker produced high-quality sound at conversational levels of 66 decibels. At 10 kilohertz, the sound pressure level increased to 86 decibels, about the same volume level as city traffic.</p><p>The energy-efficient device only requires about 100 milliwatts of power per square meter of speaker area. By contrast, an average home speaker might consume more than 1 watt of power to generate similar sound pressure at a comparable distance.</p><p>Because the tiny domes are vibrating, rather than the entire film, the loudspeaker has a high enough resonance frequency that it can be used effectively for ultrasound applications, like imaging, Han explains. Ultrasound imaging uses very high frequency sound waves to produce images, and higher frequencies yield better image resolution. &nbsp;</p><p>The device could also use ultrasound to detect where a human is standing in a room, just like bats do using echolocation, and then shape the sound waves to follow the person as they move, Bulović says. If the vibrating domes of the thin film are covered with a reflective surface, they could be used to create patterns of light for future display technologies. If immersed in a liquid, the vibrating membranes could provide a novel method of stirring chemicals, enabling chemical processing techniques that could use less energy than large batch processing methods.</p><p>&ldquo;We have the ability to precisely generate mechanical motion of air by activating a physical surface that is scalable. The options of how to use this technology are limitless,&rdquo; Bulović says.</p><p>&ldquo;I think this is a very creative approach to making this class of ultra-thin speakers,&rdquo; says Ioannis (John) Kymissis, Kenneth Brayer Professor of Electrical Engineering and Chair of the Department of Electrical Engineering at Columbia University, who was not involved with this research. &ldquo;The strategy of doming the film stack using photolithographically patterned templates is quite unique and likely to lead to a range of new applications in speakers and microphones.&rdquo;</p><hr><p>&quot;Reprinted with permission of <a href="https://news.mit.edu/2022/low-power-thin-loudspeaker-0426" id="isPasted" rel="noopener noreferrer" target="_blank">MIT News</a>&quot;&nbsp;</p>

MIT researchers have developed an ultrathin loudspeaker that can turn any rigid surface into a high-quality, active audio source. The straightforward fabrication process they introduced can enable the thin-film devices to be produced at scale. Image: Felice Frankel

MIT engineers have developed a paper-thin loudspeaker that can turn any surface into an active audio source.

Researchers develop a paper-thin loudspeaker

<p id="isPasted">Bluetooth 5’s benefits are about much more than increased speed and extended range. Low energy advertising extensions are also a major enhancement.</p><p>Advertisements are used by devices to broadcast data and information that can be discovered and processed by observer devices. This means information can be broadcast to multiple devices at the same time, as opposed to Bluetooth connections, which only allow peer-to-peer communication.</p><h2>Improvements in Bluetooth 5</h2><p>The release of the Bluetooth 5 specification promised new functionality for connectionless services such as location-relevant information and navigation. By adding significantly more capacity to advertising packets, Bluetooth 5 aims to quicken the deployment of beacons and location-based services to users around the world.</p><p>Advertising extensions in Bluetooth 5 provide the capability to offload advertising data from the three traditional advertising channels to the full set of data channels for more frequency diversity. More efficient use of the 2.4 GHz band should enable developers to increase the rate of advertised packets, as well as utilize the new PHY modes, paving the way for better streaming and beacon solutions.</p><p>All these LE PHY’s supported by Bluetooth 5 can be used for advertisements with the introduction of advertising extensions:</p><ul><li>LE 1M PHY: 1 Mb/s bit rate, 1 Msym/s symbol rate. Each bit maps to a single radio symbol. The same PHY as used in Bluetooth 4.0.</li><li>Coded PHY: 1 Mb/s bit rate, 500 or 125 ksym/s symbol rate. Each bit is coded into 2 or 8 bits using a forward error correction algorithm to provide higher tolerance for bit errors, resulting in improved range.</li><li>LE 2M PHY: 2 Mb/s bit rate, 2 Msym/s symbol rate. Doubles the symbol rate to increase the speed, at a small cost to range.</li></ul><h2>Extended Advertisements</h2><p>In Bluetooth 4.0, all advertising was done on just three channels. Bluetooth 5 improves this mechanism by allowing a small header packet sent on the three primary advertising channels to point to a larger payload sent at a later time on one of the 37 data channels.</p><p>This removes the need to duplicate the data payload on all three advertising channels, while allowing considerably more advertising data in the area before running into coexistence issues.</p><p>The specification for extended advertisements in Bluetooth 5 is almost as large as the entire original Bluetooth 4.0 specification. There are some key differences to understand before delving into development, including:</p><ul><li>A single advertising packet can hold up to 255 bytes of data, up from 37 in Bluetooth 4.0</li><li>Advertising packets can now be chained together, allowing for even larger beacon payloads than with a single packet (a chain can hold a maximum of 1650 bytes)</li><li>Advertising packets can be sent periodically, allowing observers to lock on to a stream of advertised packets</li><li>Periodic advertisements can be combined with chained packets, allowing an even higher overall data throughput</li></ul><p>Because older devices that don’t support Bluetooth 5 will not be able to discover extended advertisements, an advertising set with legacy advertising PDUs for older scanning devices should also be used, at least until Bluetooth 5 supported hardware is commonplace in the market.</p><h2>Bluetooth Advertising and beacons</h2><p>Beacons can now broadcast more data and allow for a better user experience. Connectable devices can also utilize this to send more data and allow connections on the secondary advertising channels (which can help avoid interference and noise from other devices broadcasting on the primary channels).</p><p>Although beacon applications stand to benefit most from these extended advertisements, there will be a wait involved until relevant devices such as smartphones and tablets fully support Bluetooth 5 advertising extensions. It's a wait that will be worthwhile, as there is a big potential for new applications and for the use of Bluetooth in more markets.</p><h2>Beyond Bluetooth 5</h2><p>The development of the Bluetooth standard didn’t stop with version 5, and subsequent updates have brought new features and improvements.</p><p>The 5.1 version focused primarily on adding direction-finding support to serve the indoor positioning use case where Bluetooth beacons need to be located with a high degree of accuracy.</p><p>The headline feature of version 5.2 was support for LE Audio, which improves the existing audio support in Bluetooth, aiming to increase battery life, sound quality, and feature set for Bluetooth audio applications.</p><p><br>Common for both of these features is that they leverage the advertising extension functionality added in version 5 in new ways. Depending on the use case, both direction finding and LE Audio can be used either in a broadcasting or a connected mode. When broadcasting is needed, advertising extensions will provide the data throughput and flexibility required by these two features.</p><p>Future updates to the specification will likely find even more ways to utilize advertising extensions, making this an integral part of many different Bluetooth products.<br><br><em>This is an updated version of an article first published in December 2017.</em></p><hr><p>This article was first published on Nordic's&nbsp;<a href="https://blog.nordicsemi.com/getconnected" target="_blank" rel="nofollow" id="isPasted"></a><a href="https://blog.nordicsemi.com/getconnected?utm_campaign=2021%20wevolver" rel="nofollow" target="_blank">Get Connected Blog</a>. </p>

Bluetooth 5’s benefits are about much more than increased speed and extended range. Low energy advertising extensions are also a major enhancement.

Bluetooth 5 Advertising Extensions

<p id="isPasted">People living with disabilities don't want special treatment; they want equal opportunity. The ability to act independently of, and at the same time connect with, others when moving, communicating, learning, working, and socializing.</p><p>Technology is making this increasingly viable, as assistive and adaptive technologies create a more accessible world for people living with a range of disabilities, including limb differences, motor neuron disease, as well as the blind and deaf.</p><p>Much of this development has focused on smartphones and computers, but wireless IoT technology also plays its role.</p><h2>The world around us</h2><p>Connected technologies such as environmental sensors, smart objects, and wearables are powerful tools. They can provide various inclusive and assistive information services in near real-time and connect people with disabilities with their work, home, and other environments:</p><ul><li>Indoor and outdoor wayfinding solutions employing computer vision, augmented reality, and wireless optical communications are assisting the visually impaired navigate their way from home to work and back again</li><li>Clothing embedding haptic stimulation sensors can enable the deaf to 'feel the beat' of a musical performance</li><li>Robotic limbs and bionic exoskeletons are giving the wearer control of their environment and the ability to stand and walk</li></ul><h2>Wearables for tackling MND</h2><p>Nordic Semiconductor has been working closely with customers who develop wireless solutions for those living with a disability. One such company is Control Bionics, whose wearable assistive technology offers people with amyotrophic lateral sclerosis (ALS)—also known as motor neuron disease (MND)—the ability to communicate despite paralysis or loss of speech. The small, non-invasive sensor is placed on the skin over the muscle chosen to be the switch. When the user attempts to move that muscle, the device interprets the signals sent from the brain to the muscle and uses those signals to control a paired computer, tablet, or smartphone wirelessly.</p><h2>Bluetooth LE bionic arms</h2><p>Another example is U.S. non-profit organization, Limbitless Solutions, which creates personalized bionic arms for children suffering from limb differences. The prosthetic limbs employ electromyographic (EMG) sensors to pick up signals generated by muscle movements in the wearer's upper arm. The forearm section of the bionic arm contains a battery pack that powers the motors controlling the different movements, while the hand unit includes the core electronics and motors for the fine control of the individual fingers. Bluetooth LE connectivity enables set-up, adjustment, and monitoring of the arm from a smartphone app, for example, to precisely determine the degree of muscle flexing required to generate a certain force in the fingers, and to help the child learn how to manipulate their new arm.</p><h2>Next-gen connectivity solutions</h2><p>Bluetooth LE wireless connectivity and next-generation SoCs play an essential role in ensuring the viability of these and other technologies for end-users living with disabilities. They provide a low latency wireless link to a smartphone or tablet for ease of control, and also low power consumption in an ultra-miniaturized form factor.</p><p>Avoiding having to charge our devices frequently is a significant advantage to any user, and none of us want a clunky wearable that is uncomfortable to wear. Still, the benefits are more fundamental when that device is in near-constant use or is relied upon for daily life. For example, bionic arms must be comfortable, lightweight, and easy to use, particularly for children. Smartwatches for the blind, meanwhile, must be able to last at least a full day on a single charge.</p><p>As these assistive technologies become more sophisticated and ambitious in their scope, wireless SoCs will need to keep pace. Nordic's new nRF53 Series has been designed to meet the likely requirements of developers in the future. It offers a new flexible, dual-processor hardware architecture, low power, and the ability to support miniaturized machine learning, edge processing, and LE Audio.</p><h2>The promise of LE Audio</h2><p>LE Audio, for instance, has the potential to significantly improve the experience of users of hearing aids and hearing implants by supporting a feature called Audio Sharing. Thanks to LE Audio, people with hearing loss will be able to realize the same benefits of Bluetooth audio enjoyed by users of standard Bluetooth headphones and earbuds, including wireless calling, listening, and watching. Audio Sharing will enable an advanced new type of Assistive Listening Systems with higher audio quality and greater privacy that avoids the challenges of sound quality, spill-over (magnetic interference created by multiple hearing loops in close proximity), and costs of current systems.</p><p>Wireless technology exists now, and it can provide disabled users with the ability to participate in all aspects of life on more equal terms than previously possible.&nbsp;</p><hr><p>This article was first published on Nordic's&nbsp;<a href="https://blog.nordicsemi.com/getconnected" target="_blank" rel="nofollow" id="isPasted"></a><a href="https://blog.nordicsemi.com/getconnected?utm_campaign=2021%20wevolver" rel="nofollow" target="_blank">Get Connected Blog</a>. </p>

People living with disabilities don't want special treatment; they want equal opportunity. The ability to act independently of, and at the same time connect with, others when moving, communicating, learning, working, and socializing.

Connected IoT tech promotes accessibility for all

<p id="isPasted">Despite specific industries experiencing slowdowns caused by the Covid-19 pandemic, projections in the Bluetooth technology market are optimistic through the remainder of 2021 and beyond.</p><p>Annual shipments of Bluetooth-enabled devices are expected to grow at a compound annual growth rate (CAGR) of 10 percent over the next five years, reaching 6.4 billion in 2025. More specifically, 70 percent of these shipments in 2025 will be peripheral devices such as earbuds, wearables, sensors, and smart lights – clearly outpacing platform-device shipments (for example, phones, tablets, and PCs) by three to one.</p><p>These forecasts headline the Bluetooth Special Interest Group's (SIG) 2021 <a href="https://www.bluetooth.com/bluetooth-resources/2021-bmu/" rel="noopener" target="_blank">Bluetooth® Market Update</a>, based primarily on analysis by ABI Research, which also points to an impressive upturn for different Bluetooth technologies across various verticals.</p><h2>Market shifts further towards Bluetooth LE</h2><p>Bluetooth Classic has peaked, and dual-mode devices (supporting both Bluetooth Classic and LE capabilities) are rising. Still, current trends suggest a marked increase in Bluetooth LE-only solutions. Shipments of these single-mode devices are expected to triple over the next five years, states the latest Bluetooth SIG report.</p><p>In particular, <a href="https://www.nordicsemi.com/Products/Bluetooth-Low-Energy?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">Bluetooth LE</a> will prove a dominant protocol among the global consumer electronic devices sector. The anticipation is that 96 percent of devices will include Bluetooth LE by 2025, primarily due to its prevalence in phones, tablets, and computers. A range of new features supported by Bluetooth LE also contributes to its forecast growth.</p><h2>Bluetooth LE Audio announces its arrival</h2><p>Over the past year, Bluetooth audio streaming has accounted for 1.3 billion shipments in 2021. The forecast for this solution area is to achieve 1.5 x growth from 2021 through 2025, reaching 1.7 billion annual shipments in 2025. Most of these shipments comprise headphones, with 633 million transported in 2021 alone. Demand for Bluetooth speakers will see shipments increase from 350 million in 2021 to 423 million in 2025.</p><p>But the launch of <a href="https://www.nordicsemi.com/Products/Bluetooth-LE-Audio?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">Bluetooth LE Audio</a> will take global Bluetooth audio to another level. Bluetooth LE Audio enhances Bluetooth Classic audio by providing higher quality audio streaming with longer battery life for speakers and headphones. And the prevalence of Bluetooth LE means Bluetooth LE Audio is likely to lead the way in audio streaming worldwide, with earbuds shipments alone forecast to see 3.4 x growth to 521 million by 2025.</p><p>Yet this is only the beginning of what Bluetooth LE Audio can make possible. The technology will include the Bluetooth Audio Sharing feature, enabling use cases where, for example, multiple headphones connect to a single audio stream. Bluetooth Audio Sharing might make public audio more accessible for the 1.5 billion people worldwide living with some form of hearing loss (figures from the World Health Organization). Utilized at conference centers, airports, and other public venues, it can form low-cost assistive listening systems by transmitting the audio stream directly to in-ear Bluetooth hearing assistance devices. More than 92 million such devices are expected to ship annually by 2024, according to Juniper Research.</p><p>Bluetooth LE Audio demands high-end processing capabilities. Nordic's <a href="https://www.nordicsemi.com/Products/nRF5340?utm_campaign=2021%20wevolver" rel="noopener noreferrer" target="_blank">nRF5340 SoC</a> includes a new, flexible dual-processor hardware architecture with advanced security features designed to meet the Bluetooth LE multi-stream synchronized audio requirements.</p><h2>High-end processing supports advanced audio</h2><p>Bluetooth LE Audio is set to change the way we listen, but what drives the technology itself? Bluetooth LE Audio works through compressing the necessary data using an algorithm known as a Low Complexity Communication Codec (LC3) to reduce the throughput. Once received, another algorithm decompresses the data, allowing users to stream the same audio quality at reduced bitrates. This design also makes the creation of untethered earphones easier, as both can receive the stream with synchronized playback (through isochronous channels) instead of the old point-to-point stream.</p><h2>Bluetooth Location Services</h2><p>The Bluetooth Location Services market is also moving in the right direction. Expectations for the segment are to exhibit healthy medium-term expansion, with 32 percent CAGR in annual device shipments from 2021 to 2025.</p><p>According to the report, retail is the vertical taking the most significant advantage of Bluetooth Location Services, with 66 percent of all implementations currently supporting retail use cases. At the same time, 79 percent of Bluetooth Location Services solutions include indoor navigation properties. For example, 136 million Bluetooth RTLS tags and personal trackers will ship in 2021, the report claims, with 4 x growth in asset tracking tag shipments and 5 x growth in Bluetooth healthcare location services implementations predicted by 2025. The effects of the pandemic primarily spur the latter.</p><p>As wireless innovation continues in the face of recent challenges, resilient Bluetooth technology is powering its way into the future.</p><hr><p>This article was first published on Nordic's&nbsp;<a href="https://blog.nordicsemi.com/getconnected" target="_blank" rel="nofollow" id="isPasted"></a><a href="https://blog.nordicsemi.com/getconnected?utm_campaign=2021%20wevolver" rel="nofollow" target="_blank">Get Connected Blog</a>. </p>

Despite specific industries experiencing slowdowns caused by the Covid-19 pandemic, projections in the Bluetooth technology market are optimistic through the remainder of 2021 and beyond.

Continued growth forecast for resilient Bluetooth and LE Audio technology

<p>USound currently offers two MEMS loudspeakers that are part of the Ganymede series: Adap UT-P2019 and Achelous UT-P2018. Adap is optimized towards maximum acceleration, making it ideal for free-field applications, whereas Achelous is optimized towards maximum excursion, making it especially suitable for occluded-ear applications. Therefore, USound MEMS loudspeakers can be evaluated in both acoustic domains: baffle and coupler conditions. For baffle conditions, the IEC 60268-5 standard is used, while for coupler conditions, the relevant standard is the IEC 60318-4, formerly known as 60711, or simply &ldquo;711&rdquo;. For both setups, proprietary measurement adapters are used to fit USound speakers to the standardized setup. Using the adapters, it is possible to achieve the results shown on the Adap and Achelous datasheets. Measurements with the Carme Box UJ-R1020 can also assess the speakers&rsquo; performance even if they lead to slightly different results. In this article, we will show several possibilities to perform the measurements and the differences between those methods.</p><h2 id="isPasted"><strong>BAFFLE MEASUREMENT (IEC&nbsp;60268-5)</strong></h2><p>To measure the loudspeaker in a<strong>&nbsp;</strong>baffle<strong>,</strong> it is necessary to place the MEMS speaker inside the measurement adapter. The following picture shows a drawing of the proprietary adapter used by&nbsp;USound.</p><figure><img data-fr-image-pasted="true" src="https://lh4.googleusercontent.com/J5XLouoWSuShn2kNsrXZlX7cw0jFZl5jQrjSL1EdbaFMATh5sfK1oVCd4B3D4nkMQWXAM0cgZFBTtXlW445rnkRFSDvZ_OB4v7qyiR53GGHtAIHN67NhwYzjFeitd6NnvWBOIlvs" alt="" class="fr-fic fr-dii"></figure><p>The electronic connection is achieved using pogo pins that press against the pads on the back of the loudspeaker. A gasket is placed in front of the speaker for sealing purposes, and an opening in the baffle enables the speaker to radiate towards the microphone, which is placed at a 10 cm distance from the baffle (as per the IEC 60268-5 standard). The SPL and THD results measured with this setup can be found on the&nbsp;<a href="https://www.usound.com/technical-documentation/" target="_blank">Adap UT-P2019&nbsp;datasheet</a>.</p><h3><strong>COUPLER MEASUREMENT (IEC&nbsp;60318-4)</strong></h3><p>For coupler measurements, a coupler adapter was designed to place the speaker close to the coupler without introducing additional resonances. This was obtained using a port of 3.6 mm diameter and 1.5 mm length (with an additional gasket of 0.5 mm, compressed to 0.3 mm). By using these dimensions, any emerging resonance is guaranteed to fall above the audible frequency range (&gt;20 kHz). With the use of USound&rsquo;s coupler adapter, the measurement can be performed without the earmold adapter. The SPL and THD results measured with this setup can be found on the&nbsp;<a href="https://www.usound.com/technical-documentation/" target="_blank">Achelous UT-P2018 datasheet.&nbsp;</a></p><h2>MEASURING MEMS SPEAKERS WITH THE CARME UJ-R1020 SPEAKER&nbsp;BOX.</h2><p>The two methods mentioned above require the use of proprietary coupler adapters. Another possibility to measure USound loudspeakers is by using the Carme UJ-R1020 speaker box. With a back volume of 100 mm&sup3;, it provides the necessary sealing to avoid an acoustic short circuit. It offers a convenient way to connect USound MEMS speakers to USound&lsquo;s linear amplifier Amalthea UA-R3010 or to the Helike UA-E3010 development board. With the Carme speaker box, both measurements in free-field and measurement on an artificial ear are&nbsp;possible.</p><h3><strong>MEASUREMENT WITH CARME BOX IN&nbsp;FREE-FIELD</strong></h3><figure><img data-fr-image-pasted="true" src="https://lh4.googleusercontent.com/U5uzyqnZLWRpXlwc1Gtv94bUBUlLcpX3s9UJe1VlHTHF_9lVpc0SFpNX6beQXZZ9-pAwYi3JtRSSDJryAP7TG87oB2c9DlVplTXJkcbf4DDb6Be2K3hJUxZLcoDwHzkSkSeDYsp0" alt="" class="fr-fic fr-dii"></figure><p>The box must be placed in a reflection-free space such as an anechoic chamber and pointed towards the microphone. Since no baffle is used in this setup and a back volume is introduced, the frequency response will be different from the results present on the Adap datasheet. Due to the missing baffle, the SPL will be ~6 dB lower below resonance frequency. The following graph compares the results obtained with the USound coupler adapter and with Carme&nbsp;Box.</p><figure><img data-fr-image-pasted="true" src="https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box-1024x409.png" alt="" srcset="https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box-1024x409.png 1024w, https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box-300x120.png 300w, https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box-768x307.png 768w, https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box-1536x614.png 1536w, https://www.usound.com/wp-content/uploads/2021/07/Adap-UT-P2019-SPL-measurement-in-the-Carme-speaker-box.png 2048w" sizes="(max-width: 1024px) 100vw, 1024px" class="fr-fic fr-dii" style="height: 300px;"><figcaption>Adap UT-P2019 SPL measurement in the Carme UJ-R1020 test box in free field</figcaption></figure><h4><strong>Measurement with Carme Box in a&nbsp;coupler</strong></h4><p>For coupler measurements, two setups are possible: with or without the earmould adapter. Therefore, the Carme UJ-R1020 box can be placed directly on the base part of the coupler or the earmould adapter, as shown in the following picture.&nbsp;</p><figure><img data-fr-image-pasted="true" src="https://lh4.googleusercontent.com/cW1VA3oRLSVzuCXuaaqTYz517VDH1PopwuEFtUNawEpoylpEmP7GkF3flRI7wmd1ptO-tgEIjBXap-lFYdmIcyO1_1njwZiwsStlFh9orP6DNuDWjewiBWte62oKzpxwD4WZtR2J" alt="" class="fr-fic fr-dii"></figure><figure><img data-fr-image-pasted="true" src="https://lh4.googleusercontent.com/iJ9Fsql8g_vE7FFd00DiJcy4zhFNG_TelJwJ5L79xjxKP_lA99pWIZ_1rv9uxcwK58lwGF_mtHWCZGEIgnG5L8MY-RKepYMYQ3ZzBQlYZcHrGkC6ZB5YCAKcELRQb6YyQ4DDF-Y1" alt="" class="fr-fic fr-dii"></figure><p>In both cases, to seal the air volume between the box and the coupler, it is necessary to apply sealing material (blu-tack, putty) between the two parts. Since the dimensions are not the same as with the USound coupler adapter, some differences will emerge.&nbsp;</p><p><strong id="isPasted">Recommended reading:&nbsp;</strong><span style="background-color: transparent;"><a href="https://www.wevolver.com/article/why-usound-mems-speakers-outperform-electrodynamic-and-balanced-armature-micro-speakers" rel="noopener noreferrer" target="_blank">Why USound MEMS speakers outperform electrodynamic and balanced armature micro speakers</a></span></p><p>Nevertheless, the results will also be relevant to assess the MEMS speaker&rsquo;s performance. A comparison between the results obtained from the two methods mentioned above and the setup with USound&rsquo;s coupler adapter is shown in the following graph.</p><figure><img data-fr-image-pasted="true" src="https://www.usound.com/wp-content/uploads/2021/07/Achelous-UT-P2018-SPL-measurement-in-the-Carme-UJ-R1020.png" alt="Achelous UT-P2018 SPL measurement in the Carme UJ-R1020" srcset="https://www.usound.com/wp-content/uploads/2021/07/Achelous-UT-P2018-SPL-measurement-in-the-Carme-UJ-R1020.png 1003w, https://www.usound.com/wp-content/uploads/2021/07/Achelous-UT-P2018-SPL-measurement-in-the-Carme-UJ-R1020-300x124.png 300w, https://www.usound.com/wp-content/uploads/2021/07/Achelous-UT-P2018-SPL-measurement-in-the-Carme-UJ-R1020-768x316.png 768w" sizes="(max-width: 1003px) 100vw, 1003px" class="fr-fic fr-dii" style="height: 300px;"><figcaption>Achelous UT-P2018 SPL measurement in the Carme UJ-R1020 speaker-test box</figcaption></figure><p><br></p>