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AlixLabs AB of Lund, Sweden — which was spun off from Lund University in 2019 and has developed the Atomic Layer Etching (ALE) Pitch Splitting technology (APS) — is participating at SEMICON Japan 2024 at Tokyo Big Sight (11–13 December), marking the public debut for its 300mm wafer process chamber. Its Made in Sweden APS (ALE Pitch Splitting) tools are aimed at allowing the semiconductor industry to scale down to sub-7nm manufacturing processes in a more sustainable way, and is positioned as an alternative to costly double patterning or EUV (extreme ultraviolet) solutions...

Automotive technology firm Valeo and ROHM Semiconductor are collaborating by using their combined expertise in power electronics management to optimize next-generation power modules for electric motor inverters. As a first step, ROHM will provide its 2-in-1 silicon carbide (SiC) molded module TRCDRIVE pack to Valeo for future powertrain solutions...

Sheffield University spin-off Phlux Technology —which designs and manufactures 1550nm avalanche photodiode (APD) infrared sensors — has won an Institute of Physics (IOP) Business Start-Up Award 2024. Presented at the Houses of Parliament in London, the award celebrates young companies leveraging physics for innovation and impact. It recognized Phlux’s Aura family of Noiseless indium gallium arsenide (InGaAs) infrared (IR) sensors, which is said to have set new standards for sensitivity and performance in optical systems such as LiDAR, laser range finders, and optical fiber communications test equipment...

As a genre, DACs are low power devices with power and current output capabilities limited to the milliwatt and milliampere range. There is, of course, no fundamental reason they can’t be teamed up with suitable power output stages, which is indeed common practical practice. Problem solved.

Wow the engineering world with your unique design: Design Ideas Submission Guide

But just for fun, this design idea takes a different path to power by merging a venerable (the “L” stands for “legacy!”) LM337 regulator into a simple (just two generic active chips) 8-bit PWM DAC to obtain a robust 1.5-A capability. It also enjoys the inherent overload and thermal protection features of that time-proven Bob Pease masterpiece.

As an extra added zero cost feature, output voltage accuracy is (mostly: ~90%) determined by the + 2% (guaranteed, typically much better) precision of the LM337 internal voltage reference, rather than relying on the sometimes-dodgy stability of a logic supply rail as basic PWM DACs often do.

Figure 1 shows the circuit.

Figure 1 LM337 joins forces with 4053 CMOS switch to make a macho PWM DAC.

 Metal gate CMOS SPDT switches U1a and U1b accept a 10-kHz PWM 5v signal to generate a +1.25 V to -8.75 V “ADJ” control signal for the U2 regulator. ADJ = +1.25 V causes U2 to output 0 V. It has always struck me somehow strange that a negative regulator like the 337 sometimes needs a positive control signal (in this case for Vout less negative than -1.25 V), but it does. ADJ = -8.75 V makes it make -10 V. 

U1c generates an inverse of the PWM signal, providing active ripple cancellation as described in “Cancel PWM DAC ripple with analog subtraction.”

Current source Q1 reduces zero offset error by nulling the ~65 µA (typical) ADJ pin bias current. The feedback loop established via R2 and R3 makes full-scale -10 V output proportional to U2’s internal reference as previously mentioned.

This does, however, make output voltage a nonlinear function of PWM duty factor with functionality (DF from 0 to 1): Vout = -1.25 DF / (1 – 0.875 DF) as graphed in Figure 2.

 Figure 2 Graph of Vout (0 V to -10 V) versus the PWM duty factor (0 to 1).
[Vout = -1.25 DF / (1 – 0.875 DF)]

 Figure 3 plots the inverse of Figure 2, yielding the PWM DF required for a given Vout.

 Figure 3 Graph of the PWM duty factor (0 to 1) versus Vout (0 V to -10 V).
[PWM DF = Vout / (0.875*Vout – 1.25)]

For the corresponding 8-bit PWM setting Dbyte = 256 DF = 256 Vout / (0.875*Vout – 1.25).

The negative supply rail (V-) can be anything between -13 V (to accommodate U2’s minimum headroom requirement) and -15 V (in recognition of U1’s maximum voltage rating). DAC accuracy will be unaffected. 

U2 should be adequately heatsunk as dictated by heat dissipation equal to output current multiplied by the V- to Vout differential. Up to double-digit Watts are possible. The 337s go into thermal shutdown at junction temperatures above 150oC, so make sure it will pass the wet-forefinger-sizzle “spit test!”

Stephen Woodward’s relationship with EDN’s DI column goes back quite a long way. Over 100 submissions have been accepted since his first contribution back in 1974.

 Related Content

• Cancel PWM DAC ripple with analog subtraction
• Cancel PWM DAC ripple with analog subtraction—revisited
• Cancel PWM DAC ripple with analog subtraction but no inverter
• Cancel PWM DAC ripple and power supply noise
• Fast PWM DAC has no ripple
• Fast-settling synchronous-PWM-DAC filter has almost no ripple
• Minimizing passive PWM ripple filter output impedance: How low can you go?

The post 0 V to -10 V, 1.5 A LM337 PWM power DAC appeared first on EDN.

I wanted to share a reminder that you don’t need a dedicated workbench, shop, or even a large table to work on electronics projects. I don’t have the space or budget for a full setup, so I work at my desk while watching videos. However, constantly running back and forth to grab parts was frustrating and made setup and cleanup take forever. To solve this, I built a portable workbench that I can easily place on my desk or store on a shelf when not in use. Here’s what I did: I used glued wood planks cut to 40cm x 50cm. Made a small shelf for my soldering station by gluing wood scraps together, then secured it with screws. Added a hole at the back for the power supply, handles for easy carrying, and rubber feet to keep it stable on any surface. Screwed my soldering equipment onto the board so everything stays in place. Now, I can set up and start working in seconds, and so far, it’s been a game-changer! front view top view shelf view submitted by /u/Alfagun74 [link] [comments]

I came across a DIY power supply using a DPS5005 Switching Power Supply and decided to give it a go. I'm pretty happy with the housing as that's pretty much all this project is but I still like it. I did however skip the use of a USB C PD board and just use a random 48v supply. I also added more ferrets to the output to try and clean up the switched power. submitted by /u/iamnotatigwelder [link] [comments]

Infineon has announced FreeRTOS support for its 32-bit AURIX TC3x family of automotive and industrial microcontrollers. As a key software layer, the RTOS manages both hardware and software resources, ensuring reliable and timely task execution. Acting as a bridge between the hardware and application software, it simplifies development by abstracting hardware complexities. This approach enhances portability and code reusability, streamlining the development process and reducing time-to-market.

FreeRTOS is a widely used, open-source real-time operating system actively supported and developed by Amazon Web Services (AWS). AWS also offers middleware libraries for FreeRTOS, enabling seamless integration with its cloud services.

“The availability of FreeRTOS enables customers to rapidly build applications on a well-established and feature-rich open-source environment,” said Patrick Will, head of Software Product Management and Marketing for Automotive Microcontrollers at Infineon. “This integration facilitates quick feature evaluation on the AURIX TC3x and provides our customers with an accelerated migration path for non-AUTOSAR projects, particularly in the automotive and industrial markets.”

TriCore AURIX TC3x MCUs offer ASIL-D/SIL-3 compliance and advanced safety features, as well as scalable feature sets and pinouts. The FreeRTOS kernel port for the AURIX TC3x is available here. Corresponding code samples can be found here.

AURIX TC3x product page

Infineon Technologies 

Find more datasheets on products like this one at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

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MIFARE DOUX, NXP’s contactless near-field communication (NFC) chip, integrates asymmetric and symmetric cryptography in one IC to simplify key management and distribution. The smart card IC enhances security for EV charging authentication, vehicle access, and other access management applications.

Leveraging public-key infrastructure (PKI), the chip supports asymmetric elliptic curve cryptography (ECC) and symmetric AES-256 cryptography. Additional features include a proximity check to counter relay attacks and transaction signatures to validate NFC transaction authenticity.

MIFARE DUOX holds Common Criteria EAL 6+ certification for both hardware and software, making it well-suited for high-security applications. Built for demanding environments, including outdoor and automotive use, it complies with ISO/SAE 21434 and MISRA-C standards and operates across an extended temperature range of -40°C to +105°C.

The MIFARE DUOX contactless smart card IC is now available.

MIFARE DUOX product page

NXP Semiconductors 

Find more datasheets on products like this one at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

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The u-blox SARA-R10001DE LTE Cat 1bis module integrates Wireless Logic’s Conexa embedded SIM (eSIM) for global IoT connectivity. Supporting multi-IMSI technology and eUICC, the eSIM streamlines connectivity management by enabling automatic network switching based on coverage, cost, and regulatory needs.

The SARA-R10001DE supports full LTE Cat 1bis band coverage and comes provisioned with multiple Wireless Logic SIM profiles, permitting global deployment with a single SKU. In addition to working seamlessly upon deployment, the eSIM can also be remotely configured through Remote SIM Provisioning (RSP). It also enhances resilience by automatically switching to the best network available to ensure uninterrupted service in diverse regions.

Designed for LTE global coverage, the single-mode SARA-R10001DE provides a straightforward upgrade path for replacing legacy 2G and 3G devices with 4G LTE technology. The 16×26×2.2-mm module includes UART, USB, and GPIO interfaces and operates over a temperature range of -40°C to +85°C.

SARA-R10001DE product page 

u-blox

Find more datasheets on products like this one at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

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Identiv’s high-frequency NFC-enabled inlays leverage NXP’s ICODE 3 tag IC, boosting RF performance and read speed. Designed for IoT applications, the ICODE 3 chip includes features suited for healthcare, logistics, industrial use, smart packaging, and specialty retail.

Identiv’s 13.56-MHz ID-Tune I3 and ID-Safe I3 inlays support both vicinity-range operation, reaching up to 1.5 meters, and close-range interactions. In vicinity mode, improved readability, material compatibility, and fast data transfer ensure seamless integration and increase operational efficiency. For close-range use, features such as first-opening indication and flexible counters enhance user engagement and product interactivity.

Key features of the ICODE 3-based inlays include:

• ISO/IEC 15693 and NFC Forum Type 5 tag compliance
• Read rate of up to 212 kbps
• One-lock memory command for tag encoding
• Customizable originality signature of 32 or 48 bytes
• Automatic SELFAdjust mechanism optimizes RF performance across different materials and conditions
• Two password-protected untraceable modes
• Extended NFC features for serialized, dynamic, and contextual messaging when tapped with an NFC-enabled phone

For more information about the ID-Tune I3 and the ID-Safe I3, which includes tamper detection, click on the product page links below.

ID-Tune I3 product page

ID-Safe I3 product page 

Identiv

Find more datasheets on products like this one at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

The post NFC inlays are powered by NXP’s ICODE 3 appeared first on EDN.

PROFET Wire Guard high-side switches from Infineon provide built-in I2t wire protection for 12-V automotive power distribution. According to the manufacturer, these devices more accurately emulate wire stress characteristics compared to conventional fuses by using a selectable I2t protection curve, with six options tailored to specific application requirements.

In addition to I2t protection, the switches offer adjustable overcurrent protection for fast fault isolation and sequential diagnostics, enabling wire harness optimization when replacing mechanical relays and fuses. PROFET Wire Guard smart switches handle currents up to 27 A and a maximum operating voltage of 28 V. A low-power automatic idle mode reduces current consumption to just 50 µA during vehicle parking, while the output stage remains fully switched on.

The five PROFET Wire Guard devices offer pin-to-pin compatibility within the family and come in TSDSO-14 and TSDSO-24 packages. They have been developed and released as ISO 26262:2018 Safety Elements Out of Context (SEooC) for safety requirements up to ASIL D

PROFET Wire Guard product page

Infineon Technologies 

Find more datasheets on products like this one at Datasheets.com, searchable by category, part #, description, manufacturer, and more.

The post High-side switches offer integrated wire protection appeared first on EDN.

POET Technologies Inc of Toronto, Ontario, Canada — designer and developer of the POET Optical Interposer, photonic integrated circuits (PICs) and light sources for the data-center, telecom and artificial intelligence (AI) markets — is to expand its optical engine production capacity in Malaysia...

Wolfspeed Inc of Durham, NC, USA — which makes silicon carbide (SiC) materials and power semiconductor devices — has appointed Melissa Garrett as senior VP & general counsel, effective 9 December. She succeeds Brad Kohn, who has resigned from the firm for another professional opportunity..

submitted by /u/1Davide [link] [comments]

Further to my prior coverage of this year’s iteration of periodic lightning-damage debacles at my Rocky Mountain foothills residence, I’d earlier mentioned that among the pieces of electronics gear that bit the dust this time was one of my network storage devices (NASs). The setback compelled me to no longer ignore a longstanding chink in my data-backup armor, which I’ve subsequently patched. What it was, and how I fixed it, is the subject of today’s post.

Simplistically speaking, there are (at least) three main ways that a storage device’s data can become compromised:

• If a virus, ransomware or other malware corrupts it, either via a computer it’s directly connected to, another device on the LAN, or a WAN-sourced attack, scenarios for which QNAP offers regularly executed (and updated) integrated scan-and-alert support.
• If a hard drive (or SSD, in some cases) fails. That’s why at minimum my NASs are all dual-drive setups, enabling RAID 1 redundancy, and they preferably contain at least three drives to add RAID 5-delivered performance to the mix, too.
• If the storage device itself dies; the power supply, for example, or something on the motherboard. Sometimes the failing component is straightforward to replace, but other times the NAS is destined only for the teardown pile, followed by the landfill.

The latter situation is the one I encountered recently. As background, I had two NASs active on my network at the time. My four-drive QNAP TS-453Be holds my music and photo libraries, along with decades’ worth of other accumulated personal files:

Its sibling beside it, a three-drive TS-328:

is my network backup destination. Part of the available capacity acts as a Time Machine repository for my Macs, while the remainder handles our various Windows machines, via a combo of File History and the legacy (and deprecated, but still included) Backup and Restore, both of which I’ll likely replace with something third-party and more modern sooner vs later.

The TS-328 is the one that died earlier this year. Although I could still get it to emit a factory-reset “beep”, firmware recovery attempts were fruitless; I’m guessing something(s) vital on the motherboard had fried (a common issue with this model, not just in response to an external “zap”, so I already knew I was running on borrowed time). While its stored data was less critical than that on the TS-453Be, since thankfully none of the computers previously backing up to it had themselves also failed, I wanted to get backup back up (heh heh) and running as quickly and straightforwardly as possible. And clearly, had the TS-453Be failed instead (or in addition), I would have had a more acute situation on my hands.

Step one: resurrect the TS-328. I found a gently used one on eBay (for nearly $100 more than I’d paid for my brand new one five-plus years earlier, although the seller did also throw in a used eight-port GbE switch, but I digress…), which was shipped and arrived promptly. I pulled the HDDs out of the original TS-328 and reinstalled them in the new-to-me NAS in the same order as before. And then I crossed my fingers and punched the power button.

Huzzah; it booted! Since the replacement NAS had only recently been retired by its previous owner, I’d gambled that its firmware version was close-to-identical to that in my expired device, which ended up being the case. There was only a minor discrepancy between the new-to-me NAS’s motherboard firmware version and the newer version stored on my old NAS’s drives, which I was alerted to and an online-supplied firmware update remedied. And speaking of online, I was glad to see that QNAP’s cloud service was smart enough to notice that the device now mated to my HDDs, therefore to my online account, had different hardware than was previously the case (a new MAC address at minimum) and insisted that I re-login and -associate the NAS with it first.

Now to fix my setup’s “chink in the armor” resulting from full-NAS failure potential. Some of you may already be familiar with the “3-2-1 backup rule”; Wikipedia has a concise summary:

The 3-2-1 rule…states that there should be at least 3 copies of the data, stored on 2 different types of storage media, and one copy should be kept offsite, in a remote location (this can include cloud storage). 2 or more different media should be used to eliminate data loss due to similar reasons (for example, optical discs may tolerate being underwater while LTO tapes may not, and SSDs cannot fail due to head crashes or damaged spindle motors since they do not have any moving parts, unlike hard drives). An offsite copy protects against fire, theft of physical media (such as tapes or discs) and natural disasters like floods and earthquakes.

While, as you’ll see in the paragraphs to follow, I’m not following the 3-2-1 rule to the most scrupulous degree—all of my storage devices are HDD-based, for example, and true offside storage would be bandwidth-usage prohibitive with conventional home broadband service—I feel, and hope you’ll agree, that I’ve followed it sufficiently, and that regardless the result is much more robust than it was before. It involves among other things pressing into service the two-drive QNAP TS-231K NAS that I’d also mentioned back in December 2020. I bought three (including a spare) 12 TByte used Hitachi enterprise SATA HDDs with five-year warranties for it from a well-known eBay retailer. Two of the three drives arrived reporting S.M.A.R.T warnings (197+198 sector count code combos, to be precise), but to the retailer’s credit, it replaced them promptly, even proactively sending replacements ahead of the originals’ return.

For my Macs, on which the “primary copy” of the data is stored, implementing the 3-2-1 rule was particularly straightforward. Modern MacOS versions support Time Machine configuration for multiple destinations, which the utility rotates among automatically for consecutive backups. While this means that each backup likely ends up being bigger (i.e., taking longer) than before, given that the precursor backup to that same destination was older than with a conventional single-destination alternative setup, it also means that if one destination fails, you’ve still got relatively current backups available at alternate destinations. In my case, there are two backup destinations, the Time Machine-tailored partitions on the TS-231K and TS-324. And counting the Mac source, you end up with three dataset copies total, if you’re not already keeping track.

What about the Windows systems? Again, the “primary copy” of the data is located on their SSDs. I run Backup and Restore sessions from them to the TS-324 every early-Saturday morning (since they tend to swamp Wi-Fi while in progress). And every early-Sunday morning, the QNAP HBS 3 Hybrid Backup Sync utility then does a full mirror of the archived Windows backup data from the TS-324 to the TS-231K (over Cat 5 this time, but still, why not do this while we’re still asleep?). This time, if one NAS fails, the backup data on the other NAS is no more than a week old. And once again, I end up with three total dataset copies.

The TS-453Be is a bit more complicated. Here, the primary copy of the data is stored on its four-HDD RAID 5 array. I’ve long had an external 2.5” HDD USB-tethered to it for daily sync purposes, which I can quickly grab (theoretically, at least) in case of fire or another emergency. And now, once again on Sunday mornings, the TS-453Be also does a full mirror to the TS-231K.

“Quickly grab” leads to my final discussion topic, involving the different-locations angle on the 3-2-1 rule. As I’ve already confessed, none of my backups are located offsite. However, I’ve installed the TS-231K upstairs in my office (at least for now, until I lose my sanity due to the constantly-clattering-HDDs din), still connected to the router over wired GbE, albeit now with a two-switch hop intermediary, as well as to the two other NASs and other LAN devices. And, as with the TS-324, the TS-453Be manages controlled shutdown of the TS-321K in response to premises power loss in coordination with their common NUT software and my APC UPS.

As I’ve mentioned before, the furnace room downstairs acts as my networking nexus. The probability for fire caused by the one of the furnaces (or any of the other equipment, for that matter) in that room is non-zero, and since that “other equipment” includes the hot water heater, fluid-delivered compromise of the NASs there is also a possibility. And given that “downstairs” is also “ground level”, an outside-sourced fire is also an ongoing concern, one accelerated of late due to climate change-induced environmental effects. But, thinking as I write these words, since my office is directly above the furnace room…yeah, having the TS-231K in my office probably isn’t wise, noise-wise or otherwise. Time to figure out somewhere else to put it.

With that, I’ll wrap up for today and welcome your thoughts in the comments!

—Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.

Related Content

• Lightning strikes…thrice???!!!
• The whole-house LAN: Achilles-heel alternatives, tradeoffs, and plans
• NAS successors add notable features
• Disassembling a Cloud-compromised NAS
• Exposing a NAS security issue
• NAS failure launches a data recovery mission
• Teardown: Disposable 1-Tbyte NAS drives: How’d that happen?

The post Beefing up backup appeared first on EDN.

Передові виробництва співпрацюють з КПІ. КЗ ПТО kpi пн, 11/25/2024 - 20:29

КПІ ім. Ігоря Сікорського на масштабній міжнародній конференції IREG 2024 "Artifficial Intelligence (AI) altering Higher Education and Rankings" kpi пн, 11/25/2024 - 19:00

Usually, noise annoys. Occasionally, it can be a valuable tool. Surprisingly, there is a whole palette of noise colors. This design idea (DI) shows good ways of generating the commonest and most useful ones, which are white and pink and optionally brown. At its heart is a microcontroller programmed to generate raw white noise and a much-improved filter to convert that into pink.

Wow the engineering world with your unique design: Design Ideas Submission Guide

Sources of random electronic noise are all too common. The most controllable source of the white stuff is probably the well-known pseudo-random binary sequence (PBRS) generated by a shift register with feedback, and that will be our starting-point. A fairly standard implementation using logic ICs is shown in Figure 1.

Figure 1 A pseudo-random sequence generator (PRSG) built with standard logic ICs generates wideband white noise.

Three 8-bit devices (or dual 4-bit ones, as here) are concatenated to make a 23-bit shift register. The outputs from bits 18 and 23 are EXORed and inverted (or EXNORed) and fed back to the input, producing a pattern of bits which appears random though it repeats every 223-1 clock cycles, which at a clock rate of 240 kHz is about every 35 seconds. (That “-1” represents the illegal, locked-up, all-1s condition, against which the simple reset circuitry guards.) For frequencies up to about a tenth of the clock rate, the spectrum is virtually identical to that of pure and ideal white noise. It has the same intensity in any given bandwidth: its spectrum is flat. For other colors, we just need to filter it appropriately.

A cheap microcontroller makes a good PRSG

So far, so conventional. But why use 62-pins-worth of chippery plus at least ten discretes when a single package with 8 pins—or even fewer—will suffice? The schematic for that is too boring to show—imagine a rectangle fed with power (decoupled with a single cap) and having a GPIO pin delivering the PRBS—but here is the MPASM assembly-language code for doing it with on a Microchip 12F1501 PIC. (It should open cleanly with Notepad.) The code is logically and functionally identical to Figure 1’s circuit and can easily be modified for use in different low-end PICs, while the underlying logic can be ported to any other suitable µC. (Back in the day, NatSemi made the MM5837, an 8-pin, 15-V, PMOS white noise source using 17 stages. It’s long obsolete, but this could be a nice substitute for it.)

We now have pseudo-random white noise with a spectrum ranging roughly from 30 mHz to a few MHz, which is just a few more octaves than we need. (There are nulls at multiples of the bit rate, which is 267 kHz for this PIC version.) It’s still in the form of a pulse stream, which needs band-limiting before we have truly useful white noise. For pink noise, further filtering is needed so that all octaves (or other frequency ratios) have the same intensity, which is what we need for audio use. The circuitry to do all this is shown in Figure 2.

Figure 2 A pseudo-random signal—white noise—is tailored to fit within the audio band, and further filtered to produce pink noise as well.

The PRSG could use Figure 1’s discrete logic, but the micro version is electrically quieter (hah!) as well as being more compact and, ignoring programming overheads, cheaper. The pulse-shaping network turns the rail-to-rail rectangular pulse stream into trapezoids having a defined level (about 1.2 V pk-pk) and with slew rates less than those of the downstream op-amps. The 20 kHz low-pass filter does what it says. (That “20 kHz” isn’t its 3-dB corner, but a label for its function.) Only high-pass filtering from ~20 Hz is now needed to give white noise within the audio spectrum and at a level of just greater than -10 dBu.

A new and improved pink noise network

Pink noise is a little trickier and needs a more complex filter to give the necessary 3.01 dB/octave (10 dB/decade) slope. Most published solutions use four RC sections as well as the basic R and C shown in Figure 2 as R10 and C11, with some having even fewer. (And many appear to be clones.) Those RCs have their component values spaced by around √10, but some thought and playing with LTspice showed that far better results come from using a few more stages, and ratios close to the cube root of 10. Figure 3 shows the calculated response of Figure 2’s seven-stage network without the added high- or low-pass filters. Even with E12 component values, it is almost a straight line, unlike the clones’ responses.

Figure 3 The response of the new 7-stage pink noise filter, taken in isolation.

A gain stage brings the pink noise’s RMS level up to -10 dBu to match that of the white, while a selection switch, level-control pot, output buffer, and rail-splitter (A2d etc.) complete the design. Figure 4 shows the calculated response curves along with the worst-case deviations from ideal.

Figure 4 The calculated responses of the completed design, showing the mask for IEC 60268-1 limits and the peak errors of the filters.

The output is now within ±0.2 dB of the ideal from 24 Hz to 21 kHz. With slightly softer HP and LP filters even that could be improved on, especially by reducing the ripple at the ends of the spectrum, but they were calculated to meet the requirements of IEC 60268-1, which refers to the performance, testing, and application of audio systems.

Some further notes on the circuitry

Figure 2’s circuit was designed (and tested) to use a nominal 5 V (or ±2.5 V) rail (what are cheap power banks or surplus USB PSUs for?) but the extremes of 2.7 V (three end-of-life AA cells) and 5.5 V (USB limit) allow for other powering options.

The shaping network ensures that the output will be reasonably constant no matter what the rail voltage may be, and the signal levels of -10 dBu avert clipping even for low rail voltages. With a guaranteed 5 V supply, A2c could have about 7 dBs of extra gain before clipping starts. The output crest factor—the peak-to-RMS ratio—is fairly high, at around 5:1 or 14 dB.

A1a uses the MCP6022 rather than the MCP6004 (or MCP6002s, of course) because the latter can only just cope with the shaped pulses and distorts them noticeably. The gain needed after the pink noise network is rather high, so A1b is also a ’6022: faster, and with lower input offset. The ’6004 works fine in all the other positions. The components between A2c and the output aren’t mandatory, just good practice.

Current consumption was about 6 mA, unloaded.

Brown(ian) noise generation

Adding brown—or red, or Brownian—noise generation is simple, as sketched in Figure 5. All that’s needed is an RC network, giving a 6.02 dB/octave (20 dB/decade) fall-off with increasing frequency, followed by lots of gain. (Some sources specify two cascaded 3 dB/octave—pink—networks, but surely that’s more expensive and less accurate?) The values shown give a -10 dBu output (~2.6 V pk-pk) to match the other responses. Obviously, the switching shown in Figure 2 needs to be changed if you want to add this. For use in isolation, precede it with at least the 20 Hz high-pass filter, or your woofers may try to simulate a small earthquake.

Figure 5 This simple circuit converts white noise into Brownian.

Implementing other pseudo-random sequence lengths

The PIC- (or other µC-)based PRSG may have other uses needing different sequence lengths. It’s trivially easy to change the code as long as only two taps from the (virtual) shift register are needed; more taps would need more XNOR code. This reference has a comprehensive table showing the necessary taps as well as a lot of useful background information.

Longer sequences just need extra registers, with each one adding a single processor cycle; the XNOR logic takes longer to run (12 cycles) than the shifting. Eight concatenated registers with feedback from bits 62 and 63 would give a sequence that only repeats after some 1.2 million years, assuming a clock rate of 16 MHz (4 MHz instruction rate). Using 10 registers, tapped at bits 70 and 79, ups that to around 77 billion years. Long enough? If not, the above reference gives many 2-tap solutions for up to 167 bits. You might then want to invest in some ultra-ultra-long-life batteries or a really, really reliable UPS.

—Nick Cornford built his first crystal set at 10, and since then has designed professional audio equipment, many datacomm products, and technical security kit. He has at last retired. Mostly. Sort of.

 Related Content

• Ultra-low distortion oscillator, part 2: the real deal
• Squashed triangles: sines, but with teeth?
• 1/f Noise—the flickering candle
• Create noise and signals with software
• The pink noise tangent principle

The post Earplugs ready? Let’s make some noise! appeared first on EDN.

КПІ ім. Ігоря Сікорського серед лідерів України у рейтингу THE Interdisciplinary Science Rankings 2025 kpi пн, 11/25/2024 - 12:48

Fiber optic cables play a key role in high-speed network expansion. As wireless and cellular network complexity increases, fiber networks supporting elevated bandwidth, latency and data transmission rate demand have become essential. How should electronics design engineers incorporate this technology into their projects?

It’s important to note that that fiber network cables that were once considered cutting-edge have become legacy technology sooner than professionals could have anticipated. Even fiber has undergone significant changes since its inception, boasting advancements like fusion splicing and single-mode cables.

With advancement comes expansion. In August 2024, the Federal Communications Commission (FCC) announced it would move forward with targeted investments in fifth generation (5G) wireless cellular technology, distributing around $9 billion to facilitate 5G-capable networks. This plan will require massive, high-density fiber infrastructure.

Traditionally, mobile backhaul networks used copper time division multiplexing (TDM) circuits, which have become a legacy technology. Fiber cables are one of the only alternatives that make sense for longevity. However, while fiber deployment guarantees lasting improvements, engineers must still make proactive design decisions to ensure a lifetime of use from the upgrades.

How fiber cables fit into modern infrastructure

The rapid proliferation of advanced wireless and cellular network infrastructure has outpaced the capabilities of supporting components. Fiber cables are the clear alternative because they offer benefits like space efficiency, superior bandwidth, higher data transmission rates, and long-distance signal integrity.

Already, the United States has made progress toward a fiber-based future to support rapidly proliferating high-speed networks. As of December 2023, 60.4% of fixed connections in the country were coaxial cable, while 23.1% were fiber optic. Copper wire, fixed wireless, and satellite made up the remaining percentage.

Although the fiber adoption rate will inevitably increase, laying the groundwork for advancement is no longer enough; electronics design engineers must future-proof modern infrastructure. They can keep computing resource demand from outpacing infrastructure capabilities within the coming decades.

Designing high-speed networks with fiber

Electronics design engineers should first consider which type of fiber cable will suit their needs well into the future. While the larger 62.5-micron core of multimode cables enables higher data transmission rates, its range is limited. Single mode may be more expensive upfront, but it helps facilitate a more expansive network.

Strand count is another important consideration. While surpassing the project’s minimum requirements may seem unnecessarily expensive, it helps future-proof the infrastructure. Engineers should consider how factors like urbanization and wireless cellular technology will affect their design’s efficacy over the coming decades.

Of course, deploying fiber requires time, resources, and money. The median cost of underground deployment is $16.25 per foot, while the median aerial cost is around $6.49 per foot. Labor accounts for 50% to 90% of the total cost. Professionals should conduct a feasibility study—considering possible routes and the practicality of expansion—to determine which designs and areas to prioritize.

Will government policies affect electronic component availability? Will business leaders be able to secure research and development grants? Future-proofing wireless and cellular networks involves considering every possibility. However, electronics design engineers must be careful not to overcomplicate planning.

Ellie Gabel is a freelance writer as well as an associate editor at Revolutionized.

 

 

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