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I've been wanting to make a card that has the usually hidden SMBus and JTAG signals in a PCIe slot available to the user. I've also made 3.3V, 5V and 12V rails available. If you want to checkout the project go checkout the github. submitted by /u/SuperCookieGaming [link] [comments]

I wanted to put together a minimal LED flasher circuit using only a few components. No microcontrollers, no 555 timer, just good old analog behavior. Parts used: 1 × BC547 transistor 1 × 1000µF capacitor 1 × 1k resistor 1 × LED How it works: The capacitor charges slowly through the resistor. Once it hits a threshold voltage, the transistor conducts and lights the LED briefly. Then the cap discharges and the process repeats, it creates a satisfying blink loop. It starts flashing after a short delay and just keeps going. I’d love to hear ideas on how to iterate on this, different values, transistor types, or ways to expand it? I posted a short 30s demo in the top comment if you'd like to see it in action. submitted by /u/ftuncer59 [link] [comments]

Behind the foundational and advanced radar textbooks of our day stood the brilliant engineer and researcher Merrill Skolnik.

My first proper audio setup, discounting the GE Wildcat record player I had as a kid:

was a JVC PC-11 portable stereo system (thank goodness for Google Image Search to refresh my memory!), an example of which my (Catholic) high school chaplain owned, played (George Winston tapes, to be precise) in the background during weekly confession sessions, and acted as inspiration for my own subsequent acquisition, which made it through most of college:

Pretty slick setup: this was the pre-CD era, but the JVC PC-11 included an AM/FM tuner, five-band equalizer, cassette player, all (plus the speakers) detachable, and turntable inputs:

And for the purposes of today’s discussion, check out these modest specs:

• Output power: 2 x 15 W max.
  • DC fluctuation: < 0.05 % WRMS
• Speaker chassis diameter: 120 mm “High Ceramic” cone
  • Impedance: 6 Ohm
  • Efficiency: 90 dB / W / m

Nevertheless, it could fill my dorm-later-fraternity room with tunes discernible even over whatever party might have been going on at the time. Distorted? Mebbe. But discernible still.

Historical precedents

Even more “proper” was a Kenwood KA-4002 integrated amplifier (albeit with switch-selectable separate preamp outputs and main amp inputs, plus a separate mono output, no less!), apparently manufactured from 1970-1973, that I acquired at around that same time. I vaguely recall that my dad might have bought it for me used from a co-worker of his? The JVC PC-11 eventually died: I vaguely recall—again—that the cassette deck locked up, plus the pressboard-construction speaker enclosures were getting beat up from my back-and-forth moves between the university campus in West Lafayette and my co-op sessions at Magnavox in Fort Wayne.

At that point, I pressed the KA-4002 into service, along with speakers and other discretes whose identities I no longer recall (though I remember a 10-band equalizer with a bouncing red multi-LED display!). It eventually also met its demise, complete with an acrid “magic smoke” release if I recall correctly, but only after serving me faithfully for a remarkably long time, including, at the end, acting as a power amplifier for a passive subwoofer. Again, check out the modest specs:

• Continuous power (at THD)
  • 8 Ohm: 2×18 W (RMS, 20Hz…20Khz, 0.05% THD), 2x 24W (8 Ohm, 1Khz)
  • 4 Ohm: 2×33 W

A modern (and even more modest) successor

I reminisced about both of these past personal case studies when I saw on Reddit last November that audio equipment manufacturer Schiit (who I’ve mentioned before) was doing a $99 (vs $149 MSRP) last-call sellout of its Rekkr 2W/channel amplifier. The Rekkr product page is no longer live on the manufacturer’s website, but here’s a January 2, 2025, snapshot courtesy of the Internet Archive. Stock photos (still active on Schiit’s web server as I type this) to start:

Yes, it really is that small:

and came in both black and—briefly—silver patina options:

Now for a peek at the internals:

For those of you still scratching your head at that earlier 2W/channel power output spec, allow me to reassure you that it’s not a typo. More precisely:

• Stereo, 8 Ohms: 2W RMS per channel
• Stereo, 4 Ohms: 3W RMS per channel
• Mono, 8 Ohms: 4W RMS

That last one’s particularly interesting to me; hold that thought. For now, here’s a visual hint:

More:

• Frequency Response: 20Hz-20KHz, ±0.01dB, 3Hz-500KHz, ±3dB
• THD: <0.001%, 20Hz-20KHz, at 1V RMS into 8 ohms 
• IMD: <0.001%, CCIR, at 1V RMS into 8 ohms
• SNR: >120dB, A-weighted, referenced to full output 
• Damping Factor: >100 into 8 ohms, 20-20kHz
• Gain: 4 (12dB)
• Input Sensitivity: AKA Rated Output (Vrms)/Rated Gain. Or, 4/4. You do the math.
• Input Impedance: 20k ohms SE
• Crosstalk: >80dB, 20-20kHz
• Inputs: L/R RCA jacks for stereo input, switch for mono input on R jack
• Topology: fully discrete, fully complementary current feedback, no capacitors in the signal path
• Oversight: over-current and over-temperature sensors with relay shutdown for faults
• Power Supply: 6VAC, 2A wall-wart, 12,000µF filter capacitance, plus boosted, regulated supply to input, voltage gain, and driver stages
• Power Consumption: 12W maximum 
• Size: 5” x 3.5” x 1.25”
• Weight: 1 lbs.

And here’s a link to the Audio Precision APx report PDF (also still active as I write these words; if not by the time you read them, you can get to it from the Internet Archive product page cache).

Target usage details

How on earth did Schiit rationalize the development and (even more notably) subsequent productization of such a seemingly underpowered product? Here’s the intro to company co-founder (and chief analog design engineer) Jason Stoddard’s “Less Power, More Better” post at the Head-fi forum, which accompanied the public unveil of Rekkr (and its Gjallarhorn “big brother”, which is still in the product line) on February 23, 2023:

And so now there’s Gjallarhorn and Rekkr, and a whole bunch of people saying, “I don’t care I can get a Class D widget with like 100,000 watts that’s the size of a matchbook for $4, why are you making these crazy low-power antique-technology things?”

Let’s start with the TL;DR:

• Because they don’t hiss like a demon cat, drilling slowly into your synapses and draining your soul.
• Because let’s face it, how much power do you need for desktop speakers?
• Because, reaaaaaally let’s face it, how do your neighbors feel about 100,000 watts if you share walls with them?
• Because these little suckers probably get a lot louder than you think.
• Because they sound really, really good.

In short: less powah. Moar better.

A new idea, yes. But maybe one you can get behind.

These next few paragraphs from his post were especially resonant for me, as you’ll understand now that I’ve shared my own personal low-power audio amplifier heritage with you:

A Billion Years Ago…I had a compact Realistic receiver that did 10 watts per channel into 8 ohms. Together with some tiny Minimus-7 speakers, it sounded pretty darn good. And it got fairly stupidly loud, enough that my parents really regretted me getting into music.

Think about that a bit: 10 watts into 4” 2-way speakers that were probably, what, 85dB efficient at best (in other words, they don’t make much sound for the watts you put in). Bass cranked almost all the way up…loud enough to piss off your shared-wall neighbors…that 10 watts did fine.

Somehow this antique receiver and speakers burrowed its way into the back of my mind and sat there for, like, 40 years. Because I always enjoyed the way it sounded. And I tried to replicate the experience over and over again.

I commend the full post to your attention, but for now, I’ll dive into detail on a few of Jason’s overview points. First off, what did he mean by “Because they don’t hiss like a demon cat, drilling slowly into your synapses and draining your soul”? He was contrasting Rekkr’s Class AB approach to what alternative noisier (he believed, at least, and at least at the time) Class D amplifiers exhibit. My personal take: he might have been right about Class D a few years ago, especially in the near-field configurations he’s specifically advocating for Rekkr, but no longer. More on that in a follow-up post to come.

Usage requirements

Speaking of near-field, let’s attempt to quantify his comment, “Because let’s face it, how much power do you need for desktop speakers?” Near-field translates to (among other things) “close proximity”, i.e., speakers located 5 feet (1.5 meters) or less away from the listener. Why’s this important? It’s because sound intensity follows the inverse square law: doubling the distance from a sound source reduces the intensity to one-quarter of its original value (said another way: the sound level will be down by 6 dB). There’s a handy online calculator (along with others) for ascertaining sound level variance versus distance on Crown Audio’s System Design Tools webpage. And to my earlier comments: near-field speaker configurations are conveniently-for-Jason also most likely to result in listener-discernible amplifier-generated “hiss”.

Directly above that calculator is another one we’re going to focus on most today, titled “Amplifier Power Required”. Note that sound level is a function of multiple factors:

• Distance (already discussed)
• Speaker sensitivity, which indicates how efficiently a speaker converts electrical power into sound. It’s measured in decibels at a specific distance (usually 1 meter) from the speaker when 1 watt of power is applied. The higher the sensitivity (which for any single- or multi-transducer setup also varies with frequency; the spec’d value is an average), the louder it will sound for a particular connected-amplifier power output. Or said, another way, the higher the sensitivity the less power is needed to hit a given sound level.
• And, of course, the amplifier’s per-channel power output capability (optionally also allowing for headroom to prevent clipping caused by sound level “peaking”). This is in part dependent on the speaker impedance load that the amplifier is connected to (lower impedance = higher output power). Reference, for example, the earlier Rekker specs.

Crown Audio’s “How Much Amplifier Power Do I Need?” essay provides an excellent review of these factors, along with their relevance to different kinds of music and listening environments. I’ll only offer one caution: the company’s business model particularly focuses on live sound venue setups, so although the essay concepts remain relevant for the home, you’ll need to tweak the specifics a bit. For now, let’s plug the following values into the online calculator:

• Distance: 1.5 meters
• Desired sound level: 85 dBSPL
• Speaker sensitivity: 85 dB (at 8 ohms)
• Headroom: 3 dB

The calculated result? The required per-channel amplifier power is only 4W (per channel for a stereo setup). Decrease the speaker-to-listener distance, and/or the peak sound level (and/or associated headroom), and/or increase the speaker sensitivity, and the per-channel amplifier power requirements further plummet.

To wit, trust me when I tell you that I didn’t proactively twiddle with the input values to come up with any particular calculator output end result. In fact, they actually overshoot those of the setup I’m planning on hooking up shortly after completing this preparatory write-up. It’s based on a set of Audioengine P4 passive speakers:

rated at 88-dB sensitivity and 4-ohm nominal impedance. Their likely normal distance to me will be more like 3 feet, not 5 feet, i.e., 1.5 meters (but we’ll stick with 5 feet for now). And when Jason postulates about how “neighbors feel about 100,000 watts if you share walls with them”, in my case, that’s my wife, who I doubt will long tolerate 85 dB (or even close) sound levels spreading from my office throughout the rest of the house. That said, try this data set:

• Distance: 1.5 meters
• Desired sound level: 85 dBSPL
• Speaker sensitivity: 88 dB (at 4 ohms)
• Headroom: 3 dB

And you’ll discover that the result, 2W/channel, is less than the 3W/channel (4 ohm) output power capabilities of a single Rekkr. To confirm or deny the calculator claim, I’m going to try out this single-amp configuration first. And then, since I happen to have a pair (two pairs, actually, both black and silver sets) and it’s so easy to configure them in monoblock mode (the user manual is here on Schiit’s site, for all the implementation details), I’ll try ‘em that way, too. Stand by for results to come in a follow-up post (or a few) soon.

Is bigger always better?

As is often the case with my writeups, my motivation here wasn’t just to tell you about a diminutive audio amplifier that seemingly punches above its weight. And it also wasn’t just to quantify for you that, in fact, at least for its target usage scenarios, Rekkr’s weight was exactly right. It was to use this case study as an example of a bigger-picture situation: that in the absence of in-depth understanding to the contrary, consumers are always going to assume that “bigger numbers are always better”…even if those bigger (power output, in this case) numbers come with bigger price tags, and/or require housing product in bigger (and heavier) form factors, and/or have bigger associated distortion specs, and/or…you get my drift.

I strongly suspect that many of you, whether you’re in the audio industry or another, regularly struggle with “crazy numbers-for-sake-of-numbers, power-nervosa specsmanship” (see below for the verbiage reference) demands from your target customers and/or your own company’s marketing, sales, corporate execs and others, often motivated by your competitors’ statements and new-product actions. I’d love to hear more about the specifics of your various situations and how you deal with them. Please sound off with your thoughts in the comments; your fellow readers and I look forward to reading and responding to them. Thank you in advance!

Jason delves into this understandably frustrating dichotomy at the tail-end of his February 2023 post, which I’ll reproduce in full in closing, preceded by the reality-check calibrating contents of a subsequent post he made last November when word of the Rekkr discontinuation became known to the community: “Rule 1 of all business: don’t make what people don’t buy.”

The “less power, more better” manifesto

Now, some people are still not convinced. They want more power. And that’s fine. Maybe I’ll stack two Vidar transformers in a Tyr chassis and do a 300WPC stereo amp. Probably not, because it would also require a panic fan, and I hate fans, but after last year’s ordering debacle, we got lots of Vidar transformers to play with.

But I’d say, keep an open mind. You might be surprised.

We’re sooooooo conditioned to want more, more, mooore, moaaarrr! that I think sometimes we lose perspective, like I did when I started this amp adventure. And that can quickly devolve into venerating something that can produce huge power above everything else—even if we don’t need that power.

I mean, here’s the thing. I’ve had desktop systems for ages. A lot of them used a 60W integrated amp—first the Sumo Antares prototype, then the Ragnarok, then the Rag 2. And each of them had a common denominator: I never used even a fraction of those amp’s output power.

And yeah, I’ve also had desktop systems based on powered monitors. Including ones that like to brag they have like 1000W for the woofer and 50,000W for the tweeter and that sounds like 10,000,000W and etc. (Well, maybe a bit of hyperbole there, but you know what I mean: powered monitors with a bunch of watts and claims of hitting 1XXdB at 1 meter and other silly numbers.

And each time, those mega-powered systems were used once for that circus trick of huge output—then turned down for use at regular listening levels.

Because, you know, yeah, they go loud, but Rina’s yelling at me from the other room.

And each time, those mega-powered systems didn’t last long on the desktop—their infernal hisssssssssssssssssssssss drove me bonkers, and I went back to passive.

So, yeah, something used for a party trick once (but then annoys the neighbors) with the added bonus of the unrelenting hiss of a demonic cat drilling its way into your ears…yeah, no thanks, not for me.

Aside: and yes, I know, there are pros that have legit uses for such monitors, and people who don’t have to worry about neighbors. Not dissing those. Just asking: do you really need it? Can you use it? Or is it just crazy numbers-for-sake-of-numbers, power-nervosa specsmanship?​

Sooooo…maybe it’s time to recalibrate.

To sit back, and think, “Do I really need power for the sake of power?”

Yes. I know. It’s a challenging idea.

But maybe, just maybe, it’s time for something less power, more better.

 —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.

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The post Audio amplifiers: How much power (and at what tradeoffs) is really required? appeared first on EDN.

This project came about because I wanted to experiment with my new oscilloscope but had no way to generate the needed signals. So, I decided to put something together myself. Right now, it can produce: RS232 serial output I²C signal output Positive and negative runt pulses Burst pulses Classic waveform generators: Sine, Triangle, Sawtooth Amplitude modulation (AM) wave patterns The hardware-specific parts are kept separate from the hardware-independent parts, so it should be relatively easy to adapt this for a different microcontroller or DAC. I also designed a PCB for it — my first ever! Routing the traces was a bit tricky, but it was a fun learning experience. Feedback and suggestions are always welcome. https://github.com/coderarjob/ScopeTester submitted by /u/arjobmukherjee [link] [comments]

submitted by /u/DropMysterious1673 [link] [comments]

submitted by /u/SubhajitBarman [link] [comments]

A small microphone I designed for Hack Club's Highway to Hardware program! Still needs some modifications to work properly for daily use - but still incredibly happy it works! The build was supported by Hack Club, a not-for-profit for supporting teenagers to create and build hardware and software! All the design files are available on Github at: https://github.com/ConfusedHello/USB-Mic submitted by /u/ConfusedHornPlayer [link] [comments]

The new 3.3 V, four-channel hybrid redrivers may promote HDMI signal integrity for high-fidelity video transmission.

I found a 24v led strip but because I didn't have anything to control it, I decided to make a pcb to do so! It's very overpowered for what I currently use it for, but because of the way it's designed and the psu, i could maybe power 50 meters! Everything including firmware is open source at https://github.com/espcaa/led-system submitted by /u/espcaaa [link] [comments]

Diodes’ AP7372 low-dropout (LDO) regulator offers high power supply ripple rejection (PSRR) and low output noise for precision signal chains. It powers ADCs, DACs, VCOs, and PLLs, helping meet stringent ripple and noise targets in test and measurement, communication, industrial automation, and medical applications.

The AP7372 maintains just 8 µVRMS output noise, independent of fixed output voltage, and delivers PSRR of 90 dB at 10 kHz, 70 dB at 100 kHz, and 52 dB at 1 MHz. Operating from 2.7 V to 20 V, it provides up to 200 mA of output current with a typical 120-mV dropout voltage at 200 mA The wide input range covers common rails (19.5 V, 12 V, 5 V) and single-cell Li-ion sources, while outputs from 1.2 V to 5.0 V suit analog and mixed-signal loads.

Four fixed-output voltages are available—1.8 V, 2.5 V, 3.3 V, and 5.0 V—along with an adjustable output down to 1.2 V. A dedicated resistor-divider pin allows fine adjustments above the nominal fixed-output values. The LDO also provides an enable pin for system-level control, such as power-up sequencing or shutdown when the regulator is unused. Shutdown current is approximately 3 µA, with a quiescent current of 66 µA.

The AP7372 LDO regulator costs $0.30 each in 1000-piece quantities.

AP7372 product page

Diodes

The post Regulator delivers clean power to sensitive circuits appeared first on EDN.

A 60-A eFuse from Alpha & Omega, the AOZ17517QI, is optimized for 12-V input power rails in servers, data centers, and telecom infrastructure. Operating from 4.5 V to 20 V (27 V absolute maximum), it safeguards the main input bus from interruptions caused by abnormal loads or fault conditions.

The eFuse co-packages a high-performance IC with protection features and a high-SOA trench MOSFET, which serves as the device’s controllable power switch. It continuously monitors current through the MOSFET, limiting it if it exceeds the set threshold. If the overcurrent persists, the switch turns off, safeguarding downstream devices much like a conventional fuse.

MOSFET on-resistance of 0.65 mΩ isolates the load from the input bus when the eFuse is off. Built-in startup SOA management and additional protections enable glitch-free system power-up and safe hot-plug operation.

The AOZ17517QI offers auto-restart or latch-off options. Prices start at $1.80 each in 1,000‑unit quantities. It is available now in production quantities, with a lead time of 14 weeks.

AOZ17517QI product page

Alpha & Omega Semiconductor 

The post eFuse limits current on server input rails appeared first on EDN.

Knowles’ Cornell Dubilier Type BLS DC-link capacitors operate in harsh environments with temperatures up to 125°C. The company reports the capacitors exceed industry standards in temperature-humidity bias (THB) testing, achieving a 100% longer lifespan than comparable devices.

The series undergoes 2000 hours of THB testing at 85°C and 85% relative humidity at rated voltage. Type BLS capacitors also meet automotive-grade electrical and mechanical requirements per AEC-Q200, ensuring reliable operation under high temperature and moisture conditions.

Type BLS DC-link capacitors operate across a wide temperature range, from –55°C to 125°C, maintaining stable capacitance and low ESR even under the thermal stress of high-speed SiC switching. They offer capacitance values from 1 µF to 220 µF and voltage ratings between 450 VDC and 1100 VDC.

Encased in UL94-V0 rated plastic with thermosetting resin potting, the capacitors resist solvents and mechanical stress for long-term durability. Versatile mounting options allow horizontal or vertical board placement with 2- or 4-pin configurations.

Check availability, request samples, or get a quote on the product page linked below.

Type BLS product page

Cornell Dubilier  

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TDK has added three new models to its SD0201 series of TVS diodes for USB Type-C, HDMI, DisplayPort, and Thunderbolt connections. They protect sensitive circuits in smartphones, laptops, wearables, and networking devices from ESD and transient surges.

Each component comes in a 0201 chip-scale package with dimensions of 0.58×0.28×0.15 mm, suited for space-constrained designs. With working voltages of ±1 V, ±2 V, and ±3.6 V, the TVS diodes meet the IEC 61000-4-2 standard for ESD robustness up to ±15 kV and handle surge currents up to 7 A, depending on the variant. Their symmetrical design enables bidirectional protection for I/O interfaces, and they feature low leakage current with dynamic resistance down to 0.16 Ω.

The three new devices in the SD0201 series differ in their DC working voltages and parasitic capacitances:

• SD0201SL-S1-ULC101 (B74121U1036M060): ±3.6 V, 0.65 pF
• SD0201-S2-ULC105 (B74121U1020M060): ±2 V, 0.7 pF
• SD0201SL-S1-ULC104 (B74121U2010M060): ±1 V, 0.15 pF

Datasheets for the TVS diodes are available for downloading on the product page linked below.

SD0201 series product page

TDK Electronics

The post TVS diodes shield consumer electronics interfaces appeared first on EDN.

Fabless semiconductor company Montage Technology is now sampling its clock buffers and spread-spectrum oscillators, following the mass production of its clock generators. Designed for precise, low-jitter performance, these devices deliver reliable timing for AI servers, communication infrastructure, industrial control systems, and automotive electronics.

Clock chips generate the reference signals that maintain synchronization across system components. Leveraging expertise in mixed-signal IC design, core I/O technology, and PLL integration, Montage’s portfolio supports complete clock tree implementations, enhancing timing accuracy and system efficiency in a range of applications.

The timing portfolio includes clock generators with up to four independent differential outputs and clock buffers with four to ten scalable outputs for lossless signal distribution. It also features spread-spectrum oscillators that suppress EMI to enhance system stability. The devices deliver low output phase noise and offer flexible per-channel configuration—covering I/O type, drive strength, voltage, frequency, and spread spectrum—for precise receiver alignment.

Montage offers six clock generator models now in mass production, along with twenty clock buffer models and four spread-spectrum oscillators available for sampling. For more information, visit the product page linked below or email globalsales@montage-tech.com.

Clock chip product page 

Montage Technology 

The post Montage broadens timing device lineup appeared first on EDN.

Пам'яті Федіра Федоровича Дубровки kpi чт, 08/14/2025 - 21:40

submitted by /u/james__hi [link] [comments]

New AI upscaling tech points to a 2026 mobile graphics future driven by on-chip inference.

Digital acquisition instruments like oscilloscopes and digitizers are incorporating increasingly large acquisition memories. Acquisition memories with lengths in the gigasample (GS) range are commonly available. The advantage of long-acquisition memories is that they can capture longer-time records. They also support higher sampling rates at any given record duration, providing better time resolution.

The downside of these long records is the time required to analyze them. Most users couple the instrument to a host computer and transfer the data records to the host computer for post-acquisition analysis.

The longer the record, the longer the transfer time and the slower the testing. Many instruments have added tools to allow internal analysis within the instrument, allowing only the results of the analysis to be transferred instead of all the raw data. This can save a great deal of time during testing. This article will investigate the use of several of those analysis tools.

Case study: The startup of an SMPS

Testing the startup of a switched-mode power supply (SMPS) provides an example of a relatively long acquisition. Figure 1 shows an example of a 10-ms acquisition covering the startup of an SMPS.

Figure 1 A 10-ms acquisition showing the startup of an SMPS, including the drain-to-source voltage (channel 1-yellow), drain current (channel 2-red), and gate drive voltage (channel 3-blue) of the FET switch. Source: Art Pini

This record, sampled at 250 megasamples per second (MS/s), has 2.5 million samples per channel. That is a lot of data to render on a screen with a 1920 x 1080 pixel resolution. The oscilloscope acquires and stores all the data, but when more than 1920 samples are being displayed, it compacts the displayed data. Rather than just sparse the signal records, which might cause the loss of significant data points, it detects the significant peaks and valleys and includes those values on the display. This enables users to find significant events within the compacted displays.

Basic measurements

There are three acquired waveforms. The drain-to-source voltage (VDS), drain current (ID), and gate-to-source voltage (VGS) of the primary FET switch. The test will look at the variation in these signals as the power supply controller powers up the supply. Some basic measurements of the signal amplitudes are made and displayed. The peak-to-peak amplitudes of VDS and ID, as well as the amplitude of VGS, are shown as parameters P1, P2, and P3, respectively.

The frequency of the VGS signal and the number of edges contained in the acquisition appear as parameters P4 and P5. Amplitude measurements are taken once per acquisition. Time measurements such as frequency, period, width, and duty cycle are made once per waveform cycle. So, the frequency measurement includes all 1163 cycles acquired. This is an example of “all instance measurements.” This feature ensures that every cycle in the signal is captured in the measurement.

Zoom in on the details

All the acquired data is stored in the instrument’s acquisition memory and can be expanded using zoom traces to see the details, as shown in Figure 2.

Figure 2 Zoom traces provide horizontally or vertically expanded views of the acquired traces, allowing detailed study of the elements of each acquired waveform. Source: Art Pini

In the figure, the zoom traces of the acquired waveforms are horizontally expanded and displayed at 5 ms per division, with a horizontal expansion of 200:1. The zoom traces are taken from the area of the acquired waveform highlighted with higher intensity. The SMPS uses pulse width modulation (PWM) to control its output power.

The zoom traces show the variations in the amplitude and duty cycle of the waveforms just after the gap at 456 ms in the acquired waveforms. The zoom traces are locked together to keep the displayed waveform time synchronous. They can be scrolled horizontally or vertically to show the details in any part of the source waveforms.

Finding desired events in long records

The question of locating areas of interest in these long acquisitions has several answers. Histograms of measured parameters can display the range of values and the number of measurements made by the instrument. A measurement track displays any measurement value versus time. The track can be aligned with the source waveform to show where in the acquisition that value occurs. Some instruments offer scanning functions to map where, in the long record, specific values of a measured parameter occur. These features are extremely useful in analyzing long records.

Histograms

A histogram plots the number of measured values occurring in a small range of measured values (known as a bin) against the nominal measured value. It counts the number of measurements in each bin. Figure 3 shows a histogram measuring the duty cycle of the VGS waveform.

Figure 3 The histogram of the duty cycle measurement of the VGS waveform shows the distribution of measured values with a mean value of 28.4%, a maximum value of 38.9%, and a minimum value of 0.3%. Source: Art Pini

The histogram shows the range of values encountered in a measurement. This example shows that the most commonly occurring value of the duty cycle is 31.6%. This is read from the X@peak parameter (P4). The range of duty cycle values is from 0.3 to 38.9%. This data is based on 1164 measurements shown in the total population measurement (totp – P8). How is the location of the maximum value of the duty cycle found? A measurement track matches measurements to a specific cycle in the acquired waveform.

Measurement track

A measurement or parameter track is a waveform comprised of a series of measured parameter values plotted against time at the same sample rate as the source waveform on which the measurement was made. It is time synchronous with the source waveform.

Figure 4 is an example of a measurement track based on the duty cycle at level (duty@lv) measurement of the VGS waveform.

Figure 4 The trace F1 is the track of duty@lv parameter (P1) values over the entire acquisition. It is time synchronous with the trace of channel 3. Source: Art Pini

The track function, located beneath the source waveform, illustrates how the duty cycle of the gate drive signal changes over time during SMPS startup. After a brief gap, it rises steadily until it reaches a plateau, then drops to a relatively stable value.

The parameter maximum (max-P2) reads the maximum value of the duty cycle as 38.59%. The parameter horizontal location of the maximum (x@max-P3) locates the maximum at 3.12 ms after the trigger (zero time). The parameter markers (blue dashed lines) mark these values on the track display. The center of the zoom traces can be set to 3.12 ms, and the zoom traces are expanded about that point to show the specific cycle of each waveform with the maximum duty cycle.

The VGS voltage appears in zoom trace Z3. The duty cycle at level is read for that specific cycle of the VGS signal in parameter P4, confirming that it is the cycle with the maximum duty cycle value. The track function helps locate specific waveform events within the long record without manually scrolling through the whole waveform to find them.

Tracks can show a variety of characteristics, such as peaks, valleys, periodicity, or rate of change. Periodicity in a track of frequency or phase provides information about frequency or phase modulation, respectively. In this example, the track has a nearly linear slope as the controller adjusts the duty cycle. The rate of change is of interest and can be easily measured, as shown in Figure 5.

Figure 5 Using the relative horizontal cursors to determine the rate of change of the duty cycle of the VGS waveform over the linearly changing portion of the track. Source: Art Pini

The relative horizontal cursors read the slope of the waveform between the cursor lines. This value is displayed and highlighted by an orange box in the waveform annotation box for the math trace F1 as 7.03 k% per second (7% per millisecond).

WaveScan—automatic scan and search of long waveforms

The oscilloscope used in this example has a scan and search engine called WaveScan that can locate unusual events in a single capture or scan for a specific measurement event in multiple acquisitions over a long period. WaveScan has over twenty search modes for analog or digital channel acquisition events. Figure 6 shows an example of a search using WaveScan to find all instances of a duty cycle measurement greater than 38%.

Figure 6 Using WaveScan, an automatic search tool, to search the VGS waveform for duty cycle values greater than 38%. Source: Art Pini

The WaveScan setup dialog box shows the search criteria set up to find duty cycle values greater than 38%. WaveScan can search based on measurements, waveform edges, non-monotonic edges, and serial data patterns. A numeric search, such as those on measurements, can be based on values greater, less, than, within a range, outside of a range, or for the rarest events.

In the example, the search is based on measuring the duty cycle at level with values greater than 38%. The search results are marked with red lines on the source trace and appear in the table in the upper left corner. Each event matching the search criteria is listed in the table in the order of occurrence. The maximum duty cycle value of 38.859%, located previously, is item 3. The table entries are hyperlinked to the Zoom trace, and if one is selected, it will center that event in the Zoom trace. In the example, event six is selected. The zoom trace Z1 has been centered on the sixth cycle with a duty cycle greater than 38%, highlighting its location at 3.2295 ms.

Post-acquisition analysis tools

Modern instruments offer longer acquisition times and include a host of tools to aid in analyzing the data generated. Features such as compaction, zoom, histograms, track, and WaveScan enable various analyses and measurements. The tools also augment the measurements by annotating them numerically or graphically on the display. These features enable local analysis, which accelerates testing and reduces the amount of data that needs to be transferred to external computers.

Arthur Pini is a technical support specialist and electrical engineer with over 50 years of experience in electronics test and measurement.

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