Новини світу мікро- та наноелектроніки

Two analog signal generators from Keysight enable component and device characterization at frequencies up to 26 GHz. The AP5001A RF signal generator covers 9 kHz to 6.1 GHz, while the AP5002A microwave signal generator spans 9 kHz to 26 GHz. Their compact, lightweight design allows easy transport and efficient use of lab space.

Both generators deliver accurately leveled output power at 1 GHz, ranging from -120 dBm to +17 dBm for the AP5001A and up to +23 dBm for the AP5002A. Each instrument provides an OCXO-stabilized signal with -130 dBc/Hz phase noise at 1 GHz and a 20 kHz offset, ensuring mHz resolution for precise measurements. The fast switching speed of the AP5001A, as low as 20 µs, accelerates testing and increases throughput.

Keysight’s analog signal generators offer modulation capabilities, including AM, FM, PM, pulse, pulse train, and frequency chirps. They come equipped with an LCD touch screen, remote desktop software, and a carrying handle. The company states that the generators are future-ready, with all frequencies and options available for license upgrades.

Prices for the AP5001A and AP5002A signal generators start at $7357 and $17,850, respectively.

AP5001A product page

AP5002A product page

Keysight Technologies

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Offering Limited Power Source (LPS) functionality, the AOZ1390DI ideal diode protection switch from AOS improves the efficiency and safety of USB Type-C applications. LPS limits the current and voltage supplied to the load, protecting sensitive components from conditions such as overcurrent and overvoltage.

In multiport ORing or parallel power applications, the LPS(B) pin of the AOZ1390DI can be connected to the Disable(B) pin of one or more AOZ1390DI devices across different ports. The LPS feature acts as a watchdog, disabling the port if another port in the same system is faulty or damaged. The ability to prevent excessive power flow from malfunctioning ports makes the AOZ1390D1 well-suited for multiport USB-C Power Deliver (PD).

The AOZ1390DI features Ideal Diode True Reverse Current Blocking (IDTRCB), effectively preventing undesired reverse current from VOUT to VIN. An integrated back-to-back MOSFET provides a typical on-resistance of 18 mΩ and a high Safe Operating Area (SOA).  Input operating voltage ranges from 3.3 V to 23 V, with both VIN and VOUT terminals rated for an absolute maximum of 30 V. 

The AOZ1390DI ideal diode protection switch is available in two variants. The -01 variant automatically restarts after fault conditions are cleared, while the -02 version latches the power switch off.

Both the AOZ1390DI-01 and AOZ1390DI-02 cost $1.40 each in lots of 1000 units. They are available in production quantities with a standard lead time of 12 weeks.

AOZ1390DI-01 product page

AOZ1390DI-02 product page

Alpha & Omega Semiconductor 

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

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The Achronix Speedster AC7t800 FPGA delivers 12 Tbps of fabric bandwidth, making it well-suited for AI/ML, 5G/6G, and data center applications. Manufactured on TSMC’s 7-nm FinFET process, this midrange FPGA features a 2D network-on-chip (2D NoC) for 12 Tbps bandwidth, 864 machine learning processors, and six GDDR6 subsystems (including controller and PHY) that provide 1.5 Tbps of external memory bandwidth. It also supports double-bit error detection and single-bit error correction.

The AC7t800 supplies 711,000 logic elements (LEs), the equivalent of 730,000 system logic cells (LCs). Along with GDDR6 interfaces, the FPGA provides two 400-Gbps Ethernet channels, 16 PCIe Gen5 lanes, and 24 12-Gbps serializer/deserializer channels. The device’s 2D NoC facilitates connections among all interconnects, I/O, memory, internal functional blocks, and the FPGA fabric. According to Achronix, the 2D NoC reduces routing congestion by as much as 40% compared to conventional FPGAs.

Samples of the AC7t800 FPGA are available now.

AC7t800 product page

Achronix Semiconductor 

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

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ST has launched a page EEPROM that provides the speed and density typical of serial flash, combined with the byte-level flexibility of EEPROM. The SPI page EEPROM family offers densities of 8 Mbits, 16 Mbits, and 32 Mbits, significantly increasing storage compared to standard EEPROMs. These devices can be used in wearables, healthcare devices, asset trackers, e-bikes, and other industrial and consumer products.

Embedded smart page management allows byte-level write operations for processes like data logging, while also supporting page/sector/block erase and page programming up to 512 bytes for handling firmware OTA updates. The devices also offer buffer loading, which can program several pages simultaneously. The data-read speed of 320 Mbps is about 16 times faster than standard EEPROM, while write-cycle endurance of 500,000 cycles is several times higher than conventional serial flash.

With peak current control, page EEPROM minimizes power supply noise and prolongs the runtime of battery-operated equipment. According to ST, the write current is below that of many conventional EEPROMs, and there is a deep power-down mode with fast wakeup that reduces the current to below 1 µA.

The M95P08, M95P16, and M95P32 page EEPROMs are in production now, with prices starting at $0.50 for the 8-Mbit MP95P08.

STMicroelectronics

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Semtech’s single-channel LoRaWAN hub evaluation kit supports smaller-scale network deployments, such as SMB and smart home applications. Designed for low-density networks of up to 50 end devices, the kit is compatible with the LoRaWAN standard and LoRaWAN 1.0.x devices. It uses Wi-Fi for backhaul and can be configured via an embedded webpage.

This turnkey solution provides basic LoRaWAN connectivity and supports several Semtech LoRa sub-GHz transceivers, including the SX1261, SX1262, SX1268, LR1121, and LLCC68. The LRWHUB1EVK1A evaluation kit features a shield adapter board with an Espressif ESP32-S3, a low-power MCU-based SoC with integrated 2.4-GHz Wi-Fi and Bluetooth LE. Additionally, the kit comes with a separate OLED display adapter board. It requires a LoRa radio shield, sold separately.

Global analyst Omdia predicts LoRaWAN to have the greatest annual growth, at 30% over the 2023-2030 forecast period. “It is a comparatively recent technology finding a niche in longer-distance, lower-power applications like irrigation systems and security sensors for property perimeters,” noted Omdia senior research director, Edward Wilford. “The cost effectiveness of Semtech’s one-channel hub aligns well with such smaller-scale applications.”

For more information about Semtech’s LRWHUB1EVK1A single-channel LoRaWAN hub evaluation kit and reference designs, click here.

Semtech

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

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A new neuromorphic element called a “spin-memristor” mimics the energy-efficient operation of the human brain to reduce the power consumption of artificial intelligence (AI) applications to 1/100th of traditional devices. TDK developed this “spin-memristor” as the basic element of a neuromorphic device in collaboration with the French research outfit CEA.

It’s apparent by now that energy consumption utilizing big data and AI will boom, inevitably leading to complexity around the computational processing of vast amounts of data. So, TDK aims to develop a device that electrically simulates human brain’s synapses: the memristor.

Figure 1 The “spin-memristor” has been demonstrated to function as the basic element of a neuromorphic device. Source: TDK

Here, it’s important to note that conventional memory elements store data as either 0 or 1. On the other hand, a spin-memristor can store data in analog form, just as the brain does. That enables it to perform complex computations with ultra-low power consumption.

While memristors for neuromorphic devices already exist, they face critical challenges, including changes in resistance over time, difficulties in controlling the precise writing of data, and the need for control to ensure data is retained. TDK’s spin-memristor overcomes these issues and provides immunity to environmental influences and long-term data storage while reducing power consumption by cutting leakage current.

Practical applications

After jointly developing spin-memristor with CEA, TDK is partnering with the Center for Innovative Integrated Electronic Systems at Tohoku University to create practical applications for this device. While the tie-up between TDK and CEA has demonstrated that spin-memristors can serve as the basic element of a neuromorphic device, manufacturing them requires the integration of semiconductor and spintronic manufacturing processes.

Spintronics is a technology that utilizes both the charge and spin of electrons or the spin element alone. TDK’s AI semiconductor development program, in collaboration with Tohoku University, will work on fusing memristors with spintronics technology.

Figure 2 TDK is collaborating with Tohoku University to develop practical applications for spin-memristors. Source: TDK

It’s worth noting that the integration between semiconductor and spintronic manufacturing processes has already been accomplished in a similar product: MRAM. TDK chose Tohoku University as its partner mainly because it’s a leading academic institution in MRAM research and development.

Related Content

• Will memristors prove irresistible?
• Memristor emulates neural learning
• Knowm’s memristors alive and shipping
• How Memristors Could Help Drive AV Evolution
• Memristor Computer Emulates Brain Functions

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Announced at AutoSens Barcelona, the OX12A10 is the highest resolution sensor in the TheiaCel product family, ideal for ADAS and AD, and features OMNIVISION’s new a-CSP+ ultra-small package technology

The 12MP OX12A10 is the highest-resolution sensor in OMNIVISION’s 2.1-micron (µm) TheiaCel product family, which also includes the 8MP OX08D10 and 5MP OX05D10 devices. TheiaCel harnesses the capabilities of next-generation lateral overflow integration capacitors (LOFIC) and OMNIVISION’s DCG high dynamic range (HDR) technology to eliminate LED flicker regardless of lighting conditions. OMNIVISION’s TheiaCel solution also achieves a wider dynamic range than earlier automotive HDR architectures.

The post OMNIVISION Expands TheiaCel Product Portfolio with New 12MP-resolution Image Sensor for LED-Flicker-free Automotive Cameras appeared first on ELE Times.

Books have always been a window into new worlds. The ability to access them without breaking the bank is more important than ever. E-libraries offer readers an affordable and flexible way to enjoy countless titles. Zlibrary is your chance to explore the world of books without paying. This means more people can dive into the joy of reading without worrying about high costs. But how exactly do e-libraries make reading accessible to everyone? Let’s break it down.

Easy Access and a Wide Selection

E-libraries remove the barriers that come with traditional books. Physical libraries require trips across town and can have limited copies. On the other hand, e-libraries are accessible from anywhere at any time. Readers can enjoy a wide variety of titles including rare and out-of-print works without waiting for availability. This kind of access helps readers save both time and money.

Beyond easy access, e-libraries also provide a wide selection of genres. From classic literature to modern bestsellers every reader can find something suited to their taste. Traditional bookstores often have high prices for popular books while e-libraries offer the same material at much lower costs. The options are endless and the best part is you don’t need to worry about shipping or storage.

The key factor that makes e-libraries an affordable option is the pricing model. Some e-libraries offer free access while others charge minimal subscription fees. Compared to buying physical books or even e-books individually, e-libraries allow users to read a vast number of titles for a fraction of the cost.

Not only do these platforms save you money but they also remove the hassle of managing your personal collection. There’s no need to buy new shelves or find storage space for your favorite books. Everything is stored digitally in a single place.

E-libraries contribute to affordability in another way too. By reducing the need for printed materials they help save resources. Less paper fewer deliveries and reduced printing costs all contribute to lower prices. E-libraries are an environmentally friendly option that passes on the savings to readers.

In the long run the value of e-libraries only grows. As digital libraries expand their collections readers gain more access without the need to keep buying. It’s an investment that pays off over time. You get the latest releases as well as timeless classics all under one virtual roof. This adds long-term value to your reading experience while keeping expenses low.

E-libraries are not just for leisure reading. They offer rich educational resources for readers of all ages. Students, researchers and lifelong learners can access academic texts, textbooks and research papers at minimal cost. Traditional textbooks and reference materials are often expensive but e-libraries provide these resources for little to no cost making education more affordable.

Parents can also use e-libraries to introduce children to reading. Interactive and illustrated e-books offer a fun way to spark a love for literature in young minds. By using digital platforms kids can explore a range of genres and topics without the cost of buying new books.

The post What Makes E-Libraries an Affordable Option for Readers? appeared first on Electronics Lovers ~ Technology We Love.

Analog-to-digital conversion based on the classic combination of a voltage-to-frequency converter (VFC) with a counter has been around for (many) decades, mainly because it has some durable time-proven advantages. VFC digitization is naturally integrating, so high noise rejection is inherent, as is programmable resolution (if you want more bits, just count longer). Unfortunately, high conversion speed is not. 

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

Useful resolution (8 or more bits) tens-of-microseconds VFC conversion times require tens-of-megahertz output frequencies. There are existing VFC designs that can flap that fast, e.g., Jim Williams’s awesome 100 MHz King Kong  and my own “20 MHz VFC with take-back-half charge pump”. However, these possible solutions only pose another potentially pesky problem. What to use for a counter?

Frequently (no pun intended) the ideal and most cost-effective digital partner for a VFC is the µC’s onboard counter-timer peripheral (CTP), typically providing 16 bits of resolution at zero added parts cost. Unfortunately, the necessity of taking multiple (e.g., four) samples of each cycle of incoming pulses by onboard CTP logic limits maximum count rate to a fraction (typically ¼) of the µC’s internal clock.  

Thus, for a 20-MHz internal clock, 5 MHz is the fastest achievable CTP count rate. Sorry, Kong.

Of course, an external hardwired counter peripheral could be implemented that would easily accommodate fast VFCs (okay, maybe Kong not so totally easy), but cost, parts count, and board area make this option quite unattractive.

Shown in Figure 1 is a compromise topology that combines the CTP doing what it does best (providing lots of bits), with a single external 4-bit MSI pre/scaler/accumulator chip. This extends the peripheral’s speed by up to 16x (hence up to 80 MHz with a CTP 5-MHz top end), at the cost of (at most) four additional general purpose I/O (GPIO) pins.

Here’s how it works.

Figure 1 100-MHz MSI counter prescales and accumulates VFC LSBs so clunky CTP can cope.

1. Five GPIO pins are programmed for interface with the preaccumulator: 
   1. Four as inputs (IN1 through IN4)
   2. One as output (OUT). 
2. IN4 is also programmed for input to the selected CTP, which is programmed for 16-bit accumulation.

Each VFC integration cycle comprises the following steps:

1. OUT = 0 to disable counting.
2. A 20-bit initial value (X1) is formed by concatenating the states of the INx bits (as 4 LSBs) with the 16 bits of the CTP (as 16 MSBs), i.e., X1=[cccc cccc cccc cccc iiii].
3. OUT = 1 for the desired integration interval.  A practical maximum = 220/VFCmax, shorter if lower resolution and/or higher conversion speed is required.
4. OUT = 0 to freeze counting.
5. A 20-bit final value (X2) is formed by concatenating INx with the CTP.
6. The 20-bit conversion result = X2 – X1 modulo 220.

Note that if the ratio of max VFC output to max CTP count rate is less than 8x, then only three INx pins need be allocated to the interface (Xx = [ccc cccc cccc ciii]), with IN3 programmed as CTP input. If less than 4x, then only two, (Xx = [cc cccc cccc ccii]). And so forth.

If simpler arithmetic is more important than conserving GPIO pins, then a sixth output pin can be connected to and pulsed low at the onset of conversion to reset the INx bits to zero, along with a similar preload of the CTP bits. This would eliminate steps #6 and #10 of the conversion sequence.

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

• 20MHz VFC with take-back-half charge pump
• Voltage inverter design idea transmogrifies into a 1MHz VFC
• Single supply 200kHz VFC with bipolar differential inputs
• New VFC uses flip-flops as high speed, precision analog switches

The post Preaccumulator handles VFC outputs that are too fast for a naked CTP to swallow appeared first on EDN.

At this year’s electronica in Munich, Germany, GOEPEL electronic is presenting groundbreaking innovations at booth A3.351 that will attract a lot of industry attention!

In the world of Embedded JTAG solutions, AI support has been massively expanded, taking CASCON software to a new level. With the Smart Test Coverage Analyzer (smartTCA), GOEPEL electronic is demonstrating the world’s first tool for AI-supported test coverage analysis for use with embedded instruments. Based on training from over 1000 projects, the AI process recognizes the structural elements and architecture of the board and, with the help of a transformation process, calculates a theoretically possible test coverage at pin, net, and device level. This enables users to assess the potential of using embedded instruments in a focused way and implement appropriate test strategies.

FlashFOX is also making a big appearance again: the award-winning stand-alone 8-channel programmer impresses with unique features such as WLAN connectivity, an integrated JAM/STAPL player, and a web interface. Other new features, such as the ADYCS automation feature and the new streaming mode, make programming microcontrollers, flash components, and PLD/FPGAs even faster and more flexible. A must for every modern production, especially now that it is also available as a 4-channel version.

Furthermore, the SCANFLEX-TIC portfolio has been expanded, adding the SFX II TIC01/VX plug-in variant with 5V support and the SFX II TIC422/S(R) external add-on variant. Both modules are compatible with preceding TIC variants and have programmable interface parameters.

A new expansion module available for the integration package for Acculogic Flying Prober FLS 980 Dxi enables the automatic generation of interactive tests, thus ensuring maximum transparency as well as high test coverage.

In the field of inspection solutions, the new modular system platform Multi Line sets unique accents: It covers a wide range of configuration options for the quality assurance of electronic assemblies – from component and solder joint inspection (AOI for SMT), solder paste inspection (SPI), inspection of THT components and their solder joints (AOI for THT), to conformal coat inspection (CCI). The flexible all-rounder allows the inspection of PCBAs in the various transport levels of the THT process as well as the double-sided inspection of SMT assemblies without flipping the boards. A uniform system software makes it possible to reduce training costs, facilitates flexible deployment of operators, and saves overall resources.

Multi Line CCI inspects conformal coating fully automatically. Fluorescent coating are made to glow by UV LEDs of different wavelengths. A telecentric lens and a color camera deliver high-contrast 2D images for evaluation. Quick inspection program creation is based on CAD data in combination with an importable coating plan. Coated assemblies can be inspected simultaneously from above and below. It is also possible to return assemblies and product carriers with an optional conveyor in the lower part of the system.

Multi Line Assist, also on display at booth A3.351, is an ingenious addition to the Multi Line system family. The new generation of the AOI module for THT assembly monitors the presence of THT components, their positions, polarity, colors, 2D codes, and labels. It is available in three resolution variants for different requirements and inspection areas. An innovative ambient light suppression enables reliable test results even when the ambient lighting changes. The image brightness is no longer controlled by the intensity of the illumination at the assembly station, but rather by the exposure time of the 47-megapixel camera. This keeps the lighting constant for the personnel at the assembly station. In addition, Multi Line Assist can be combined with a projection unit to support staff during the placement process.

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• Accelerate wireless product development and manufacturing with outstanding output power range, signal purity, and speed

Keysight Technologies, Inc. has expanded its signal generator portfolio with two new analog signal generators, an RF Analog Signal Generator and a Microwave Analog Signal Generator. These new solutions provide radio frequency (RF) engineers with portable and compact tools for component and device characterization at frequencies up to 26 GHz.

RF engineers rely on signal generators to develop and test components and devices across consumer electronics, wireless networks, radar systems, and more. These tools are essential for producing continuous waveform and analog modulation signals during the design and testing process.

• Portability: Compact size and lightweight design for easy transport and efficient use of lab space.
• Versatile power range: Accurately leveled output power from -120 dBm up to +23 dBm, suitable for various RF and microwave applications.
• Low phase noise: Oven controlled crystal oscillator stabilized signal (phase noise -130 dBc/Hz at 1 GHz, 20 kHz offset) with mHz resolution ensures the measurement accuracy.
• Rapid testing: Fast switching speed (down to 20 µs) accelerates testing and boosts throughput.
• Extensive modulation capabilities: Supports amplitude modulation , frequency modulation, phase modulation , pulse modulation, pulse train and frequency chirps.
• Optimized user interface: Features an LCD touch screen and remote desktop PC software making it easy to operate.
• Future-ready: All frequencies and options are license upgradeable.

Joe Rickert, Vice President and General Manager, Keysight High Frequency Measurements Center of Excellence, said:  “The new RF Analog Signal Generator and the new Microwave Analog Signal Generator   provide RF engineers  with general purpose tools that deliver reliable signals with wide output power range, excellent signal purity, and fast switching speed in a compact size, for wireless communications, digital design, and radar applications.”

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• Strategic collaboration will pair STMicroelectronics’ market-leading STM32 microcontroller ecosystem and Qualcomm’s world-leading wireless connectivity solutions.
• Seamless integration into existing STM32 developer ecosystem to allow simple, fast, and cost-effective design of next-gen industrial and consumer IoT applications augmented by edge AI.

STMicroelectronics, a global semiconductor leader serving customers across the spectrum of electronics applications, and Qualcomm Technologies International, Ltd., a subsidiary of Qualcomm Incorporated, has announced a new strategic collaboration for the next generation of industrial and consumer IoT solutions augmented by edge AI. This highly complementary collaboration will see the two companies integrate Qualcomm Technologies’ leading AI-powered wireless connectivity technologies, starting with Wi-Fi/Bluetooth/Thread combo system-on-a-chip (SoC), with the market-leading microcontroller (MCU) ecosystem from ST. Through this collaboration, developers will enjoy seamless connectivity software integration into STM32 general-purpose MCUs, including software toolkits, facilitating quick and broad adoption via ST’s world-wide sales and distributor channels.

Remi El-Ouazzane, President, Microcontrollers, Digital ICs and RF Products Group, for STMicroelectronics said: “Wireless connectivity is key to the fast pervasion of edge AI across an ever-growing variety of use cases in enterprise, industrial and personal applications. This is why we are establishing a strategic collaboration with Qualcomm Technologies on wireless connectivity today, starting with Wi-Fi/BT/Thread combo SoC, and already considering next steps, complementing our existing multi-protocol Bluetooth Low Energy, Zigbee, Thread and sub-GHz products portfolio. We envision wireless connectivity products based on technology from Qualcomm Technologies augmenting any of our STM32 products, bringing significant value to our more than 100,000 STM32 customers globally.”

Rahul Patel, Group General Manager, Connectivity, Broadband and Networking Business Unit for Qualcomm Technologies, Inc. said: “Qualcomm Technologies’ research and development leadership has helped drive the evolution of wireless IoT, ranging from pioneering 4G/5G, to high performance Wi-Fi, to micropower connectivity solutions. Our collaboration with STMicroelectronics pairs Qualcomm Technologies’ best-in-class connectivity offerings with ST’s leading STM32 microcontroller ecosystem and will help drive a significant acceleration of feature-rich capabilities across the IoT. Together, we are setting new developer experiences for IoT applications, supporting seamless integration and optimal performance for developers and end-users alike.”

Focusing on the broader market, ST plans to introduce self-contained modules utilizing Qualcomm Technologies’ Wi-Fi/Bluetooth/Thread combo SoC portfolio, which can be system-level integrated with any STM32 general-purpose microcontrollers. Wireless connectivity optimized and made available to ST’s developer ecosystem through ST’s well established software platform will contribute to reducing development time and time-to-market. The initial product offerings resulting from this collaboration are expected to be available to OEMs in Q1 2025, with broader availability to follow. This is a first step in a collaboration that envisions a roadmap of Wi-Fi/Bluetooth/Thread combo SoC products over time, with the intention to extend into cellular connectivity for industrial IoT applications.

Andrew Zignani, Senior Research Director, ABI Research, commented “With the installed base of consumer, commercial and industrial connected devices expected to reach well over 80 billion units by 2028, the proliferation of high-performance wireless connectivity solutions combined with a diverse suite of microcontrollers will be fundamental in enabling this next wave of wireless IoT innovation. This collaboration between STMicroelectronics and Qualcomm Technologies is a perfect match thanks to ST’s leading microcontroller ecosystem and Qualcomm Technologies’ R&D leadership in wireless connectivity, and the growing availability of these combined solutions will enable companies to address this dynamic IoT market more simply, more quickly, and more cost-effectively in the years to come.”

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If you need a very pure sine wave in the audio range, the circuit in Figure 1 can help. It is a simple deal: A sine wave with a THD of 1% coming from a function generator that goes through a trackable low-pass filter, which attenuates the distortion-causing harmonics by a factor of 7900 (-78 dB) or more. The result is a sine wave with less than 0.0002% (2 ppm) distortion.

Figure 1 A frequency multiplier and a tracking low-pass filter reduce the THD of the sine signal coming from a function generator by 78 dB or more.

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

This implementation’s advantage comes from the fact that function generators provide two signals, a sine wave and a square wave, with the same frequency. The sine wave goes to the low-pass filter. A voltage divider reduces amplitude so that it does not exceed the input range of the filter. The switched-capacitor filter needs a clock signal with frequency that is 100 times larger than the frequency of the signal being filtered. The microcontroller–oscillator pair generates the clock signal. The microcontroller (µC) measures the frequency of the signal coming from the function generator, multiplies it by a factor of 100, creates a 16-bit control word, and sends it to the oscillator through an SPI interface. The oscillator generates a square-wave signal for the filter. The corner frequency of the filter equals the fundamental frequency of the input voltage.

Figure 2 and Figure 3 demonstrate the circuit operation with a 20-kHz triangular signal. Figure 2 shows the time domain signals from the function generator and at the output of the filter. Figure 3’s images are the spectrums of these signals. The filter passes the fundamental frequency and reduces the distortion-making harmonics down to the noise floor. The difference between the fundamental and the floor is about 50 dB, which is normal for the 8-bit ADC of the oscilloscope. More sophisticated (and more expensive) equipment is required to catch the difference of about 80 dB expected for the sine wave. Curious readers can get a sense of this business in references [1-4].

Figure 2 The time domain signals from the function generator and at the output of the filter.

Figure 3 The spectrum of the 20-kHz triangular signal: the fundamental harmonic is 50 dB above the noise floor. More sophisticated equipment is required for the sine wave.

It is worth mentioning that the same approach has been used to filter a square wave signal or a digitally generated sine wave with a very small number of stairs, see references [5-7]. Despite the large attenuation of the filter, the output signal is not a pure sine wave due to the high level of harmonics in the input signal: 43% for the square wave and 11-12% for a “sine” wave made of five stairs. The proposed circuit uses an input signal with 1% distortion (analog function generators) or 0.1% distortion (DDS-based function generators); hence the output signal will be at least 10 or 100 times cleaner than with the previous circuits.

If you decide to make the circuit, measure the period, not the frequency of the signal coming from the signal generator. The longest measurement time will be 50 ms instead of seconds.

Also, make sure you fill the period interval with at least 1000 clock pulses; the goal is to get 0.1% accuracy. This means clock rate of 20 MHz or more for the shortest period of 50 µs. Lower clock rates should be used for longer periods to avoid getting too large numbers for the captured clock pulses.

Finally, keep the sine signal amplitude from 3 to 9 VPP. This is the range where the filter provides minimum distortion and noise.

Jordan Dimitrov is an electrical engineer & PhD with 30 years of experience. Currently he teaches electrical and electronics courses at a Toronto community college.

Related Content

• Measure an amplifier’s THD without external filters
• Ultra-low distortion oscillator, part 2: the real deal
• A simple circuit with an optocoupler creates a “tube” sound
• Power Tips #116: How to reduce THD of a PFC
• Proper function linearizes a hot transistor anemometer with less than 0.2 % error
• RMS stands for: Remember, RMS measurements are slippery
• Precision synchronous detection amplifier facilitates low voltage measurements

 References

1. Williams J., G. Hoover. Test 18-bit ADCs with an ultrapure sine-wave oscillator. EDN, Aug. 11, 2011, 19-23.
2. Janasek V. An ultra low-distortion oscillator with THD below -140 dB. http://www.janascard.cz/aj_Download.html
3. ARTA software https://artalabs.hr/index.htm
4. TSP #234 – QuantAsylum QA403 24-bit, 0.0001% THD Audio Analyzer Review, Teardown & Experiments https://www.youtube.com/watch?v=BlWzpMkX5QQ
5. Horowitz P., W. Hill. The art of electronics. 3rd, 2015, pg. 436.
6. Saab A. Locked-sync sine generator covers three decades with low distortion. EDN, Sep 18, 2008.
7. Elliot R. Sinewave oscillators, Section 8 – Digital generation. https://sound-au.com/articles/sinewave.htm#s8

The post Getting an audio signal with a THD < 0.0002% made easy appeared first on EDN.