Thursday, January 23, 2020

Energy consumption is a hot topic in the world of voice-enabled AIoT devices. With good reason.

Mark Lippett, XMOS, January 23, 2020

Voice shows the fastest adoption of any consumer technology ever. At the current rate of growth, there’ll be a further 1.5 billion new voice-enabled devices in our homes in 2025, with an estimated 5 billion units in use worldwide.

Imagine all these devices powered up and hanging on to our every keyword. At a very rough estimate, those devices will consume 65 TeraWatt hours of electricity a year, simply by being always on, listening for a keyword. That’s almost the equivalent (90%) of the annual output of the world’s largest nuclear power plant. It’s not sustainable. Intelligent IoT systems should enable us to consume less, not more. 

As voice becomes a mainstream requirement and the focus moves inexorably forward to contextual, conversational interfaces, so we’re also seeing a shift in the semiconductor industry, with increasing innovation (and demand) around energy efficient solutions.

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Tuesday, January 7, 2020

Non-Linear Transmission Line Comb Generators Part-1: The Phase Noise Problem and Comb Generation

MACOM, January 07, 2020

In this two-part series from MACOM, we will delve into Non-Linear Transmission Line (NLTL) Comb Generators, first understanding the phase noise problem, and understanding a potential solution to the problem. In the second part of the blog series, we will explore NLTL comb generation, compare it to its predecessor comb generation using Step Recovery Diodes and see how the NLTL comb generation approach can enable improved sensitivity and lower bit error rates in communication systems.


Figure 1: Typical Superheterodyne Receiver
The Phase Noise Problem

Let’s start with the problem with circuits requiring low noise performance. Below we see a block diagram of the RF and IF portions of a typical superheterodyne receiver.  A weak signal is received at the antenna – 1) optionally amplified by a low noise amplifier, 2) filtered to reduce the effects of broadband noise and interferer signals whose frequencies may be close to that of the desired signal and then 3) downconverted to a lower, intermediate frequency for further processing. 

In the ideal case, the downconverter mixer mixes the received signal with a single-frequency local oscillator signal.  In the real case though, the local oscillator signal never comprises a single frequency, but is always accompanied by close-in noise sidebands which are generated in the local oscillator signal chain.  Also, the received signal may be accompanied by close-in interfering signals which cannot be completely removed by the band pass filter.

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Wednesday, June 12, 2019

How Wireless RF and Microwaves Affect the World Around You

Jaime Jones, NuWaves Engineering, June 12, 2019

Radio wave applications have come a long way since it was first theorized by James Clark Maxwell in his 1873 work “A Treatise on Electricity and Magnetism”, where he laid out mathematical theories showing the potential applications of radio technology. Only fifteen years later, German Physicist Heinrich Hertz became the first person to produce, transmit, and receive electromagnetic waves. At the time, Hertz considered his discoveries to have no practical use, going as far as to say “It’s of no use whatsoever”. One hundred and thirty-one years later, we now know the profound advancement RF and Microwave designs have made across the globe; including some ways you might not have even thought about.

Today nearly all people are interconnected wirelessly, and this evolution has transformed nearly all aspects of our lives. Learning, teaching, communicating, entertainment, healthcare – every industry has been sculpted around wireless RF technologies. Today, all of human knowledge and history rests in the palm of our hands, transmitted via an internet connection from a satellite orbiting one hundred miles above our heads. The depth doesn’t stop there though – each individual satellite must communicate with one another as well as the main controller on the ground. None of this would be possible without the usage of radio wave technologies. Not all uses of wireless RF devices are as grand, though. Conservationists in Africa use radio telemetry to track endangered species in their vast habitats. Hospitals utilize wireless RF to track hundreds of patients’ vital signs at once to allow for faster reaction times when it’s most needed.

Our world has forever been shaped by the pioneering into radio frequencies of the scientists, inventors, and engineers that came before us.

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Tuesday, October 23, 2018

The Health and Economical Benefits of Solid-State Cooking

MACOM, October 23, 2018

RFE Diagram.PNGThe ability to generate and amplify RF signals is nothing new – but solid-state RF energy has enormous potential beyond data transmission applications. As companies like MACOM and collaborative organizations such as the RF Energy Alliance (RFEA) continue to pioneer and develop this technology, enabling greater efficiency and control than previously possible with conventional technologies, the full potential of this technology for mass-market applications is beginning to take form.

Microwave cooking is one application that is already being radically transformed with solid-state RF energy, enabling healthier eating and broad economical benefits. Solid-state RF energy transistors generate hyper-accurate, controlled energy fields that are extremely responsive to the controller, resulting in optimal and precise use and distribution of RF energy. This offers benefits unavailable via alternate solutions, including lower-voltage drive, high efficiency, semiconductor-type reliability, a smaller form factor and a solid-state electronics footprint. Perhaps the most compelling benefit is the power-agility and hyper-precision enabled by this technology, yielding even energy distribution, unprecedented process control range and fast adaption to changing load conditions, not to mention a lifespan of more than 10 years.

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Thursday, September 13, 2018

Giving voice to the elderly

XMOS, September 13, 2018

Voice-enabled technologies will transform the health and happiness of the elderly.

The UN predicts a 56% rise in the number of people aged 60 years or over, taking us from over 900 million in 2015 to nearly 1.5 billion in 2030.The world’s population is changing. Our demographic is aging. And this could well be the defining issue of our time. An aging population creates a burden on health systems and individual households. Family members, clinicians, and assisted care providers will need a new generation of technology platforms to help them stay informed, coordinated, and most importantly, connected.

The social care system is facing a mountain of challenges and it can’t cope with a sustained upswing in the number of senior people and adults living with chronic illnesses.

Whether living at home or in an assisted facility, help may come from an unexpected source – technology. Speech recognition and voice-enabled devices make technology accessible to all. There’s no need to tap a keyboard or figure out how to work the remote control, you simply talk to the device from across the room. A voice-controlled device can empower a formerly ‘dis-empowered’ user. It can ease pressure on caregivers, becoming a companion and digital assistant. Of course it’s not a replacement for human interaction, but rather a meaningful addition.

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Thursday, June 21, 2018

Why 50 Ohms?

Ryan Foster, NuWaves Engineering, June 21, 2018

A common concern for radio frequency design engineers is providing sufficient margin in a module or system to survive the real-world application in which their work will eventually operate. Our engineering team is constantly dealing with the trade-offs of meeting the myriad of customer specifications while ensuring that our designs are robust enough to survive the unpredictable reality of fielding those designs. For instance, it is one thing to design an amplifier that operates in the perfectly controlled environment of a laboratory, but then connect that amplifier to an antenna which looks like a nice comfortable perch to a bird and you have a completely different story. One of the measuring sticks that engineers utilize to judge a system or modules robustness is to test is ability to survive a mis-matched load. Voltage Standing Wave Ratio (VSWR) is the most common method for quantifying the ability of a 50-ohm matched module to withstand the mis-matches that we all know it will experience when it is eventually fielded, with an output VSWR rating of 10:1 being common in the industry. But wait, where did that 50-ohms starting point come from?

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Monday, April 9, 2018

Common Mode Overview and Reduction Guide

MTE, April 9, 2018

Understanding the creation, effects, and how to reduce common mode over voltage.

What is Common Mode?

To start off, common mode is bad. Common mode voltage is created by Variable Frequency Drives (VFDs) that serve as a way of controlling the speed of AC motors by varying the frequency of the power source using pulse width modulation (PWM). This is done by switching the transistors, IGBTs, or thyristors, on and off continuously.

The continuous generation of power pulses from VFDs prevents a smooth sinewave from being produced, which at any point is at a sum of zero (see Fig.1). Instead, the waveforms produced result in a sum at any point that is not always zero (see Fig.2). The result is damaging common mode over voltage, which can cause devastating effects to your equipment.

Destructive Effects of Common Mode Over Voltage

Common mode problems occur outside of the VFD, which is why they are difficult to diagnose.  The effects of common mode over voltage are extremely problematic for everyday operations. These problems negatively effect your bottom line, creating the need to replace equipment, increase repair costs, and can result in the loss of production.

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