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Understanding Linear-Phase Filters

Understanding Linear-Phase Filters

Linear phase response, also known as constant group delay, is an important property in some filter applications.


Understanding Complex-Conjugate Poles in Filter Theory

Understanding Complex-Conjugate Poles in Filter Theory

This technical brief explains the importance of complex-conjugate poles and second-order stages in optimizing filter performance.


The CMOS Transmission Gate

The CMOS Transmission Gate

This technical brief presents a simple MOSFET configuration that can be used as a voltage-controlled switch.


MOSFET Channel-Length Modulation

MOSFET Channel-Length Modulation

This technical brief describes channel-length modulation and how it affects MOSFET current–voltage characteristics.


Signal Conditioning for Pyroelectric Passive Infrared (PIR) Sensors

Signal Conditioning for Pyroelectric Passive Infrared (PIR) Sensors

Learn about the basics, signal conditioning, digital output, and hardware specs of passive infrared sensors.


Understanding the Delta-Sigma ADC

Understanding the Delta-Sigma ADC

ADCs (analog-to-digital converters) can be described as either Nyquist-rate or oversampled converters. The Delta-Sigma ADC belongs to the oversampled family of converters. It relies upon oversampling and noise shaping to achieve high-resolution conversions.


The Actively Loaded MOSFET Differential Pair: Measuring Lambda, Predicting Gain

The Actively Loaded MOSFET Differential Pair: Measuring Lambda, Predicting Gain

In this article, we’ll look at the equation for differential gain and use LTspice to find the value of the channel-length-modulation parameter referred to as lambda (λ).


The Actively Loaded MOSFET Differential Pair: Output Resistance

The Actively Loaded MOSFET Differential Pair: Output Resistance

In this article, we’ll discuss MOSFET small-signal output resistance as we make our way toward predicting the gain of the actively loaded differential pair.


Understanding Arduino UNO Hardware Design

Understanding Arduino UNO Hardware Design

This article explains how Arduino works from an electronic design perspective. It also explains the role of every part of the Arduino.


The Basic MOSFET Constant-Current Source

The Basic MOSFET Constant-Current Source

Learn about a straightforward version of a circuit that is essential in the design of analog integrated circuits.


Circuits and Techniques for Implementing Capacitive Touch Sensing

Circuits and Techniques for Implementing Capacitive Touch Sensing

This article presents some basic cap-sense circuit configurations and discusses how to deal with low- and high-frequency noise.


Inductor Out, Op-Amp In: An Introduction to Second-Order Active Filters

Inductor Out, Op-Amp In: An Introduction to Second-Order Active Filters

In this article, we’ll compare active and passive filters and look at some common second-order active topologies.


FIR Filter Design by Windowing: Concepts and the Rectangular Window

FIR Filter Design by Windowing: Concepts and the Rectangular Window

In this article, we'll review the basic concepts in digital filter design. We'll also briefly discuss the advantages of FIR filters over IIR designs, e.g. stability and linear-phase response. Finally, we'll go over an introduction to designing FIR filters via the window method.


Digital-to-Analog Conversion with the SAM4S Peripheral DMA Controller

Digital-to-Analog Conversion with the SAM4S Peripheral DMA Controller

Part Three in this three-article series shows you how to generate values for a discrete sinusoid and continuously convert this data into an analog signal without overburdening the CPU.


Projects May 09, 2016 by Robert Keim
Understanding and Using the SAM4S Digital-to-Analog Converter

Understanding and Using the SAM4S Digital-to-Analog Converter

Part Two in this three-article series explores the SAM4S DAC. We’ll look at hardware configuration, electrical characteristics, and the application programming interface.


Projects May 04, 2016 by Robert Keim
DMA Digital-to-Analog Conversion with a SAM4S Microcontroller: The Timer/Counter

DMA Digital-to-Analog Conversion with a SAM4S Microcontroller: The Timer/Counter

Part One in this three-article series focuses on using the SAM4S timer/counter peripheral to precisely control the DAC’s sampling rate.


Projects Apr 28, 2016 by Robert Keim
PWM Digital-to-Analog Conversion with the SAM4S Xplained Pro

PWM Digital-to-Analog Conversion with the SAM4S Xplained Pro

In this article we’ll use the SAM4S Xplained Pro development platform to get some hands-on experience with a PWM DAC.


Projects Apr 19, 2016 by Robert Keim
Low-Pass Filter a PWM Signal into an Analog Voltage

Low-Pass Filter a PWM Signal into an Analog Voltage

In this article we will take a closer look at how to effectively low-pass filter a PWM signal into an analog voltage.


Turn Your PWM into a DAC

Turn Your PWM into a DAC

If your microcontroller doesn’t have a digital-to-analog converter, you can make a passable replacement with nothing more than a pulse-width-modulated signal and a low-pass filter.


Building Raspberry Pi Controllers Part 5: Reading Analog Data with an RPi

Building Raspberry Pi Controllers Part 5: Reading Analog Data with an RPi

Learn how to read electrical signals and data from an analog device using the Step Response technique in Part 5 of the Building Raspberry Pi Controllers series.


Projects Feb 09, 2016 by Don Wilcher