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Foundations for PLL Nonlinear Analysis: Modeling the Phase Detector and VCO

Foundations for PLL Nonlinear Analysis: Modeling the Phase Detector and VCO

The phase-locked loop (PLL) is widely used in contemporary analog and digital communication systems. In this article, we develop a nonlinear model for the analog PLL by analyzing its key components.


Exploring the Relationship Between FM Wave Bandwidth and the Modulation Index

Exploring the Relationship Between FM Wave Bandwidth and the Modulation Index

In this article, we'll investigate how varying the amplitude and frequency of the modulating tone impacts the bandwidth of FM signals. We'll also compare the modulation index in AM and FM schemes.


Exploring Bessel Functions: Understanding the Spectrum of Tone-Modulated FM

Exploring Bessel Functions: Understanding the Spectrum of Tone-Modulated FM

In this article, we’ll learn about the essential properties of Bessel functions and what they can tell us about the bandwidth of practical FM signals.


Introduction to Wideband FM Signals

Introduction to Wideband FM Signals

Learn how Bessel functions and the modulation index can help us understand the bandwidth of wideband frequency-modulated (FM) signals.


Dynamic Nonlinearity in RF Power Amplifiers: Insights From Two-Tone Testing

Dynamic Nonlinearity in RF Power Amplifiers: Insights From Two-Tone Testing

This article explores the effect of signal bandwidth on the linearity of power amplifiers, including the impacts of cascaded RF gain stages.


Practical Insights Into Narrowband FM With a Single-Frequency Input

Practical Insights Into Narrowband FM With a Single-Frequency Input

In this article, we’ll use phasor diagrams to compare narrowband FM and conventional AM. We’ll also discuss the problem of oscillator phase noise and work through an example problem.


Introduction to Narrowband Angle Modulation

Introduction to Narrowband Angle Modulation

Using a simple example, this article examines the frequency spectra of frequency-modulated (FM) and phase-modulated (PM) waves for a low modulation index.


Understanding the Differences Between Phase and Frequency Modulation

Understanding the Differences Between Phase and Frequency Modulation

Learn why phase modulation (PM) and frequency modulation (FM) can produce waveforms that are nearly identical or completely different from one another, depending on the nature of the message signal.


A Guide to Calculating IM3 and IP3 for Nonlinear RF Circuits

A Guide to Calculating IM3 and IP3 for Nonlinear RF Circuits

Learn to confidently determine intermodulation distortion products and the third-order intercept point of RF circuits by working through a selection of example problems.


Understanding Intermodulation Distortion and the Third-Order Intercept Point In RF Systems

Understanding Intermodulation Distortion and the Third-Order Intercept Point In RF Systems

Learn how the two-tone input test helps us evaluate the nonlinearity of RF systems operating on real-world signals.


Hands-ON With AT Commands: The LoRaWAN Trainer

Hands-ON With AT Commands: The LoRaWAN Trainer

We use a Raspberry Pi and free software to build a test platform for IoT systems.


Projects Mar 02, 2025 by Don Wilcher
Programming Your Standalone Hardware Soundboard

Programming Your Standalone Hardware Soundboard

In Part 2 of this two-part series, we turn our hardware assembly into a functioning soundboard by adding the necessary code in Arduino IDE and uploading soundbites.


Craft Your Own Hardware Soundboard Using an Arduino Microcontroller

Craft Your Own Hardware Soundboard Using an Arduino Microcontroller

Learn how to turn an ATmega328 microcontroller and an assortment of readily available parts into a dedicated hardware soundboard.


Understanding How Ring Modulators Produce AM Signals

Understanding How Ring Modulators Produce AM Signals

Among modulator circuits, the ring modulator stands out as one of the most effective for generating AM signals. Learn why in this article.


Introduction to Near-Field Probes and Their Use in EMC Troubleshooting

Introduction to Near-Field Probes and Their Use in EMC Troubleshooting

Learn about the working principles of near-field probes and their applications in troubleshooting EMI issues.


The BBC Micro:bit Adjustable Brightness Alarm: A Radio Shack Remix

The BBC Micro:bit Adjustable Brightness Alarm: A Radio Shack Remix

In this project article, we’ll create a programmable device that alerts users to changes in ambient light levels. Along the way, we’ll learn about astable multivibrators and the Darlington pair.


Projects Nov 20, 2024 by Don Wilcher
Introduction to Modulation Techniques in RF Systems

Introduction to Modulation Techniques in RF Systems

In this article, we discuss the basics of RF modulation and how it affects the performance of communication systems.


Building a Resistor Color Code Calculator and Ohmmeter Using Arduino

Building a Resistor Color Code Calculator and Ohmmeter Using Arduino

For this project, I built a handheld resistor color code calculator and ohmmeter using the ATmega328 microcontroller and a 1.8-inch color LCD display.


A Cortex-M Microcontroller-Enabled Electronic Timer: A Radio Shack Remix

A Cortex-M Microcontroller-Enabled Electronic Timer: A Radio Shack Remix

In this Radio Shack Classic Circuits Remix, we add modern microcontroller functionality to the vintage Electronic Timer project for the Science Fair 65-in-1 kit.


Projects Sep 15, 2024 by Don Wilcher
Broadcasting Custom Advertising Data on the nRF52 DK: A Bluetooth LE Tutorial

Broadcasting Custom Advertising Data on the nRF52 DK: A Bluetooth LE Tutorial

Learn how to turn an nRF52 development kit into a Bluetooth Low Energy beacon that broadcasts either static or dynamic custom data.