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Evaluating the Noise Performance of Coherent DSB‑SC Demodulators

Evaluating the Noise Performance of Coherent DSB‑SC Demodulators

In this article, we'll learn how to calculate the noise power and signal-to-noise ratio (SNR) of a double-sideband suppressed-carrier communication system.


Understanding the Characteristics of Narrowband Noise in Communication Systems

Understanding the Characteristics of Narrowband Noise in Communication Systems

In this article, we analyze how bandpass filtering affects the power spectral density (PSD) of noise and explore how noise can be described by in-phase and quadrature components.


From Tracking Filters to Demodulation: Exploring the Applications of PLLs

From Tracking Filters to Demodulation: Exploring the Applications of PLLs

In this article, we'll learn about several key applications of PLLs in communication systems, including tracking filters, frequency and phase modulation, and FM and AM demodulation.


Introduction to Phase/Frequency Detectors

Introduction to Phase/Frequency Detectors

Learn how using a phase/frequency detector (PFD) in place of a phase detector improves the acquisition range of a PLL.


Introduction to the RS Flip-Flop Phase Detector

Introduction to the RS Flip-Flop Phase Detector

Learn about this simple sequential phase detector and how it compares to the XOR gate. We'll also examine some key limitations and circuit implementations.


Diode-Based Phase Detectors: Key Principles and Example Circuits

Diode-Based Phase Detectors: Key Principles and Example Circuits

We examine phase detectors that leverage either the nonlinear characteristics or switching capabilities of diodes to perform multiplication.


Using Gilbert Multipliers as Phase Detectors in PLLs

Using Gilbert Multipliers as Phase Detectors in PLLs

This article explores the operation of the Gilbert-cell phase detector for both small and large signals.


Introduction to the Gilbert Multiplier

Introduction to the Gilbert Multiplier

This article explores the Gilbert cell, a widely used analog multiplier circuit.


Second-Order Type-2 PLLs: Bode Diagrams, Bandwidth, and Overshoot

Second-Order Type-2 PLLs: Bode Diagrams, Bandwidth, and Overshoot

Learn how to select the zero frequency, damping factor, and loop bandwidth for one of the most popular PLL configurations.


Introduction to Second-Order Type-2 PLLs

Introduction to Second-Order Type-2 PLLs

This article explains how Type-2 PLLs with an integrator loop filter outperform Type-1 systems. To do so, we'll examine the PLL behavior for frequency step and frequency ramp inputs.


Analyzing the Lag Filter’s Effect on PLL Performance

Analyzing the Lag Filter’s Effect on PLL Performance

In this article, we evaluate the designs of two simple frequency synthesizers to learn how a second-order PLL with a lag filter can provide a faster rise time than a first-order PLL.


Understanding the Limitations of the First-Order PLL

Understanding the Limitations of the First-Order PLL

Higher-order PLLs are more commonly used than first-order PLLs. To explain why, we explore the first-order PLL's behavior in response to two inputs: a frequency step and frequency ramp.


Analyzing First-Order PLLs Using Linear Models

Analyzing First-Order PLLs Using Linear Models

In this article, we'll use the linearized model of a first-order PLL to understand its response to a simple input change. We'll then use Matlab simulations to visualize the signals.


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.


FM Demodulation Using a Phase-Locked Loop

FM Demodulation Using a Phase-Locked Loop

PLL demodulators are popular, easy to implement, and offer superior noise performance compared to many other FM demodulator circuits. Learn how they operate in this article.


Basic Principles and Implementation of the Quadrature FM Demodulator

Basic Principles and Implementation of the Quadrature FM Demodulator

Learn how an analog multiplier or AND gate can function as a quadrature detector for FM demodulation.


FM-to-AM Conversion Using the Foster-Seeley Discriminator

FM-to-AM Conversion Using the Foster-Seeley Discriminator

Learn how the Foster-Seeley discriminator, a classic analog circuit for FM demodulation, achieves its superior linearity.


Understanding Slope Detectors for FM Demodulation

Understanding Slope Detectors for FM Demodulation

In this article, we'll analyze the single-tuned discriminator for FM-to-AM conversion. We'll then discuss the balanced discriminator and how it provides improved linearity across a wider bandwidth.


Introduction to Frequency Discriminators for FM Demodulation

Introduction to Frequency Discriminators for FM Demodulation

In this article, we will examine the basic principles of FM demodulation through the simplest frequency discriminator: a differentiator.


FM Generation Techniques: Solved Examples

FM Generation Techniques: Solved Examples

In this article, we'll solidify our understanding of the reactance modulator and Armstrong modulator circuits by working through a series of design problems.