PLL and Frequency Synthesizer - Concept and Characterization (RF89-98-0)

SynopsisPhase-locked Loop (PLL) is widely used in telecommunications and other electronic applications for signal stability or recovery. When added with a programmable frequency divider and reference oscillator, PLL circuit will act as a frequency synthesizer.

This course aims to provide a good understanding of the PLL/Frequency Synthesizer circuit through a coverage of basic concepts, computer simulation, real-life implementation and circuit characterization using RF and analog instruments.

Course Highlight
For each of the topic covered, the students are first taught the basic concepts. The design technique and its practical implementation are then covered. Software tools such as Agilent ADS and MathCAD are used to enhance the learning process. Measurement of PLL module using Spectrum Analyzer, Signal Generator and Digital Sampling Oscilloscope will be carried out to illustrate the principles and techniques taught. The measurement will be carried out on a trainer board which can be configured as a PLL, or with programmable frequency dividers and crystal reference oscillator added to become a frequency synthesizer.

What previous participants say about this course
Answers to the question 'what did you like most about the course'

• "Hands-on and knowledgeable instructor" - 23 Dec 06
• "Practical lab and theory which is presented in effective way" - 23 Dec 06
• "Handson- using simulation tools & lab session" - 24 Jan 07 
• "The lab session and hands-on on circuit simulation & tweaking" - 24 Jan 07
• "Practical and simulation attached" - 24 Jan 07
• "Hands on for the lab experiments after completing the theory class is very helpful" - 28 May 07
• "ADC sampling clock, osaloscope time base generator" - 2 Jun 08
• "During troubleshooting especially in the concept and understanding of the PLL concept" - 2 Jun 08
• "Understand the PLL circuitry, aids in either troubleshooting or designing PLL / synthesizer based products" - 2 Jun 08

Figures below showing part of PLL System Trainer and instruments used in the training

What You Will Learn

• Basic Concepts of PLL
• Practical PLL Components
• Linear Mathematical Model of PLL
• Implementation and Measurement of PLL/Synthesizer Circuits
• Introduction to Frequency Synthesis using PLL

Who Should AttendEngineers and senior technicians who work with PLL and Frequency Synthesizer in the role of :

• design and development
• product engineering
• test development
• application engineering
• product marketing
• testing
• system architect

PrerequisiteGood understanding of analog and digital electronics fundamentals, for example the operation of diode, bipolar-junction transistor, operational amplifiers, logic gates, flip-flops and basic circuit theories. A basic understanding of feedback control theory will be helpful.

Course MethodologyFor each of the topic covered, the students are first taught the basic concepts. The design technique and its practical implementation are then covered. Software tools such as Agilent ADS and MathCAD are used to enhance the learning process.

Measurement of PLL module using Spectrum Analyzer, Signal Generator and Digital Sampling Oscilloscope will be carried out to illustrate the principles and techniques taught.

The measurement will be carried out on a trainer board which can be configured as a PLL, or with programmable frequency dividers and crystal reference oscillator added to become a frequency synthesizer.

Course Duration3 days, 9am - 5pm

Course StructureDay 1
Basic Concepts

• Signals, frequency and phase.
• Phase-locked loop (PLL) block diagram and history.
• PLL building blocks - Voltage controlled oscillator (VCO), Phase-Detector (PD), Loop Filter, Loop Amplifier.
• How PLL works: Operating modes - free-running, acquisition and tracking, and the meaning of phase-locked.
• Uses of PLL in telecommunication.

Practical PLL Components

• Phase Detector (PD) - Analog PD (mixer type), and digital PD (XOR gate), Phase-Frequency Detector (PFD) with charge-pump. Sample circuits will be shown.
• Voltage controlled oscillator - Negative resistance oscillator and relaxation oscillators.
• Loop filter and amplifier circuits.
• Lock range, capture range and static (steady-state) phase error.
• Demo - PLL modeling and simulation using ADS.
• Exercise - Static PLL analysis.

Day 2
Linear Mathematical Model of PLL

• Linear mathematical model of PLL under tracking mode.
• The feedback equations.
• Differentiating PLL by loop gain characteristics - Type I, Type II and higher-order PLL.
• Time-domain response of PLL under tracking mode.
• The importance of Loop Filter.
• Exercise - Analysis of PLL under tracking mode.

Demonstration and Measurement of PLL/Synthesizer Trainer Board

• Introduction to the PLL circuit with digital PD, printed circuit board layout and actual hardware.
• Measurement exercise

             1) Plotting VCO response
             2) Free running mode observation
             3) Acquisition mode observation
             4) Tracking mode observation
             5) Out-of-lock condition observation
             6) Tracking mode with step change in reference frequency observation (time-domain response)

• Discussion and Quiz.
• ADS modeling exercise.

Day 3
Introduction to Frequency Synthesis using PLL

• Frequency divider.
• Modification of a basic PLL system into a frequency synthesizer.
• Integer N frequency synthesizer.
• Frequency domain response - phase noise and spurs, external noise rejection.
• Time-domain response.
• Fractional N frequency synthesizer
• Miscellaneous - Modification of the basic integer N frequency synthesizer to include mixer, dual-loop architecture etc.

Demonstration and Measurement of PLL/Synthesizer Trainer Board

• Introduction to the frequency synthesizer circuit, printed circuit board layout and actual hardware.
• Basic synthesizer measurement: frequency stability, amplitude stability, phase noise, spurs, resolution, range etc.
• Dynamic response measurements: switching from one frequency to another, between adjacent frequency channels and between frequency channels far apart.
• Discussion and Quiz.
• ADS modeling exercise.