DESIGN AND SIMULATION OF PLL & DLL USING MATLAB SIMULINK

MADE BY :- KARTIK PAL

(131029)

PHASE LOCKED LOOP (PLL)

INTRODUCTION

What is a PLL? Block Diagram of PLL Parts of a PLL PLL Design in Simulink

• PLL Without divider design• Waveform• PLL With divider design• Waveform

What is a PLL? A phase lock loop (PLL) is a control

system that generates an output signal whose phase is related to the phase of an input signal

Block Diagram

Parts of a PLL Phase Detector Filter Voltage Controlled Oscillator Programmable Counter/Divider

Parts of a PLL Phase Detector

Acts as comparator Produces a voltage proportional to the phase

difference between input and output signal Voltage becomes a control signal

Parts of a PLL Filter

Determines dynamic characteristics of PLL Specify Capture Range (bandwidth) Specify Tracking Range

Receives signal from Phase Detector and filters accordingly

Parts of a PLL Voltage Controlled Oscillator

Set tuning range Set noise margin Creates low noise clock oscillation

Divider Divides the VCO output by the degree of the open

loop gain Feedback loop allows phase comparison

Parts of a PLL

PLL Design in SimulinkPLL Without Divider design

WaveformInput signal

Phase Detector

Control signal

Synthesized Signal

Spectrum Analyser

PLL With Divider Design

WaveformInput signal

Phase Detector

Control signal

Synthesized Signal

Spectrum Analyser 1

DELAY LOCKED LOOP (DLL)

INTRODUCTION What is a DLL? Block Diagram of DLL Parts of a DLL DLL Design in Simulink

• DLL design• Waveform

What is DLL?

A delay-locked loop (DLL) is a digital circuit similar to a Phase-Locked Loop (PLL), with the main difference being the absence of an internal  voltage-controlled oscillator(VCO), replaced by a voltage-controlled delay line (VCDL).

Block Diagram

Parts of a PLL Phase Detector(PD) Charge pump(CP) Loop Filter(LF) Voltage Controlled Delay Line(VCDL)

Parts of a DLL Phase Detector(PD)

Acts as comparator Produces a voltage proportional to the phase

difference between input and output signal Voltage becomes a control signal

Parts of a DLL Charge Pump(CP)

• The outputs of the PD are directly connected to the inputs of CP, and CP prepares the input of LF which is proportional to the width of the PD output signals (inputs of CP).

• In Matlab Simulink, a simple adder can be used to model CP

Parts of a DLL Loop Filter(LF)

• Loop filter is a simple integrator that performs integral of the output signals from CP.

• In the other word the loop filter’s capacitor gets charged or discharged if there is a time lead or time lag between the reference signal and the output of the delay line.

Parts of a DLLVoltage Controlled Delay Line(VCDL)

• Voltage controlled delay line (VCDL) includes a chain of delay cells.

• Usually all of the delay cells have the same structure.

• In locked condition, the output of the last delay stage is exactly one cycle lagged from the reference clock (Vin).

DLL Design in Simulink

WaveformInput signal & Output signal