Synchronization in Digital Communication By: Bader Al-Kandari and Josh Mason Advisors: Dr. Thomas L. Stewart, Dr. In Soo Ahn

Project Design Review Contents  Project Summary  Functional Description  Transmitter/Receiver Block Diagrams  Hardware/Software  Preliminary Results  Original Work Schedule  Work Completed  Revised Work Schedule  Questions?

The purpose of this project is the development of a Quadrature Amplitude Modulation (QAM) signal communication system in order to test synchronization methods of digital communication systems.

Functional Description

 Inputs TransmitterTransmitter  Signals from a function generator  Stored Data ReceiverReceiver  QAM signal  Stored Data

Functional Description  Outputs TransmitterTransmitter  QAM signal ReceiverReceiver  Recovered Data  Matlab/Simulink Data Acquisition

Functional Description  Modes of Operation Transmitter – Real Time Modulation Receiver – Real Time Demodulation

Transmitter Block Diagram

Transmitter Block Diagram Transmitter Block Diagram

Transmitter Block Diagram

 Adaptable for stored data inputs  Differential Coding  Possibility of M-Level QAM

Receiver Block Diagram

Hardware/Software  TI c6713 DSP 8 KHz, 32 KHz, 44.1 KHz, 48 KHz, and 96 KHz8 KHz, 32 KHz, 44.1 KHz, 48 KHz, and 96 KHz  Matlab/Simulink  Code Composer Studio

Preliminary Results  QAM Simulink Development 4-QAM Transmit/Receive4-QAM Transmit/Receive  DSP interfacing/testing Digital filteringDigital filtering  Analog source  Data Source

Original Schedule PracticalTheoretical 12/1/2005Proposal PresentationProposal Presentation Winter BreakWork on WebsiteWork on Phase distortion 1/24/2006Fully Develop DSP I/O correction 1/31/2006w/ Matlab/Simulink 1/31/2006w/ Matlab/Simulink 2/7/2006Begin Documentation 2/7/2006Begin Documentation 2/14/2006Test/gather data ofFinalize 4-QAM 2/21/2006implemented 4-QAM 2/21/2006implemented 4-QAM 2/28/2006Documentation/TutorialFinish up any remaining 3/7/2006Workphase distortion problems 3/21/20068-QAM testing/data 3/21/20068-QAM testing/data 3/28/2006gatheringBegin work on 8-QAM 4/4/2006Documentation/Tutorialand 16-QAM 4/11/ QAM testing 4/11/ QAM testing 4/18/2006DocumentationDocumentation 4/25/2006PresentationPresentation 5/2/2006

Tasks Completed  RTDX Testing  Phase Tracking using Phase Lock Loop

RTDX Testing  Success Using m-files  Unable to succeed using block diagram modeling

RTDX Testing (m-file)  M-file has RTDX input channel and output channel  Increments the values of an array passed into the input channel  Program then reads the output channel  Literally runs on DSP

RTDX Testing (m-file)  [ ]

RTDX Testing (m-file)

RTDX Testing (Block Diagram)

PLL Subsystems  Phase Detector (PD)  Loop Filter (LF)  Oscillator [1]Voltage Controlled (VCO) [1]Voltage Controlled (VCO) [2]Direct Digital Synthesizer (DDS) [2]Direct Digital Synthesizer (DDS)

PD Implementation

PD models Inverse tangent model “Cross product terms” (CPT) model

Comparison Atan2 PD CPT PD

Loop Filter

Design equations for LF

LF  Loop filter is PI integrator  Why?  y(n) = y(n-1) + k1*x(n) + k2*x(n-1)

DDS

DDS Simulation Frequency = 40 Hz

Complete model

Model on 6713

Simulation parameters and specs  Input frequency = 42 Hz  LF natural frequency = 5 Hz  DDS running frequency = 40 Hz  Fs = 8000 Hz

Simulation results

Laboratory results

Phase error

Filter output at 41 Hz

What’s Left  Differential Coding  2-D Slicer  Automatic Gain Control  Symbol Timing  RTDX or Comparative Method

Revised Project Schedule Bader Al-KandariJosh Mason 3/7/2006Fully Debug PLL + DocumentRTDX + Document BreakResearch Symbol TimingResearch Diff Coding 3/21/2006Symbol TimingDifferential Coding 3/28/2006Symbol TimingDifferential Coding 4/4/20062-D SlicerDiffCoding/Prepare for Student EXPO 4/11/20062-D SlicerData Preparations 4/18/2006Automatic Gain Control 4/25/2006Documentation 5/2/2006Presentation

Questions? != 45

Inverse tan PD

Atan2 simulation results

Lab results