Applications Telephone systems Tele-Banking Electronic

1
Dual Tone Multi-Frequency DetectionUsing
Digital Signal ProcessorTMS320C5416

• Project Guides Project
  Team
  
• Prof. S.B.Jain Neha Gupta
  (22/ECE/2k1)
• Mr. Akash Tayal Shalini Lal
  (41/ECE/2k1)
• Ms. Priyanka Jain
• Electronics and Communication Department
• Indira Gandhi Institute Of Technology

2
Presentation Contents

• Project Introduction
• Digital Signal Processors
• TMS320C5416
• Code Composer Studio IDE
• Project Description
• Project Implementation
• Applications
• Project timeline
• References

3
Project Introduction

• Software implementation of
• Dual Tone Multi-Frequency Detection Algorithm
  using
• Digital Signal Processor TMS320C5416
• and
• interfacing the required hardware for
• DTMF Generation and Detection

4
Digital Signal Processors

• Special-purpose Central Processing Unit
• Real Time Processing
• Perform speedy calculations
• Math-intensive Arithmetic and Logic Unit
• Programmable and Scalable
• Based on Harvard Architecture

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Harvard Architecture
6
Advantages of DSPs

• Flexibility
• Easier Upgradeability
• Easy Data Storage and Access
• Better control over accuracy
• Scalability

7
TMS320C5416

• Operating frequency 16-160Mhz
• 5 Volt Operation
• On board USB JTAG controller with plug and play
  drivers
• PCM Stereo Codec
• High-performance and power efficiency
• 16-bit, Fixed-point processor
• Cache for speedy fetching process
• Fully static device.
• Full-static CMOS design contributes to low
  power consumption while maintaining high
  performance, making it ideal for applications
  such as battery-operated communications systems,
  satellite systems, and advanced control
  algorithms.

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Functional Block Diagram of TMS320C5416

• 64K words of on board RAM
• 256K words of on board Flash ROM
• 3 Expansion Connectors
• Memory Interface
• Peripheral Interface
• Host Port Interface

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Special features of TMS320C5416

• Low-cost versatile development tool
• 5426DSK Diagnostics
• Integrated Development Environment
• Code Composer Studio(DSK5416)
• Optional add-on modules like LCD, Keypad, CODEC
• and ADC/DAC interfaces
• DSK Starter kit
• TMS320C5416 Kit consists of
• C5416 DSK Board
• 5V Universal Power Supply
• AC Power Cord
• USB Cable
• C5416 DSK Code Composer Studio CD ROM
• DSK Technical Reference

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Code Composer Studio IDE

• Highly advanced C Compiler and assembly optimizer
• Real Time Analysis with RTDX and DSP/BIOS
• Advanced data visualization
• Statistics Accumulation Display
• User-Defined Event Log
• System Event Log
• Graphical Execution Log
• CPU Load Display

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Code Composer Studio IDE
.asm/ .c
.obj
Assembler/ Compiler
Editor
Linker
.exe
.out
DSK C5416
Loader
EPROM Programmer
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Dual Tone Multi Frequency

• DTMF is an international signaling standard for
  touch-
• tone telephones.
• DTMF signaling uses voice band tones to send
  address
• signals and other digital information from
  push-button
• telephones.
• DTMF generator generates standard telephone
  digits as
• the sum of sinusoids of predefined set of
  frequencies.
• These frequencies should be generated and
  detected
• according to the CCITT Recommendation.

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Dual Tone Multi-Frequency
Frequencies 1209Hz 1336Hz 1477Hz 1633HZ
3
2
1
A
697Hz 770Hz 852Hz 941Hz
4
5
6
B
7
8
9
C

0

D
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Dual Tone Multi Frequency

• DTMF is based on Discrete Fourier Transform.
• DTMF Decoder takes a digital signal as input
  signal and decodes into a digit.
• Digital DTMF Detection overcomes many drawbacks
  of using Analog devices
• Cost of hardware
• Distortion and Noise affecting signaling
  information
• Need of D/A Converters.
• Reliability

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Dual Tone Multi FrequencyTouch Tone Dialing

• DTMF System consists of three modules
• Generator
• Estimation using decoder
• Detector

Generator
Decoder
Detector
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DTMF Generator

• DTMF (Touch Tone ) Keypad for a digit entry as a
  D/A converter
• Each digit corresponds to two sinusoidal
  frequencies from two mutually exclusive groups
• Two programmable second order digital sinusoidal
  oscillators
• One for the row and the other for column tone
  frequencies
• Sampling frequency 8Khz.
• Superposition of two sinusoids is transmitted as
  DTMF signal

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DTMF Decoder Goertzels Algorithm

• Software Detection of DTMF signals in digital
  domain.
• It is a filter bank implementation .
• It is a second-order filter that extracts the
  energy present at a specific frequency.
• Frequency Detection by computing Discrete
  Fourier Transform (DFT) samples close to the 8
  fundamental tones.
• Computation of the DFT as a linear filtering
  operation.
• Effective and fast way to extract spectral
  information from an input signal.

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Why use Goertzels Algorithm?

• Real time processing as it processes input data
  as it arrives being a recursive structure.
• Goertzels algorithm reduces the data memory
  required significantly.
• Requires limited processing.
•  Best approach for smaller sequence lengths.
• Best computational load and memory usage
  efficiency.

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Goertzels Algorithm Implementation
s(n)


Xn
Yn
z-1
s(n-1)
a
-Wn


z-1
s(n-2)
-1

• The recursive calculation of the DFT
  coefficient is
• yk(n) s(n) WNk s(n-1)
• where s(n) and s(n-1) represent the value of
  the state variables at times n and
• n-1.
• It can be shown that after N samples
• yk(N)2 s(N)2 - 2cos(2?k/N) s(N)
  s(N-1) s(N-1)2
• yk(N)2 is a measure of the squared power of
  the test frequency in the input signal.

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DTMF Detector

• Detect DTMF tones in an incoming signal and
  convert them into actual digits.
• It is a continuous process, i.e. it needs to
  search an ongoing incoming data stream for the
  presence of DTMF tones continually.
• The general approach taken for DTMF tone
  detection is to take the Fourier transform of the
  observed signal and search for energy at the
  frequencies of interest.
• Decoding a DTMF signal involves
• Extracting the two tones in the signal
• Determining from their value the intended DTMF
  digit.

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DTMF Detector Requisites

• Hardware Requirements
• DSK 5416 board with on-chip RAM and ROM,
  LEDs, DIP switches USB cable loud speakers
  microphone, touch-tone keypad amplifier
  transformer and rectifier circuitry.
• Software requirements
• Code Composer Studio IDE of TMS320C5416.
• Dual Tone multi-frequency generation
• Inputting the tones generated form a touch
  tone keypad into a microphone connected to the
  DSK 5416 port Mic In.
• Dual Tone multi-frequency detection
• Decoding the DTMF Tones using Goertzels
  Algorithm and sending them into Loud Speakers
  Audio Out.

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DTMF Implementation

• bargraph.c configures four on-board LEDs as a
  bargraph display.
• goertzel_algorithm.c calculates goertzel value
  and output power for a single frequency for all
  the keypad digits.
• goertzel.c uses the goertzel_algorithm to
  identify the dialed tones of the keypad and
  samples it at 8 KHz and sends the output to the
  loudspeaker.
• stereo.c sends the detected tone to loudspeaker.
• switches.c selects goertzel filters using the
  four DIP switches.
• bargraph.h declares bargraph functions and
  spectral display functions.
• goertzel.h initializes frequency for each tone
  along with goerzel filter declaration.
• stereo.h stereo functions declaration
• switches.h initializing DIP switches
• goertzel.cdb setting the configuration of DSP
  for the application.

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Functional Overview of the project
Digit 1 pressed
Digit 1 decoded
DTMF Detection
DTMF Generation
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Architectural View
AC Power Supply
5V Adapter
Audio In
DSK 5416
Microphone
Amplifier
Audio Out
Speaker
Telephone Line In
LEDs
s/w
L
R
Loud Speakers
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DTMF Applications

• Telephone systems
• Tele-Banking
• Electronic mail system
• Voice mail system control
• Remote operation
• Home Automation

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Project Timeline
a b c d e
f g h
i

• Project Search through various sites, books and
  IEEE papers
• Project Introduction Presentation and study
  commencement
• Architectural study of TMS320C5416 and DTMF
  application study
• Working Procedure study of Code Composer Studio
  IDE
• Working out small applications over TMS320C5416
  kit
• Implementing Goertzels DTMF Detection Algorithm
• Study of interfacing Touch pad for tone
  generation and speaker for tone detection
• Implementation of the interfacing peripherals
• Project Submission

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References

• Web links
• www.ti.com
• www.mathworks.com
• www.dspuniversity.com
• Books
• Digital Signal Processing and Applications by
  Rulph Chassaing.
• Digital Signal Processing by Manolakis, Dimitris
  G. and John G. Proakis. Macmillan Publishing Co.
• Digital Signal Processing by S.K.Mitra.
• Digital Signal Processing by Oppenheim, Alan V.
  and Schafer, Ronald W. Prentice-Hall of India.

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References

• Research Papers
• DFT based DTMF Detection Algorithm J.H.Beard,
  S.P.Given, B.J.Young, Pages 59-63.
• Providing Touch-Tone Services over Voice over
  packet networks-
• Julian Penketh,Nortel Networks, Pages 1-3.
• Performance Analysis of Goertzels algorithm
  based DTMF Detection schemes- M.K.Ravishankar,
  K.V.S.Hari, Pages 1-4.
• Performance Evaluation and Real Time
  Implementation of Subspace, Adaptive and DFT
  Algorithms for Multi-Tone
• Detection-Guner Arslan and F.Ahyan Sakarya,
  Pages 30-34.

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Thank You
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DSP Starter Kit (DSK)
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5416 DSK Diagnostics Utility
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Code Composer Studio (CCS) Integrated
Development Environment v 2.1
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EDITOR
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Linker (Build All)
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Compiler/Assembler