NI @ ECE.UTAustin.Edu

Contributions by Profs. Francis Bostick, Bruce Buckman, Robert Heath, Archie Holmes, Jon Valvano.Additional contributions by Vishal Monga, Zukang Shen, Ahmet Toker, and Ian Wong, also UT Austin.

http://www.ece.utexas.edu http://www.wncg.org

Prof. Brian L. EvansDept. of Electrical and Computer Engineering

The University of Texas at Austin, Austin, Texas USAbevans@ece.utexas.edu

Outline

• Introduction

• Real-Time Digital Signal Processing (DSP) Lab Course

• Wireless Communications Lab Course (Prof. Robert Heath)

• Prototyping Ad-Hoc Networks (Prof. Robert Heath)

• Conclusion

http://www.ece.utexas.edu/~bevans/courses/realtime/

http://www.ece.utexas.edu/~rheath/courses/wirelesslab/index.php

Introduction

• ECE Department at UT Austin– 62 tenured and tenure-track faculty (expanding to 75)– 1500 undergraduate and 600 graduate students

• LabVIEW license for ECE predates 1996– May be installed on any ECE machine or any ECE student machine

• Use of NI products in ECE courses predates 1996– Required junior-level electronics lab course– LabVIEW coupled with NI data acquisition system to

measure time and frequency responses of devices

10 ECE faculty positions open

Introduction

• The Wild West of course numbering at UT Austin– First digit indicates the number of credits– Middle digit of 0 means first-year undergraduate course– Middle digit of 1 means second-year undergraduate course– Middle digit of 2-7 means upper division course– Middle digit of 8-9 means graduate course– I just work here …

• EE 302 Introduction to Electrical Engineering– Required for first-year first-semester ECE students– Use NI ELVIS workstation for all analog circuits labs– Saves significant amount of lab space

Prof. Archie Holmes

EE 438 Electronics I – Lecture Component

• Junior-level required course for both majors• In-class demonstrations using NI ELVIS

– Demonstrate performance of a variety of electronic circuits– Project ELVS board using a document camera– Switch to simulated measuring instruments to analyze performance

• In-class demonstrations using NI Electronics Workbench– Often coupled with ELVIS demonstration

• Similar approach for EE 338K Electronics II– Junior-level elective for both majors

Prof. Francis Bostick

EE 438 Electronics I – Lab Component

• Objectives of junior-level required course for both majors– Make time- & frequency-domain measurements on electronic circuits– Utilize measurements with predictions from circuit simulation software

(like PSPICE or MultiSIM) to troubleshoot circuits• Automated stimulus/response measurements

– Diode rectifiers and amplifiers based on MOSFETs & BJTs– Using NI digital acquisition hardware controlled by

suite of LabVIEW Express VIs developed for course• Entire lab content delivered to students via the Web

http://www.ece.utexas.edu/~buckman

Prof. Bruce Buckman

EE 362K Intro to Auto. Control

• Required senior-level course for BSEE majors– Uses LabVIEW to design feedback control systems

• System identification of system to be controlled – Students interactively add/delete poles/zeros from a transfer function

until it agrees with time and frequency measurements of the plant• Analog controller design to tailor closed-loop system

– Students interactively add/delete poles/zeros in controller to achieve target closed-loop system performance in time and frequency

• Digital controller design for implementation– Students interactively modify controller to fix problems

as sampling frequency lowered toward realistic final value

Prof. Bruce Buckman

EE 464 Senior Design Project

• Required senior-level course for all majors– Students work individually or in teams of two

• Sample projects using LabVIEW– Shaun Dubuque and Richard Lam, “Vital Signs Monitor”– Steven Geymer and Matt Dione, “Infrared Eye Tracking

System with Distributed Control”– Stephen Pun, "Discrete Multitone Modulation Modem Testbed“– Altamash Janjua and Umar Chohan, "OFDM Transmitter Based on the

Upcoming IEEE 802.16d Standard“http://www.ece.utexas.edu/~bevans/courses/ee464/AltamashJanjua/finalreport.htm

– Abdelaziz Skiredj, "Quantifying Tradeoffs in Adaptive Modulation Methods for IEEE 802.16a Wireless Communication Systems"

Selected Graduate Courses

• EE 382C-9 Embedded Software Systems– System-level modeling and simulation (breadth)– Dataflow modeling, scheduling, and synthesis (depth)– LabVIEW is homogeneous dynamically-scheduled dataflow model

http://www.ece.utexas.edu/~bevans/courses/ee382c • EE 385J-17 Biomedical Instrumentation II

– Lab 1. Analog/Digital Noise Analysis w/ LabVIEW– Lab 2. Heart Sounds w/ LabVIEW– Lab 5. Embedded System Project (LabVIEW or 9S12C32)

http://www.ece.utexas.edu/~valvano/BME385Jinfo.html

Prof. Brian Evans

Prof. Jonathan Valvano

Real-Time DSP Course: Overview

• Objectives of undergraduate elective class– Build intuition for signal processing concepts– Explore signal quality vs. complexity tradeoffs in design– Translate DSP concepts into real-time software

• Lecture: breadth (three hours/week)• Laboratory: depth (three hours/week)

– Deliver voiceband transceiver using TI DSP processors/tools– Test/validate implementation using NI LabVIEW and rack equipment

• “Design is the science of tradeoffs” (Prof. Yale Patt, UT)

Over 600 served

since 1997

Real-Time DSP Course: Show Me The Money

• Embedded system demand: volume, volume, …– 400 Million units/year: automobiles, PCs, cell phones– 30 Million units/year: ADSL modems and printers

• How much should an embedded processor cost?

Consumer Electronics Product

Average Unit Price

Annual Revenue

Wireless phone $136 $11.5 Billion

Digital cameras $271 $ 4.2 Billion

Portable CD players $ 48 $ 0.9 Billion

MP3 players $137 $ 0.7 Billion

Compact audio systems $111 $ 0.5 Billion

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Real-Time DSP Course: Which Processor?

• How many digital signal processors are in a PC?• Digital signal processor worldwide revenue

– $6.1B ‘00, $4.5B ‘01, $4.9B ‘02, $6.1B ‘03, $8.0B ‘04– Estimated annual growth of 23% until 2008– 43% TI, 14% Freescale, 14% Agere, 9% Analog Dev (‘02)

• Fixed-point DSPs for high-volume products– More than 90% of digital signal processors sold are fixed-point– Floating–point DSPs used for initial real-time fixed-point prototype– Floating-point DSP resurgence in professional and car audio products

• Program floating-point TI TMS320C6700 DSP in CRevenue figures from Forward Concepts (http://www.fwdconcepts.com)

Real-Time DSP Course: Textbooks

• C. R. Johnson, Jr., and W. A. Sethares,Telecommunication Breakdown, PH, 2004– “Just the facts” about single-carrier transceiver design– Matlab examples– CD supplement featuring Rick Johnson on drums

• S. A. Tretter, Comm. System Design using DSPAlgorithms with Lab Experiments for theTMS320C6701 & TMS320C6711, Kluwer, 2003– Assumes DSP theory and algorithms– Assumes access to C6000 reference manuals– Errata/code: http://www.ece.umd.edu/~tretter

Bill Sethares (Wisconsin)

Steven Tretter (Maryland)

Real-Time DSP Course: Where’s Rick?

Rick Johnson (Cornell)

Real-Time DSP Course: QAM TransmitterLab 4 Rate

Control

Lab 6 QAM

Encoder

Lab 3Tx Filters

Lab 2 Passband

Signal

LabVIEW reference design/demo by Zukang Shen (UT Austin)

http://www.ece.utexas.edu/~bevans/courses/realtime/demonstration

Real-Time DSP Course: QAM TransmitterControl

panel

QAMpassband

signalEye diagram

LabVIEW demo by Zukang Shen (UT Austin)

square root raised cosine, roll-off = 0.75, SNR = passband signal, 1200 bps modeReal-Time DSP Course: QAM Transmitter

raised cosine, roll-off = 1, SNR = 30 dB passband signal, 2400 bps mode

Real-Time DSP Course: Lab 2. Sine Wave Gen

• Ways to generate sinusoids on chip– Function call– Lookup table– Difference equation

• Ways to send data off chip– Polling data transmit register– Software interrupts– Direct memory access (DMA) transfers

• Expected outcomes are to understand – Signal quality vs. implementation complexity tradeoffs– Interrupt mechanisms, DMA transfers, and codec operation

Real-Time DSP Course: Lab 2. Sine Wave Gen

• Evaluation procedure– Validate sine wave frequency on scope– Test subset of 14 sampling rates on board– Method 1 with interrupt priorities – Method 1 with different DMA initialization(s)

LabVIEW DSP Test Integration Toolkit 2.0

Code Composer Studio 2.2

C6701DSP

Old School

HP 60 MHz

Digital Storage

Oscilloscope

New School

Real-Time DSP Course: Lab 3. Digital Filters

• Implement digital linear time-invariant filters – FIR filter: convolution in C and assembly– IIR Filter: direct form and cascade of biquads, both in C

• Expected outcomes are to understand – Speedups from convolution assembly routine vs. C– Quantization effects on IIR filter stability– FIR vs. IIR: how to decide which one to use

• Filter design gotcha: polynomial inflation– Polynomial deflation (rooting) reliable in floating-point– Polynomial inflation (expansion) may degrade roots– Keep native form computed by filter design algorithm

x[k] y[k]Unit

Delay

UnitDelay

1/2

1/8

y[k-1]

y[k-2]

Real-Time DSP Course: Lab 3. Digital Filters

• IIR filter design for implementation– Butterworth/Chebyshev filters special cases of elliptic– Minimum order not always most efficient– In classical designs, poles sensitive to perturbation– Quality factor measures sensitivity of pole pair to oscillation:

Q [ ½ , ) where Q = ½ dampens and Q = oscillates• Elliptic analog lowpass IIR filter example [Evans 1999]

Q poles zeros

1.7 -5.3533±j16.9547 0.0±j20.2479

61.0 -0.1636±j19.9899 0.0±j28.0184clas

sica

l Q poles zeros

0.68 -11.4343±j10.5092 -3.4232±j28.6856

10.00 -1.0926±j21.8241 -1.2725±j35.5476 opti

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Real-Time DSP Course: Lab 3. Digital Filters

• Evaluation procedure– Sweep filters with sinusoids to construct magnitude/phase responses

• Manually using test equipment, or• Automatically by LabVIEW DSP Test Integration Toolkit

– Validate cut-off frequency, roll-off factor…– FIR: Compare execution times

• C without compiler optimizations• C with compiler optimizations• C callable assembly language routine

– IIR: Compute execution times• Labs 4-7 not described for sake of time

Test Equipment

Agilent Function Generator

HP 60 MHz Digital Storage OscilloscopeSpectrum Analyzer

Wireless Comm. Lab: Overview

• A typical digital communication system

SourceSourceCoding

ChannelCoding

ModulationAnalog

Processing

AnalogProcessing

De-modulation

PropagationMedium

ChannelDecoding

SourceDecoding

Sink

Transmitter

Receiver

Channel

DigitalDigital AnalogAnalog

Physical world

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Wireless Comm. Lab: A DSP Approach

• Decompose block diagram into functional unitsInputsInputs SystemSystem OutputsOutputs

01101100110110

timetime

timetime

h[n]h[n]

h(t)h(t)

01101100110110

timetime

timetime

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Wireless Comm. Lab: Premises

• Learning analog communication e.g. AM/FM are no longer essential (think vacuum tubes)

• A digital communication system can be abstracted as a discrete-time system

• Concepts from signals and systems can be used to understand the complete wireless system

• Experimental approach to wireless builds intuition on system design

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Wireless Comm. Lab: Course Topics

• DSP models for communication systems– Sampling, up/downconversion, baseband vs. passband– Power spectrum, bandwidth, and pulse-shaping

• Basics of digital communication– QAM modulation and demodulation– Maximum likelihood (ML) detection

• Dealing with impairments– Channel modeling, estimation and equalization– Sample timing, carrier frequency offset estimation– Orthogonal frequency division multiplexing (OFDM)

Initial offering in Spring 2005

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Wireless Comm. Lab: One Lab Station

SourceChannelCoding

Modulation RF Up

RF DownA/D

Channel

DemodDecodingSink

Transmitter

D/A

Receiver

PXI-5610PXI-5421

Dell PC with LabVIEW softwareMXI-3 SMA

PXI-5600PXI-5620

PXI Chassis

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Wireless Comm. Lab: One Lab Station

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Prototyping Ad Hoc Networks: Introduction

• Ad hoc networks are loose collections of nodes– Important for military applications– Applications to in-home networking

• Prototyping requires physical & network software

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Prototyping Ad Hoc Networks: Description• Radio

– RF transceiver uses TI IEEE 802.11a/b/g radio– ADC / DAC using NI 5620 and NI 5421

• Physical layer– In LabVIEW on embedded PC in PXI chassis

• PHY / MAC interface– Gigabit Ethernet

• Medium access control– Implemented in Linux on dedicated PC

• Networking (packet routing, etc.)– Implemented using Click Modular Router (C++)

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

MIMO-OFDM Ad Hoc Network Prototype

Profs. Robert W. Heath, Jr., Scott Nettles (UT Austin)

and Kapil Dandekar (Drexel)

Funding from NSF and NI

Equipment donations from Intel, NI, and TI

Prototyping Ad Hoc Networks: Node Diagram

RF Front-end(TI)

RF Front-end(TI)

A D D AC C

N NI I5 56 42 20 1

MIMO/OFDMRecv

PHYCntrl

NI PXI CHASSIS Dell X86 Linux Host

PXI 8187 ControllerLabVIEW

Click ModularRouter (C++)

MIMO/OFDMSend

GigabitEthernetPXI 8231 MIMO

MACAd-HocNet

App

NI 5620 64Mb buffer

NI 5421 256Mb buffer

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu

Prototyping Ad Hoc Networks: Two Nodes

Slide by Prof. Robert W. Heath, Jr., UT Austin, rheath@ece.utexas.edu