Tennessee Tech
UNIVERSITY
Wireless Sensor System Design
A Joint Course of the
University of South Florida
and
Tennessee Technological University
Spring 2002
Lecture 5 - Systems Engineering / Effective Presentations
Weekly Lecture Topics





Course Introduction
Analog and Digital Modulation Methods (1/11)
Fundamentals of Antennas and Propagation (1/18)
Signal Processing Techniques (1/25)
Microwave Systems: Communications Hardware, Noise, Linearity (2/1)
 System Test, Evaluation and Documentation / Effective Presentation
Styles (2/8)








Preliminary Design Review (student presentations*) (2/15)
Microwave Sensor Technology (2/22) @ TTU
Modern Wireless Communication Systems (3/1)
TBD (3/8)
Critical Design Review (student presentations*) (3/22)
Microelectromechanical Systems (MEMS) Sensors (4/5)
Wireless Sensor System Research (Paul Flikkema from NAU) from USF (4/12)
Review / Course Wrap-up (4/19)
* On-site internal reviews/preparation will precede inter-university presentations.
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Today’s Tutorial
 Systems Engineering
 What is it? Why is it needed?
 Answer through example:
Communication Satellites
 How does this relate to our project?




Design
Integration
Test
Documentation
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
What is a Communication Satellite?
 Repeater in the sky
D/C
AMP
14 GHz
12 GHz
 Two main subsystems:
 Support functions (BUS)
 Specific functions
(PAYLOAD)
Note: Full system consists of both space and earth segments
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Block Diagram for a Satellite System
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Block Diagram of Payload Subsystem
PAYLOAD
Passive Components
Active Components
Antennas
filters
amplifiers
low-power
horns/
feed networks
couplers/
isolators
down/up
converters
reflectors
switches
amplifiers
high-power
structures
waveguide
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Types of Engineers Needed
 Numerous disciplines with specialized talents
 EE
 Controls, Electronics, Microwave Devices
 Antenna, Communications
 ME
 Structures, Dynamics, Thermal
 ChemE
 Propulsion, Fuel Cells
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Who understands the BIG PICTURE?
???
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Who understands the BIG PICTURE?
 Systems Engineer
 Broad base / interdisciplinary knowledge
 Not about knowing all the answers
 About knowing and asking the right questions
 Liaison between subsystems and
management/customers
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Typical Systems Engineering Problem




Efficiency of 100 W TWTAs are 55 % vs. 60%
DC load/unit = 181 W vs. 167 W
14.3 W/unit delta
PRF _ out

24 units: 344 W extra
PRF _ in  PDC _ in
 Overall bad situation:
 Solution 1: Live with it
 Solution 2: Back-off output power
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Solution 1: Live with it
 Excess power:
 needed from solar
panels/batteries
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Solution 1: Live with it
 Excess power:
 needed from solar
panels/batteries
 dissipated as heat
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Solution 1: Live with it
 Excess power:
 needed from solar
panels/batteries
 dissipated as heat
 Excess heat:
 larger heat sinks
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Solution 1: Live with it
 Excess power:
 needed from solar
panels/batteries
 dissipated as heat
 Excess heat:
 larger heat sinks
 larger spacing between
units
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
Other involved groups: reliability, layout,
mass properties, propulsion, launch, etc.
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Solution 2: Reduce RF output
 Idea: Don’t impact BUS
 Back off output from
100 W to 91.8 W
 -0.4 dB change
 Could eat all the design
margin!
 Customer is paying for
EIRP!
Satellite
BUS
PAYLOAD
structures
passive
propulsion
active
power
antenna
thermal
controls
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Systems Design Strategy
 Flow top level specifications to subsystems
 Flow subsystem specs to units
 Example: EIRP spec of 55 dBW
 Repeater
 100 W Amplifier:
 Output Losses:
 Antenna
 Gain:
 Feed Losses/efficiency:
 Margin
20.00 dbW
-1.50 dB
Beating spec
at a cost?
38.00 dBi
-1.00 dB
> 0.50 dB
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Spec Flow Example Continued
 Output Losses
 Isolator
 Waveguide*
 Switch
 Waveguide*
 Output Filter
 Isolator
 Waveguide*
 Coupler
 Total
Margin
-1.50 dB
-0.15
-0.15
-0.15
-0.20
-0.40
-0.15
-0.10
-0.15
-1.45 dB
.05 dB
*Layout dependent
Known measured value: -0.12 dB
Note: subsystem
and unit margins
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Design Evaluation
 Proposal
 Preliminary Design Review (PDR)
 internal and external review of system design,
schedule and test plan
 results in action items
 Critical Design Review (CDR)
 same, but more of it!
 Test spec and test results
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Testing: Early and Often
1. Unit Level
 Ambient Test
 Burn in, Thermal and
Vibration
 Ambient Test
2. Subsystem Integration
& Test
 Test as sections
 Test as subsystem
3. System Test
 Ambient Test
 Environmental: Thermal
Vac & Vibe
 Ambient Test
4. In Orbit
 Payload Test
 Bus Test
Testing costs $$$ but ensures
reliability
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
What goes in a Specification?
Interface and Performance attributes
 Physical
 Mass
 Dimensions, Layout
 Power
 DC in
 Efficiency
 Thermal
 RF
 I/O levels
 Efficiency
 Other I/O
 Telemetry
 Command
 Control
 RF and DC dissipation
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Other Documentation
 Specifications:




Unit
Subsystem
System
Test
 Design review packages
 System Summary
 Test Data
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Systems Engineering on USF/TTU Project
 Subsystem Design
 System Integration
 Design Review
 Design for Test
 Documentation
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
TTU and USF Wireless Sensor System
http://www.ece.tntech.edu/472s02/dsp/
Data for 12APR02
Time
1532
1533
1544
…
…
…
Sensor n
Sensor: Temperature,
Light Intensity, Humidity & Location
Sensor
26
14
29
…
…
…
°C
24
25
30
…
…
…
Historical Data:
By time
By sensor
By location
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Intensity
70%
65%
0%
…
…
…
Humidity
50%
55%
60%
…
…
…
Sensor 14: °C
Date/time
Tennessee Tech
UNIVERSITY
How can we ensure it will all work together?
 Design Strategy:
 Break the system into subsystems
Flow of Spec
 Break subsystems into components
 Peer review of design
PDR/CDR
 Design for test
 Integration Strategy:
 Test and document individual components
 Test and document subsystem performance
 Test and document system level performance
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Example: Design for Test - RF Transmitter
BPF
AMP
X
VCO
 How can component and subsystem performance be
determined in the same design?
 Design board to accommodate both!
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Board Layout (AM transmitter)
MIX_out
AMP_in
Baseband
TX_out
X
AMP
VCO_cntrl
BPF
VCO
Carrier
BNC connector
Note: other I/O’s are
needed (e.g., power)
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
VCO Testing
MIX_out
AMP_in
Baseband
TX_out
X
BPF
AMP
VCO_cntrl
VCO
Carrier
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Mixer Testing
MIX_out
AMP_in
Baseband
TX_out
X
BPF
AMP
VCO_cntrl
VCO
Carrier
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Modulator Testing
MIX_out
AMP_in
Baseband
TX_out
X
BPF
AMP
VCO_cntrl
VCO
Carrier
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Subsystem Testing
MIX_out
AMP_in
Baseband
TX_out
X
BPF
AMP
VCO_cntrl
VCO
Carrier
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Delivered Subsystem
Baseband
X
BPF
X
VCO
X
X
AMP
VCO_cntrl
TX_out
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
What goes in our specs?
 Interface (I/O) attributes
 DC
 Voltages/Currents
 Connector type
 Baseband




Voltages
Bandwidth
Expected signals
Connector type
 RF
 Center frequency
 Bandwidth/Power
 Connector type
 Other
 Physical dimensions
 Anything that might
effect the BIG picture
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Wrap Up
 Component level performance can effect all other
subsystems
 Systems engineers understand complex relationships
and know what questions to ask
 Specs are used to coordinate the efforts of different
engineering groups
 Design reviews check and double check methodology
 Test and document early and often!
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Bottom Line
 Appreciation of the systems engineering approach to
developing complex designs.
 Reference
G. Gordon and W. Morgan, Principles of Communications
Satellites, Wiley, New York, 1993
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Technical Presentations
 Scenario:
 20 minute conference presentation
 1 of 6 in your session
 150 sessions in a week
 You want to make your presentation (out of ~900)
memorable!
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Technical Presentations
 What is meant by “effective”?
 You get your message across.
 What is the problem?
 Why is it important?
 What did you do?
Motivation to listen
 Don’t bore your audience.
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Three Basic Rules
 1. Know your audience
 Be sure everyone understands your motivation
 Be sure most people get the big picture of what you
are doing
 Be sure a few people get the details
 2. Know your presentation: Practice
 3. Leave them wanting more
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
A True Story
Consider the unknown non-magnetic media to be a stack of homogeneous isotropic lossy
dielectric layers. Assume that probing and measuring reflection response is performed at the top of
the media. This methodology is not uncommon; e.g., radio echo sounding of glaciers is performed
in this manner. Using the homogeneous wave equation as a starting point, [2] showed the
development of a discrete-time two-component wave formulation for EM propagation through a
homogeneous lossy dielectric layer (1). Equation (1) describes the relationship between downward
th
D ,U
and upward traveling waves { n 1 n 1 } at the top of the n  1 layer to the downward and
th
D ,U
upward traveling waves { n n } of then
layer just above it.
 Dn 1 
1
U  
1  rn , n 1sn , n 1
 n 1 
 1
 r
 n , n 1
 s n , n 1   z  t n
1   0
0   Dn 
 
z  t n  U n 
(1)
Loss in the layer is modeled by the asymmetry of transfer coefficients rn ,n 1  Rn ,n 1 exp( 2 An 1 )
i
A  in0  i  i cos  i
and s n ,n 1  Rn ,n 1 exp( 2 An 1 ) . The cumulative loss is given by n 1
; where
i
i
i th
is the attenuation coefficient,
is the layer thickness and
is the angle
of
propagation
in
the
t n   n  n cos  n
n th
layer. The time for wave to propagate through the
layer is given by
.
For our purpose, the significance of (1) is that it is identical to that of the asymmetric lattice
filter from DSP theory. This formulation allows for the use of fast layer stripping algorithms (i.e.,
Levinson or Schur) to solve the inverse problem and to reconstruct the transfer (or PARCOR in
DSP) coefficients as a function of time (or space). Given a set of coefficients, the forward
scattering problem can be solved by running the algorithms backwards and synthesizing a response.
Both problems are solved exactly, including accounting for multiple reflections.
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Slides
 Be comfortable with the format (technology)
 Don’t have too many slides
 Don’t read your slides!
 Don’t put too much on your slides
 A clear and well-described picture IS worth a thousand words
 Use colors and shapes
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Traffic Monitoring Sensor - Case Study
Radar Subsystem
Antenna
2.45 GHz Hardware
20 MHz Hardware
Modulator
900 MHz Signal Relay
Antenna
Transmitter
Receiver
Signal Analysis
DAQ
Processing
Web Posting
Antenna
Coupler
2.45 GHz
LNA
20 MHz
Phase
Detector
Demodulator
Microw ave tow er
Microw ave tow er
Signal Conditioning
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Traffic Monitoring Sensor - Case Study
Radar Subsystem
Antenna
2.45 GHz Hardware
20 MHz Hardware
Modulator
900 MHz Signal Relay
Antenna
Transmitter
Receiver
Signal Analysis
DAQ
Processing
Web Posting
Antenna
Coupler
2.45 GHz
LNA
20 MHz
Phase
Detector
Demodulator
Microw ave tow er
Microw ave tow er
Signal Conditioning
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Things Microsoft never told you.
 Don’t let gimmicks bog down your presentation
 content over flash
 Make sure the colors are appropriate to the
presentation method
 Be sure versions are compatible
 Pre-load and check your files
 Have a back up!
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Another way of looking at things
 Personal style – eye contact with audience, speaking with
authority, show your own high interest, good posture, etc.
 Voice – single tones are only good for RF measurements!
 Movement – force the audience to keep their eyes alert, and watch
you not just the slides
 Time and space – if you don’t spend time on the material why
should your audience?
 Adjust to audience – are they following you?
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Preliminary Design Review - Next Friday (15Feb)
 Internal reviews by teams
 TTU on Wednesday (13Feb)
 USF on TBD.
 TTU will have 30 minutes and USF 15 minutes on Friday.
 Teams will need to work together to produce a single presentation
for each school.
 No formal report is to be written, but all the relevant information
should be in the presentation slides (provide hard copy).
 Design details, specifications, I/O, test and integration schedule
 Each school should also address the open issues that need to be
resolved so that integration with the other sub-systems can take
place.
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Two Month Course Schedule
February
 Week 4 (28-1)
 First progress report
 Week 5 (4-8)
 Review peer reports
 Week 6 (11-15)
 Preliminary Design Review
 Week 7 (18-22)
 Weller at TTU
March
 Week 8 (25-1)
 Second progress report
 Week 9 (4-8)
 Review peer reports
 Spring Break (11-15)
 Week 10 (18-22)
 Critical Design Review
 Week 11 (25-29)
 No TTU class (F)
1. All inputs are due on Friday of the specified week - no exceptions
2. Reviews of peer reports must be completed before the lecture on Friday
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY
Anything else?
USF EEL 4935/TTU ECE 4720
SPECIAL TOPIC: WIRELESS SENSOR SYSTEMS
Tennessee Tech
UNIVERSITY