Wireless Sensor Systems Design Course
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Transcript of Wireless Sensor Systems Design Course
Wireless Sensor Systems Design Course
A Joint Course of the University of South Florida
and Tennessee Technological University
Spring 2002
Lecture 1 - Analog and Digital Modulation Methods
(as applicable to the project)
Tennessee TechUNIVERSITY
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Weekly Lecture Topics Course Introduction Analog and Digital Modulation Methods (1/11) Fundamentals of Antennas and Propagation (1/18) Signal Detection and 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 TBD (3/1) TBD (3/8) Critical Design Review (student presentations*) (3/22) Microelectromechanical Systems (MEMS) Sensors (4/5) Modern Wireless Communication Systems (4/12) @ USF Review / Course Wrap-up (4/19)
* On-site internal reviews/preparation will precede inter-university presentations.
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Outline
What are we trying to do in this project? Systems Approach
How do we get information sent over a wireless link?
What are some transmission options for the AW3 project?
What are some receiver options?
Wrap up / Assignment 1
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
AW3 - System Overview
CentralReceiver
Sensor: Temperature, Light Intensity, Humidity, Position
Sensor 1
Sensor 2
Sensor 3 Sensor 4
Sensor n
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
The BIG Picture
Sensor: Temperature, Light Intensity, Humidity & Location
Data for 01APR01
Time Sensor °C Intensity Humidity1532 26 24 70% 50%1533 14 25 65% 55%1544 29 30 0% 60%… … … … …… … … … …… … … … …
Historical Data:By timeBy sensorBy location
http://iweb.tntech.edu/jfrolik/sensors.html
Sensor 14: °C
Date/time
Sensor n
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
GPS
How are we going to get there?
Baseband
DC Power
TempIntensityHumidity
RF TX Antenna
Baseband
DC Power
SignalProcessing /
WEBRF RXAntenna
ENVIRONMENT
USER
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Modulation!
Puts baseband information onto a high frequency carrier
Why? Effective wireless transmission only at higher
frequencies (dimensions proportional to λ). Signal isolation (think FM radio) More bandwidth available
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
General carrier
AM
FM
PM
The BIG 3
)()( tmkt fci
)cos()( ccc tAtc
)()( tmkt pi
)cos()]([)( ccAM ttmAt
))(cos()( dttmktAt fccFM
Info: m(t)
))(cos()( tmktAt pccPM
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Digital Methods (time domain representation)
amplitude
phase
frequency
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Nest Watch - 915 MHz Transmitter (AM example)
Battery
Oscillator: cos(ct)
Filter Amplifier
Loop Antenna
Information Signal: s(t) AM(t)=s(t) cos(ct)
Options for s(t) : AM: s(t)=A+m(t) envelope detector DSB-SC: s(t)=m(t) synchronous detector
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
AM (large carrier)
What is sent: What do we want? Envelope detection (i.e., simple receiver) can be used:
)cos()]([)( ttmAt cAM )(tm
1A
mp
mod index:
1. Rectify2. LP Filter3. DC Block
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Last Year’s Design
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Last Year’s Design
baseband
transmitterreceiver
antenna
proximitysensor
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Phase and Frequency Modulation
AM is a linear function Bandwidth of modulated signal:
FM and PM are non-linear methods Bandwidth of modulated signal Power series:
mAM BB 2
)1(2 mEM BB
)sin)(!3
cos)(!2
sin)([cos)(
33
22
ttmk
ttmk
ttmktAt
cp
cp
cpcPM
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Ideas for this year
Analog FM system
Digital FSK system
Digital PSK system
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
What are the knowns in our design?
RF section Transmitter Components
550 MHz VCO (TTU/USF interface frequency) Upconverted to 2.4 GHz (USF)
Receiver Components Direct to baseband Or to 550 MHz IF and PLL
Baseband Bandwidth: Sound card for processing (?) Signal content Bm< 20 kHz RF receiver must be match to baseband method
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Key Component: VCO
Voltage Controlled Oscillator Center Frequency: 550 MHz Tuning range: 42 MHz (centered?) Tuning rate: 14 MHz/volt Tuning voltages: 0-3 volts (?)
volts
time
VCO freq
time
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
FM/FSK
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
FM Transmitter
)(tmconditioning VCO X filter
synthesizer
< 20 kHz+/- 5 Volts
centered:550 MHz 2.4 GHz
)(/ tFSKFM
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
PSK
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
PM Transmitter
)(tmconditioning
VCO Xswitch
synthesizer
Binary: 0 & 1< 20 kHz
+/- 5 Volts
fixed:550 MHz
2.4 GHz
filter
filter0°
180°
)(tPSK
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Analog FM Receiver/PLL
)(tFMfilter
VCO
X filter
synthesizer
< 20 kHz
550 MHz2.4 GHz
X filter )(tm
PLL: phase locked loop
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
FSK Receiver
)(tFSKfilter
VCO
X filter
synthesizer
535 MHz (?)or
565 MHz (?)2.4 GHz
X
“1” filter detector
“0” filter detector
530 MHz (?)
35 MHz
5 MHz
compare
0 or 1
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
PSK Receiver
)(tPSKfilter
VCO
X filter
synthesizer
2.4 GHz
X 0 or 1PHASEDETECTOR
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Baseband options
“Analog” Decimal data (i.e., 0-9) is encoded with baseband tones
Think touch-tone phone (see www.dtmf.info for ideas) Baseband signal drives VCO
FM modulation PLL receiver
Digital PCM encode information (i.e., analog to 0’s and 1’s) Use binary signal to FSK or PSK modulate IF Unique RF receiver for each method
However PLL could be used for FSK Baseband signal processing may be very similar
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Wrap Up
Need quick answer to the following:
USF: What are the specifics of the VCO?
TTU: What are the two baseband methods to be pursued? This will influence receiver design.
TTU: Will the signal processing approach be hardware, software or a hybrid?
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Assignment 1
Visit the course WebBoard site (USF students: send Frolik name and email address) DONE!
Post a short bio and hours of availability Post your bios by 1/18 TTU “reply” to TTU student board: TTU Bios USF “reply” to USF student board: USF Bios
Learn how to use NetMeeting
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
WebBoard
Very user friendly means of putting information on a web-site for the project.
Items that will be posted during this course Reports for peer review (.doc) Tutorial presentations (.pdf) Interim student presentations (.ppt) Any information that needs to be shared within and between
teams Link: http://webboard.tntech.edu:8080/~ee-projects
LET FROLIK KNOW ASAP IF YOU CAN’T LOG ON
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Additional Notes on Assignment 1 (USF)
Download information on EE Senior Design Project requirements (http://ee.eng.usf.edu/undergraduate/seniordesign/)
Submit ½ page project proposal in electronic format Generate tentative project schedule for the semester
You must participate in the poster competition at the end of the semester. Your poster must contain 1 slide about the broader aspects of the course project (suggest you do some research on sensors)
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Coming Soon!
Tutorial from USF:
Fundamentals of Antennas and Propagation (1/18)
Tutorial from TTU:
Signal Detection and Processing Techniques (1/25)
One page project description due 1/25. “Reply” TTU/USF reports: Project Descriptions
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Two Month Course Schedule
January Week 1 (7-11) Week 2 (14-18)
Choose project Literature search
Week 3 (21-25) Literature search Submit project description (1 page;
references from literature search) and tentative schedule (design; fabrication; test; report)
February Week 4 (28-1)
First progress report Week 5 (4-8)
Review peer reports Week 6 (11-15)
Parts list due Preliminary Design Review
Week 7 (18-22) Weller at TTU
1. All inputs are due on Friday of the specified week - no exceptions2. Reviews of peer reports must be completed before the lecture on Friday
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Format for Progress Reports
Brief project description and purpose (1-3 sentences) Objectives for the current reporting period (2-3 sentences) Progress for the current reporting period (2-3 paragraphs; use figures and
graphs where needed - they can be reused in your final project report) Plans for the upcoming project period (2-3 sentences) Revised Project Schedule
Keep in mind that the peer(s) who review your report may not be intimately familiar with your project, so you need to clearly explain the objectives and outcomes.
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Peer Review Process
Grading criteria: Clarity of report Level of progress made during reporting period Clear goals for upcoming project period
You are required to turn in reviews for two peer reports that will be assigned to you. You should include brief comments/suggestions and an overall grade of G (good), P (passing), and U (unsatisfactory). Hand-in the reports with your name attached, but NOT written on the report (the reviews are anonymous). Two “U” grades from peers will result in a loss of credit for the student, unless overridden by the instructor(s).
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Think about Subsystem Requirements
Functional What must the subsystem do? To what performance level must this be
accomplished? Interfaces
Electrical (DC) Signal (frequency, voltages, etc.) Dimensions Packaging
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Final Comments
The success of the project (i.e., course) depends on the efforts of all students
Subsystems must work closely to ensure interface requirements are properly defined and met
Need to establish contacts in other groups, ASAP!
Schedule is aggressive: Work early and often!
USF EEL 4935/TTU ECE 4720SPECIAL TOPICS: WIRELESS SENSOR SYSTEMS
Tennessee TechUNIVERSITY
Anything else?