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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 Tech UNIVERSITY. Weekly Lecture Topics.

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Wireless Sensor Systems Design Course

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  1. 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 Tech UNIVERSITY

  2. 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.

  3. 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

  4. AW3 - System Overview Sensor n Central Receiver Sensor 2 Sensor 1 Sensor 4 Sensor 3 Sensor: Temperature, Light Intensity, Humidity, Position

  5. The BIG Picture Sensor n http://iweb.tntech.edu/jfrolik/sensors.html Data for 01APR01 Time Sensor °C Intensity Humidity 1532 26 24 70% 50% 1533 14 25 65% 55% 1544 29 30 0% 60% … … … … … … … … … … … … … … … Historical Data: By time By sensor Bylocation Sensor 14: °C Sensor: Temperature, Light Intensity, Humidity & Location Date/time

  6. How are we going to get there? ENVIRONMENT Signal Processing / WEB Baseband Antenna RF RX DC Power GPS Antenna Baseband RF TX Temp Intensity Humidity USER DC Power

  7. 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

  8. The BIG 3 Info: m(t) • General carrier • AM • FM • PM

  9. Digital Methods (time domain representation) amplitude phase frequency

  10. Nest Watch - 915 MHz Transmitter (AM example) Oscillator: cos(ct) Loop Antenna Filter Battery Amplifier 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

  11. AM (large carrier) • What is sent: • What do we want? • Envelope detection (i.e., simple receiver) can be used: 1. Rectify 2. LP Filter 3. DC Block mod index:

  12. Last Year’s Design

  13. Last Year’s Design antenna proximity sensor receiver transmitter baseband

  14. 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:

  15. Ideas for this year • Analog FM system • Digital FSK system • Digital PSK system

  16. 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

  17. 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 (?) freq volts VCO time time

  18. FM/FSK

  19. FM Transmitter centered: 550 MHz 2.4 GHz conditioning X filter VCO synthesizer < 20 kHz +/- 5 Volts

  20. PSK

  21. PM Transmitter conditioning 0° fixed: 550 MHz filter switch 2.4 GHz filter X VCO Binary: 0 & 1 < 20 kHz +/- 5 Volts 180° synthesizer

  22. Analog FM Receiver/PLL 2.4 GHz 550 MHz filter X filter X filter < 20 kHz VCO synthesizer PLL: phase locked loop

  23. FSK Receiver 535 MHz (?) or 565 MHz (?) 35 MHz 2.4 GHz “1” filter detector filter X filter X compare “0” filter detector 5 MHz VCO synthesizer 530 MHz (?) 0 or 1

  24. PSK Receiver 2.4 GHz PHASE DETECTOR filter X filter X 0 or 1 VCO synthesizer

  25. 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

  26. 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?

  27. 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

  28. 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

  29. 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)

  30. 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

  31. Two Month Course Schedule 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 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) 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

  32. 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.

  33. Peer Review Process 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). Grading criteria: • Clarity of report • Level of progress made during reporting period • Clear goals for upcoming project period

  34. 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

  35. 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!

  36. Anything else?

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