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Detailed Design Review Group 2 EE4346 Fall 2001 Date: 11-08-01

Detailed Design Review Group 2 EE4346 Fall 2001 Date: 11-08-01. Introduction. Objective Design approach Group Division Project Overview - FEC Group -------------------------------------Brion - Frequency Hopping Group ------------------Wyatt

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Detailed Design Review Group 2 EE4346 Fall 2001 Date: 11-08-01

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  1. Detailed Design ReviewGroup 2EE4346Fall 2001Date: 11-08-01

  2. Introduction • Objective • Design approach • Group Division • Project Overview - FEC Group -------------------------------------Brion - Frequency Hopping Group ------------------Wyatt - Antenna Design Group -----------------------Abdelhafeed - Testing and Packaging Group ---------------Mohammad • Summary -------------------------------------------Mohammad

  3. PC 1 PC 2 TRF6900A EVK TRF6900A EVK Objective • To transfer data from one PC to another with minimal or no • errors in the range of about 100 ft. • It would posses the error correcting capabilities by using • FEC (forward error correction) • Frequency hopping would be implemented to make the • data transfer more secure.

  4. Design Approach • The design would be implemented using TRF6900A EVK • due to it’s easy availability. • Onboard micro-controller (MSP430F121) would be • bypassed with a better micro-controller (MSP430F149) due • to limited memory. • The new micro-controller would be programmed accordingly • to implement FEC and frequency hopping.

  5. Group Division Wireless Team Team Leader: Mohammad Butt FEC Group Frequency Hopping Group Antenna Design Group Testing and Packaging Group Brion Mohammad Wyatt Irving Michael Brion Mohammad Wyatt Irving Michael Steve Anthony Abdelhafeed Asim Brion Mohammad Wyatt

  6. Frequency (max) (MHz) 950 Frequency (min) (MHz) 850 Standards Supported FSK, narrow-band FM Power Output (dBm) 5 Operating Voltage (V) 2.2 - 3.6 Standby Current (uA) 0.5 Package 48-pin PQFP EVK 6900A

  7. EVK 6900A • Transmitter • Serial interface • Direct digital synthesizer • Voltage controlled oscillator • Phase locked loop • Power amplifier • Receiver • Low noise amplifier • Mixer • IF amplifier • Received signal strength indicator (RSSI) • FSK demodulator • Data slicer

  8. Forward Error Correction • 7-5 Convolution Encoding • Viterbi Decoding Group Leader: Brion Group members: Mohammad, Wyatt, Michael, Irving

  9. Group Responsibilities Brion - Research on FEC, TRF6900A, coding in assembly for FEC, documentation, testing and packaging final design Mohammad – Research on frequency hopping, TRF6900A, interfacing EVK 6900A with computer, documentation, assist in FEC scheme, testing Wyatt - Implementation of frequency hopping, research on TRF 6900A, coding in assembly for FEC. Irving - Research on TRF6900A, frequency hopping, functioning of DDS in TRF6900A, documentation Michael- Research on FEC, MSP430F149, documentation.

  10. Forward Error Correction Methods • Block Coding Using Matrices With Maximum Likelihood Decoding • Convolution Encoding With Viterbi Decoding • Reed Solomon Encoding & Decoding

  11. 7-5 Convolution Encoder

  12. 7-5 Convolution Encoder

  13. FEC Timeline

  14. FEC Obstacles • Selecting an FEC method. • Understanding Viterbi Decoding Algorithm. • Obtaining replacement microprocessors and programming tools.

  15. Projected Functionality • I expect, provided we get the microprocessor and programming tool within the next week, we will be able to implement FEC. • Implementing frequency hopping is probably out of the question, unless we forego the final write up.

  16. Frequency Hopping Group Leader: Irving Smith Group members: Mohammad, Wyatt, Michael, Brion

  17. Advantages of Frequency Hopping • Security • Anti-Jamming • Multiple access per frequency • More power allowed by FCC • Looks pretty on a spectrum analyzer

  18. Frequency Hopping Scheme 927.6 MHz 256 divisions @ 100kHz each S = random seed C= T – T0 Fnext = (S*Fcurrent + C) mod 256 *100kHz + 902MHz 902 MHz

  19. Antenna Subgroup • Abedalhafeed Alazzam: Antenna research, fabrication, testing • Steven Bean: Antenna research, fabrication, testing, documentation • Anthony Clay: Antenna research, fabrication, testing, documentation • Asim Khan: Research antenna switching

  20. Antenna Block Diagram • Half Duplex Transmission • Transmission Medium is Air • Switch Defaults to Receiving Mode

  21. Antenna Design Concept of the Microstrip Patch Antenna

  22. ISM Band • ISM (Industrial Scientific Medical) Band • 902 – 928 MHz • Center Frequency of 915 MHz

  23. Physical Characteristics • Dielectric substrate is sandwiched between two metallic planes • One plane acts as the ground plane • Smaller patch resonates the signal

  24. Wave Propagation • Coaxial cable feeds resonating patch • Longer sides of patch resonate signal • Fields are perpendicular to patch (z-direction)

  25. Antenna Fabrication Chemical Etching Procedure

  26. Preparing the Circuit Board • Copper is protected by the “etch-resist” ink • Template is cut to the dimensions of the resonating patch and colored in

  27. Preparing the Circuit Board • Reverse side serves as ground plane • Must be completely colored in to preserve copper layer

  28. Preparation of Solution • Ferric chloride is used to dissolve the exposed copper • Must be diluted with water • Warm solution to 75°F for best results

  29. Exposing the Board to the Solution • Board is submerged in solution • Board is slowly agitated during the process • All uncoated copper should be removed • Exposure time should be approximately 20 minutes

  30. Ongoing and Future Research • Impedance Matching • Connection of coaxial cable to patch • Feed location is used to match impedance • ViPEC Software • High frequency network analysis software • Aids in the calculation of transmission line parameters

  31. Ongoing and Future Research • Testing • Network Analyzer • Measure return loss, VSWR and impedance characteristics • Anechoic Chamber • Radiation patterns • Gain measurements • Antenna Switch • Selects between transmitting and receiving modes

  32. Antenna Group Timeline

  33. Testing and Packaging Group Group Leader: Wyatt Group members: Mohammad, Wyatt, Brion

  34. Objective • To test different components of the system at different • stages of the project (task for all members) • Develop a plan on how the final testing would be • carried out • If time permits then we would also package the final • product

  35. Test Plan • Initial test involves setting up the EVK 6900A • and testing it with the TI software • Flash the new micro-controller and test it with • existing code to make sure it is connected • properly to the flash tool • Test the board with new code for FEC to achieve • the desired result.

  36. Test Plan • Test the antennas with the EVK 6900A and • check for any irregularities • Test the received data for any spurious responses • using spectrum analyzer • Test the entire system within a range of 100 ft • Test for frequency hopping phenomenon if • implemented

  37. Timeline for Testing & Packaging Group

  38. Summary • If everything goes as planned we would be able to transfer • data from one PC to another using FEC within a 100 ft range. • Efforts are being made to reduce data error to a minimal • The team would try it’s best to implement frequency hopping • to make the data transfer more secure

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