Toshiba RF Receiver for HDTV

1. Final Presentation: 12/9/2004 Team: Josue Caballero, Brett DiCio, Daniel Hooper, Efosa Ojomo, George Sewell Toshiba RF Receiver for HDTV

2. Background Information • Our sponsor is Aaron Foster • Engineering Manager • Production Engineering • TOSHIBA America Consumer Products, Inc.Manufacturing Division • TOSHIBA plant is in Lebanon, TN • Produces projection screen, and DLP (digital light projection) TVs

3. Problem Statement • Coaxial cable to be attached to the television’s tuner/RF switch • Cable can fall off, damaging assembly line or TV, incurring repair costs • Cable becomes damaged with use, needing replacement • Damaged cable can cause TV rejection, affecting productivity • Cost for the simple task of connecting and disconnecting coax is high (labor)

4. Project Requirements • Design a cost efficient wireless system • Transmits factory generated signals to be received at specified signal strength (ex. 40/65/>85 μ dB) • UHF: Ultra High Frequency • VHF: Very High Frequency • ATSC: Advanced Telecommunications Standards Committee • CATV: Cable Television • QAM: Quadrature Amplitude Modulation • The operational frequency range should be between 55.25 and 805.75 MHz.

5. Operational Concept • Assembly Line • From clean room • Hood with the mirror are attached • Inspected for contaminants • Antenna is attached to the Cable TV input • We are unconcerned with any other input • Every other TV is being tested at any time • Each station has own computer and camera

6. Operational Concept (Continued)

7. Operational Concept (Continued) • Test Stations • Camera has IR transmitter to change channel to test pattern required • Each camera is connected to computer and screen is measured for picture accuracy • Antenna in back of TV, lines up with transmitter antenna

8. Operational Concept (Continued)

9. Operational Concept (Continued) • Test Signal • Test patterns are generated in house • Signal strength can be adjusted at each station • dB specification is very specific, and derived from FCC regulations • Low-power signals must be interpreted correctly • V-Chip (Violence - Chip) • Closed Captioning (CC)

10. Test Frequency Plan • 60-80% of the receiver RF testing occurs in the Very High Frequency (VHF) band • VHF (30 MHz to 300 MHz) • Channels 3, 6, 7, 9, 12 • 61.25, 83.25, 175.25, 187.25, 205.25 MHz • UHF (300 MHz to 3.0 GHz) • Channels 14, 36, 69 • 471.25 , 603.25, 801.25 MHz • Cable • Channels 15, 16, 23, 24, 25, 48, 49 • 127.25, 133.25, 217.25, 223.25, 229.25, 367.25, 373.25 MHz

11. Frequency Allocations • The frequencies to be tested can be divided into two “bands” for the purpose of test set design • VHF Band: 61.25 MHz to 373.25 MHz • 61.25, 83.25, 127.12, 133.25, 175.25, 187.25, 205.25, 205.25, 217.25, 223.25, 229.25, 367.25 MHz • UHF Band: 300 MHz to 1.0 GHz • 373.25, 471.25, 603.25, 801.25 MHz

12. Frequency Band Designations

13. Operational Environment • Assembly line design means short distance between test stations (interference) • Assembly line machinery creates EM background noise • Rough handling of components • Easily damaged • TVs manually placed on line causes inconsistencies when lining up with antenna

14. Current Solution Problems • Stripped coax cable twisted into a bent oval for transmission antenna • Stripped coax cable coiled around a rod for receiving antenna • Inefficient design • Allows significant interference with adjacent systems • Designs are barely compatible, but work

15. Left Side

16. Top View

17. Antenna Design • RF (radio frequency) Transmission • Wavelength • Antenna length • EM Fields (electromagnetic) • Shape of antenna determines direction of flow • High directionality is has a negative impact on bandwidth

18. Antenna Testing • Equipment from Toshiba • Signal generator • Spectrum analyzer • Setup • Signal generator connected to test transmit antenna • Spectrum analyzer connected to test receive antenna • Measurements taken based on received power at a range of frequencies • Antenna is evaluated based on bandwidth and reliability

19. Antenna Testing (Continued) • Microwave signal generator • Thermal damage • Excessive cell heating, burns at high energy • Protection • Stand away, monitor output, shielding • Communications Interference • Aluminum foil provides adequate shielding • Skin depth at 50MHz is 12 μm

20. Desired Design Specifications • Highly directional antennas • Less errant signals / strong gain • Support tested bandwidth • Bandwidth (55.25 – 805.75 MHz, individual/multiple) • Antenna Gain • “Antenna gain is defined as the power output, in a particular direction, compared to ...any direction by a perfect omni-directional antenna.” (Stallings, 109)

21. Design Considerations • Current design in use • Bent toroid transmitter • Coiled receiver • Possible designs • Waveguide horn design • Multiple antenna design

22. Advantages • Horn waveguide • Single design • Wide bandwidth • Good directionality • Multiple Antennas • Easier design • More reliable in factory environment • Each station customized to specific needs

23. Disadvantages • Horn waveguide • Very susceptible to design variations • Very susceptible to physical damage • Exotic design • Multiple Antennas • More labor • SWR concerns (standing wave ratio) • Multiple designs means more custom maintenance

24. References • www.microsoft.com visio free trial • Cheng, David K.; Field and Wave Electromagnetics; Prentice Hall, 2nd ed. 1989. • http://www-pw.physics.uiowa.edu/plasma-wave/istp/polar/fig3.gif • http://www.bsjm.com.cn/04/images/mdsbxz.jpg • http://www.ntia.doc.gov/osmhome/allochrt.pdf • http://www.gpsw.co.uk/ProdImg/prod1875s.jpg • http://www.ramayes.com/horn_antennas.htm • “Data and Computer Communications”, William Stallings, 2004 (C)Prentice Hall New Jersey pg. 109