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Group #13

Repeater Controller. Group #13. Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony. West Virginia University - LCSEE Department. Introduction. What is a repeater? What is DTMF?. Transmitted 146.76 MHz. User B. User A. Retransmitted = 146.76. Transmitted 146.16 MHz.

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Group #13

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  1. Repeater Controller Group #13 Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony West Virginia University - LCSEE Department.

  2. Introduction What is a repeater? What is DTMF?

  3. Transmitted 146.76 MHz User B User A

  4. Retransmitted = 146.76 Transmitted 146.16 MHz User B User A

  5. DTMF = Dual Tone Multi Frequency COR & PTT

  6. Inside The Simplest Repeater

  7. Inside A Real Repeater 146.16 146.76

  8. Controller Requirements • User changeable defined call sign - ID’s every ten minutes • Telephone Interface • Inhibits telephone communication after 3 minutes (exception emergency calls) • Remote accessing of controller • Watchdog Timer • Courtesy Tones (Half-Duplex) • RF shielding • Hang Time • Rapid Transmissions (Kirchunking)

  9. Should not have inappropriate interference with transmitter and receiver!!!

  10. Controller!! New vs. Old • New Technology • Auto-Patch • Smart Identification • Remote Shutdown • “Kirchunking” • Optically Coupled Relays Motorola Microprocessor

  11. System Concept • Audio Amplifier • Microprocessor • Memory • Transmitter/Receiver • Opto/Audio Isolators • DTMF Decoder • DTMF Encoder • Tone Generator • Telephone

  12. Projected Architecture

  13. Transmitter Activation Start Is COR HIGH? Yes Set PTT HIGH NO Is COR HIGH? Set PTT LOW Courtesy Tones Start Hang Time NO Yes

  14. Identification/Courtesy Tones 555/556 Timer Tone Generator PIC Voice Chip “W8CUL /R”

  15. Remote Access • DTMF Tones Valid Password 1 = Alternates Transmitter State “Off” - “On” 0 = Permanent Off • Telephone Valid Ring Count 5 = Alternate Transmitter State 4-Sec 2-Sec 75 VRMS @ 20HZ

  16. Initialize Telephone Call Possible Band-Pass Filters

  17. Callsign Programming Interrupt (PB7:PB4) Begin - End = ENTER

  18. Micro-Controller vs. Personal Computer • Versatile • Low-power • High-Speed • Low-Cost • Wide Operating Temperature Ranges

  19. PIC16F877 System Features • 40-Pin CMOS Flash Microcontroller • Operating Speed: DC-20MHz • 10-bit Multi Channel Analog-to-Digital Converter • Interrupt Capabilities = 14 Sources • Temperature range: -40C to 85C • Three Timers (Watch Dog) • 256 * 8 Bytes of EEPROM • 8K * 14 Words of Flash • Extensive Features

  20. Overview • Complete System package • Compatibility • Simple • Affordable • Functional • Reliable

  21. Thanks for your patience. Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony Special Thanks To: Dr. Nutter Dr. Palmer Marconi

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