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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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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 User B User A
DTMF = Dual Tone Multi Frequency COR & PTT
Inside A Real Repeater 146.16 146.76
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)
Should not have inappropriate interference with transmitter and receiver!!!
Controller!! New vs. Old • New Technology • Auto-Patch • Smart Identification • Remote Shutdown • “Kirchunking” • Optically Coupled Relays Motorola Microprocessor
System Concept • Audio Amplifier • Microprocessor • Memory • Transmitter/Receiver • Opto/Audio Isolators • DTMF Decoder • DTMF Encoder • Tone Generator • Telephone
Transmitter Activation Start Is COR HIGH? Yes Set PTT HIGH NO Is COR HIGH? Set PTT LOW Courtesy Tones Start Hang Time NO Yes
Identification/Courtesy Tones 555/556 Timer Tone Generator PIC Voice Chip “W8CUL /R”
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
Initialize Telephone Call Possible Band-Pass Filters
Callsign Programming Interrupt (PB7:PB4) Begin - End = ENTER
Micro-Controller vs. Personal Computer • Versatile • Low-power • High-Speed • Low-Cost • Wide Operating Temperature Ranges
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
Overview • Complete System package • Compatibility • Simple • Affordable • Functional • Reliable
Thanks for your patience. Group Members: Bahassan, Maher Rosendale, Matt Rossetti, Anthony Special Thanks To: Dr. Nutter Dr. Palmer Marconi