xi
SECTION 4 TECHNICAL DESCRIPTIONSECTION 4 TECHNICAL DESCRIPTION
SECTION 4 TECHNICAL DESCRIPTIONSECTION 4 TECHNICAL DESCRIPTION
SECTION 4 TECHNICAL DESCRIPTION
4.1 Base Station Transceiver ......................................................... 4-1
4.1.1 Power Supply Section ................................................. 4-1
4.1.2 Receiver Section ......................................................... 4-1
4.1.2.1 Antenna Switching ............................................. 4-1
4.1.2.2 Pre-Amp, Splitter (binary distribution) ................ 4-1
4.1.2.3 All Channels Receiver ......................................... 4-1
4.1.2.4 Channel 70 Receiver ............................................ 4-2
1) High Frequency Amplifier ............................... 4-2
2) 1st IF ............................................................... 4-3
3) 2nd IF .............................................................. 4-3
4) De-emphasis .................................................... 4-3
5) Squelch ........................................................... 4-3
4.1.2.5 WX Alert (Weather Channel) .............................. 4-4
4.1.2.6 ATIS Decode (All Channel Receiver) .................. 4-4
4.1.2.7 DSC Decoding (Channel 70 Receiver) ................. 4-4
4.1.3 Transmitter Section ..................................................... 4-4
4.1.3.1 IDC Circuit ........................................................... 4-4
4.1.3.2 Buffer Driver Amplifier ........................................ 4-4
4.1.3.3 APC Circuit ......................................................... 4-4
4.1.3.4 ATIS, DSC, Encoding .......................................... 4-5
4.1.4 PLL Circuit .................................................................. 4-5
4.1.5 AF Control Section ..................................................... 4-5
4.1.5.1 AF Selection........................................................ 4-5
4.1.5.2 Line Selection ...................................................... 4-5
4.1.5.3 Speaker Selection ................................................ 4-5
4.1.5.4 Telephone, I/O, Cross-point switch .................... 4-6
4.1.6 Handset I/O ................................................................. 4-7
4.1.6.1 Audio I/O ............................................................ 4-6
4.1.6.2 Digital I/O ............................................................ 4-6
4.1.7 NMEA I/O ................................................................... 4-6
4.1.8 SeaTalk I/O .................................................................. 4-6
4.1.10 Write Data Operation .................................................. 4-6
4.2 Handset Circuit ........................................................................ 4-7
4.2.1 Outline ........................................................................ 4-7
4.2.2 Circuit constitution ..................................................... 4-7
4.2.3 Power Supply System ................................................. 4-7
4.2.4 CPU ............................................................................. 4-7
4.2.5 LCD Driver .................................................................. 4-7
4.2.6 LED Driver Circuit ....................................................... 4-7
4.2.7 Electronically Controlled Volume ................................. 4-8