INTEGRATE ANALOG AND DIGITAL-BASED DIGITAL SELECTIVE CALLING/VERY HIGH FREQUENCY UNMANNED RELAY SYSTEM CAPABLE OF PREVENTING THE INSTALLATION OF REMOTE EQUIPMENT AT A COAST RADIO STATION

摘要

PURPOSE: An integrate analog and digital-based digital selective calling(DSC)/very high frequency(VHF) unmanned relay system is provided to save costs required for installing and operating remote equipment and to reduce the occurrence of communication problems.;CONSTITUTION: A sea ship station(10) includes an analog transceiver implementing wireless communications based on an analog radio frequency(RF) signals. A first relay station(20) receives and converts the analog RF signals into digital RF signals and transmits the digital RF signals. The first relay station converts the digital RF signals into analog RF signals to be transmitted to the sea ship station. A second relay station(30) wirelessly transmits and receives the digital RF signals with the first relay station. A portable terminal(40) wirelessly transmits and receives the digital RF signals with the second relay station.;COPYRIGHT KIPO 2012