Design And Realization Of The Weather Facsimile And NAVTEX Combination Receiver

Weather fax receiver used to receive meteorological information is essential in a ship at sea, and NAVTEX receiver is an important part of the GMDSS. Both have played an indispensable rolefor the safety of ships sailing in the sea. Currently, weather fax diagrams are received using weather fax receiver, while NAVTEX receiver receives warning information separately. With the development of the technologies, weather fax and NAVTEX combination receiver has become a trend. However, related research on the combination receiver has not been conducted at home. In addition, with the development of semiconductor technology, the receiver is evolving to highly digitized direction. Based on the current development status, the paper is beginning to study on the combination receiver.In this article, the receiver is divided into three parts in order to be convenient for modular design, followed by the front panel module, the digital controller module and the human-computer interaction module. In addition, except for the local print graphic display functions, the system can realize the data share with computers via Ethernet.The front panel module is used to receive weather fax and NAVTEX signals, which are demodulated to the baseband modulation signal latter. Through the AD converter, the analog signal of the baseband signalcan be converted to the digital signal. The front panel module includes the filter circuit, the mixercircuit and the local oscillator design etc. In this design,dual-core digital controller is used to replace the traditional DSP + dual-port RAM + ARM solutions, which simplifies the hardware design and improves the digital level. One of the coresmainly completes the digital FSK demodulation, while the other core controls the peripheral devices. The digital controller module includes the memory design, the network design and the bootloader. Human-computer interactionmodule is designed for LCD display,the thermal printer driver and key input device.After the completion of thehardware design, the software design and actual test for each module are conducted, and the test results show that FATFS file system and UIP network protocol stack have achieved the desired result, also the LCD can display images and text.Finally, the system joint debug is also conducted and the results indicate that the systerm can achievethe basic function.