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Ultrashort wave aviation communication, pure voice radio transmit voice information is not only inefficient, unable to transmit more complex information and data, and error-prone. While retaining voice communication, ultrashort wave aviation communication will focus on the transition to the data communication system to increase the air-ground communication capacity, expand coverage of communication to improve the connectivity and interoperability of communication, interoperability performance. Technology development and engineering practice, the use of voice communication radio to transmit tactical data and air traffic control data, to extend the functionality of the original voice radio, making it both as an aviation voice communications, and support data transfer / number of dual-use radio stations, both in the technical or practical effect will be a good effective. From application analysis, analysis of aeronautical communications transmission model and channel characteristics, factors affect the communication distance and communication quality judgment standard, the ultrashort wave aviation communication transmission radio developed as an opportunity, around the effectiveness of aeronautical data communication reliability and timeliness of the of ultrashort wave aviation conventional voice radio carried out a detailed analysis of the key technology improvements to the data radio. Given the overall architecture of the composition of the internal data transmission radio signal flow and interface timing, focus on secondary modulation technique the MODEM module and receive transmit channels detailed implementation program. MODEM hardware platform, functional distribution, signal processing, and software processes the same time, a detailed description and analysis of, and adaptation receiver front-end of the second modulation technique AGC controlled IF filter, FM modulation and demodulator, broadband linear amplifier, transceiver switches and other hardware improvements. Focuses on FM-PSK secondary modulation and demodulation technology advantage in the channel bandwidth utilization, calculated two signal quality of the FM-PSK, accounting required RF signal level to meet the bit error rate requirements. Around the FM-PSK secondary modulation of the implementation, further analysis of the ability of error correcting codec on a system frame format is designed, and the carrier and symbol synchronization scheme, a clear key improvements of the receive and transmit channels, and the receiver is given in the text detailed circuit program and transmit channels. In the study of the subject, the use of a large number of technical analysis, theoretical arguments, experimentation and simulation, experimental verification than testing and other means of transmitting power, the transceiver conversion time fluctuates within the passband, the transmitter and the receiver delay, voice sensitivity digital transmission sensitivity, residual error rate indicators detailed test, the final test results and test conclusions. Laboratory tests and actual field test flight with better sensitivity and communication of digital transmission distance, when to satisfactory Diaobao rate better signal quality, fully meet the project using the communication distance and communication quality requirements.
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