Research And Design Of Mobile Terminal RF System Of The L Band Maritime Satellite

With the rapid development of mobile communication technology and constantly improvement of the people’s living standard, people are more strict with the performance of the mobile terminal equipment. Mobile terminal equipment offers many benefits to human survival, which is an integral part of human’s life and manufacture. It is the important role that make mobile terminal equipment has gradually become the focus of national research and development.China is a big marine county, our country attaches great importance to the utilization and development of marine resources,as a result, needing a lot of maritime satellite mobile terminal equipment. However, the equipment in China depend on imports, Due to the weakness of current maritime satellite mobile devices, they have large size and not too high performance.This article is based on the present situation to research and design the transmitter and receiver, put forward on the basis of MMIC device, adopting direct transform frequency and the vibration source integration technology to design a miniature、portable L-band maritime satellite mobile terminal radio frequency system, the system is consist of the reference frequency source with the vibration source, transmission and receive unit, communication control protocol and power supply. Using direct frequency conversion technique to modulation and up-conversion, demodulation and down-conversion, under the effect of frequency conversion, which makes the system structure more simple. Using the source of local oscillator integration technology, which using the same frequency as the PLL composites the reference source of transmit and receive local oscillator, to be sure that the local oscillator signal of the reference frequency source synchronous, thus realize the synchronization of carrier signal. This design is beneficial to reduce the distortion degree of the system, improving the performance of the system.This paper analysis the research status of the maritime satellite mobile terminal radio frequency system both in China and abroad, and then to put forward the subject structure and design plan; Then elaborates the theory of Involved QPSK technology;Then in view of the radio frequency transmitter and receiver module unit functionrealization carries on the research and design; Finally, this paper summarizes the work for the research haven done and raises the prospect of the future research work.