| Modern wireless communication is the fastest growing area of development communication a means of communication,in all areas of society today has been a very wide range of applications;where VHF communication equipment for research work,either for civilian or military,have a very important and far-reaching significance.This paper focuses on the U/V band(225?800MHz)BVR communication device a universal broadband transmitters,including pre-demonstration program,the overall design of the circuit,the development of the sub-circuits,as well as whole FBI again.This study has the following main characteristics:1)In order to achieve broadband emission,direct modulation transmitter plus double-conversion design;focus on in terms of the frequency of high-frequency selection,gain index allocation,while also taking into account the spurious frequency selection and optimization requirements,factors considered spurious and harmonic interference;reasonable for the overall circuit design,and preferably each functional module components,completed the optimization of electromagnetic compatibility design and circuit design;2)In order to meet the requirements of the system in the transmitter spurious and harmonic suppression,and taking into account the complexity of the design of the transmitter and adjustable resistance,etc.,of the transmitter the entire band is divided into three sections.3)Designed a high-precision transmission level detection and control scheme optimized transmitter amplitude-frequency characteristics,enhance the practical performance of the product.In this paper,after the design of the transmitter discussed were again involved in all areas of the frequency synthesizer,local oscillator,frequency converters,filters of each module,a detailed description and analysis;Upon completion of the whole of the FBI given on all aspects of the test results,and the final test results are analyzed;results indicate that the developed prototype to achieve the desired design requirements. |
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