VSAT上变频器的杂散、互调干扰分析与电路的优化设计

Analysis on the Spurious and Intermodulation Products and Circuit Optimization of VSAT Up-converter

为保证卫星通信VSAT系统内和系统间良好的电磁兼容性，必须严格限制带外和寄生辐射．本文分析了VSAT上变频器来散、互调干扰等的主要来源，包括信频与本振谐波组合干扰分量，多载波之间的互调分量等。在此基础上提出了旨在减小杂散电平的电路优化设计方法，其中包括在满足上变额总增益要求的条件下，电路各级增益或衰减的配置、本振功率的确定等，最后给出应用实例。

In order to assure good electromagnetic compatibility between and within satellite communication VSAT systems. It is necessary to significantly reduce the outside band and spurious radiations. In this paper, two types of spurious products of VSAT up-converters that consist of single-tone or harmonic intermodulation and multiple or two-tone intermodulations are analysed. On this base, the optimization of circuits for decreasing the spurious level including determination of stage gain. loss and LO power is proposed. Finially, the application example is given.