各种微波电路部件正日益广泛地应用于各种通讯设备中,三次交调特性的测量是对部件各种特性测量的重要环节。特别是对于各种低噪声前端,往往要测量它们小信号时的交调特性,由于仪表灵敏度的限制或由于背景噪声的影响,三次交调这个参数用常规方法往往测不准或根本无法测出。下面介绍一种用外推法测量微波低噪声部件三次交调特性的方法。 众所周知,理想的线性电路输入输出信号的频谱是不变的,也就是说信号通过这种部件并不会产生新的频率分量。但是由于实际电路总是或多或少的带有非线性,因此当有两个以上的载波频率输入到部件中后,其输出端除了输入频率分量之外,还会出现一系列的组合频 A variety of microwave circuit components are increasingly used in a variety of communications equipment, the third intermodulation characteristics of the measurement of various components of the measurement of an important part. Especially for a variety of low-noise front-end, often to measure their small signal intermodulation characteristics, due to the limitations of the instrument sensitivity or due to the impact of background noise, the three intermodulation of this parameter is often measured using conventional methods are not allowed or measured . The following describes a method of extrapolation to measure the third-order intermodulation characteristics of microwave low noise components. It is well known that the spectrum of an ideal linear circuit input and output signal is constant, that is to say that the signal passing through such a component does not generate a new frequency component. However, since actual circuits are always more or less non-linear, when there are more than two carrier frequencies input to the part, a series of combined frequencies will appear at the output ends besides the input frequency components