论文部分内容阅读
衰减是微波测量中的基本被测量之一。目前广泛采用的测量方法是代替法。根据标准衰减器的不同,代替法可分为微波代替法、中频代替法和低频或直流代替法。中频代替法虽有许多优点,但要求频率稳定度较高,并且变频的直线性限制了可以精确测量的最大衰减约为50分贝,低频代替法也因晶体检波律的限制,可测的最大衰减约为40分贝。现有的微波代替法是串联代替法。在这个方法中,标准衰减器和被测衰减器串联;测量时,调节两个衰减器使其衰减量的和恒为常数,输出指示保持不变,因此不受检波指示系统的线性限制,对能源的频率稳定度要求不高,可测衰减达70分贝;
Attenuation is one of the basic measurements in microwave measurements. Currently widely used measurement method is to replace the law. According to the standard attenuator, the substitution method can be divided into microwave method, IF method and low frequency or DC instead of law. Although the IF substitution method has many advantages, but requires a higher frequency stability, and the linearity of the frequency conversion limits the maximum attenuation can be accurately measured about 50 decibels, low frequency substitution method is also due to crystal detection law limits, measurable maximum attenuation About 40 dB. The existing microwave substitution method is a tandem substitution method. In this method, the standard attenuator and the measured attenuator are connected in series. During the measurement, the two attenuators are adjusted to make the sum of the attenuation constant and constant. The output indication remains unchanged, so it is not limited by the linearity of the detection indication system, Less demanding on the frequency stability of energy, measurable attenuation of 70 dB;