two-input subtracter

According to the frequent malfunctions in input parts of the superhet measurement instrument met in the repairing work,this paper described the structures of the input attenuator and 1st mixer,it analyzed the reasons that may be destroyed in detail,and gave the removing methods.

本文以维修工作中遇到的超外差式测量设备输入端常见故障为线索,介绍了其中输入衰减器和第一混频器的结构,并详细分析了可能造成其烧毁的原因与排除方法。