本文提出一种利用低频锁相放大器测量高频信号的混频-锁相检测技术.将这一技术用于低阻半导体器件的结电容测量,获得了满意的结果.测量装置的工作频率在400千赫～4兆赫间连续可调,可以测出结电阻低到50欧姆的器件的结电容.文中列出了碲镉汞光电二极管结电容的测量结果. In this paper, we propose a mixer-lock detection technique for measuring high-frequency signals using a low-frequency lock-in amplifier. This technique is used to measure the junction capacitance of low-resistance semiconductor devices with satisfactory results. The operating frequency of the measuring device is between 400 Continuously tunable from kilohertz to 4 megahertz, the junction capacitance of devices with junction resistance as low as 50 ohms can be measured.The measurement results of the junction capacitance of a CdTe photodiode are listed in this paper.