说明：  低频数字式相位测量仪； 此系统由相位测量仪、数字式移相信号发生器和移相网络三部分组成。为使系统更加稳定，使系统整体精度得以保障，本电路两块T89C52为核心控制器件分别控制相位测量、数字式移相信号发生,在数字式移相信号发生部分采用了锁相技术、CPLD等技术, 使输出波形精度大大提高，并可对频率自动校验，提高频率稳定性。
(low-frequency digital phase-measuring instrument; This system consists of phase-measuring instrument, digital phase shifting generator and phase three network components. To make the system more stable, the overall accuracy of the system can be protected, the two T89C52 circuit control devices at the core respectively phase measurement control, digital believe the shift occurred, the digital shift occurred some believe that the use of lock-in technologies, such as CPLD technology, the output waveform accuracy greatly improved, and can automatic calibration frequency, frequency stability.)