The No.41 Research Institute of CETC used the OE1201 lock-in amplifier from Sine Scientific Instruments to extract the weak signal from the antenna in the terahertz spectrometer. When developing the terahertz spectrometer, the No.41 Research Institute of CETC used the OE1201 digital lock-in amplifier developed by Sine Scientific Instruments, tested the stability of the terahertz detection signal, and the stability and signal-to-noise ratio met the test requirements, which can replace the Stanford SR830 and meet the requirements.