Design of Phase-Shift Signal Generator with High Precision Used for Particulate Detection

Abstract

Particulate detection, which is based on lock-in amplifier technology, requires a phase-shift signal generator with wide frequency range and high phase shift precision. Since the current phase-shift signal generator has a deficiency of low precision in high frequency range, the author designed a phase-shift generator which adopts direct digital frequency synthesis technology, and expresses hardware design principles of the system. This paper focuses on the design of hardware and software concerning high precision phase shift and amplitude closed-loop control. The experimental results indicate that the output signals have a high accuracy in phase difference, frequency and amplitude under a wide frequency range and this system achieves the requirements of particulate detection.