Laser heterodyne interferometric signal processing method based on rising edge locking with high frequency clock signal.

Optics express

PubMedID: 23481996

Zhang E, Chen B, Yan L, Yang T, Hao Q, Dong W, Li C. Laser heterodyne interferometric signal processing method based on rising edge locking with high frequency clock signal. Opt Express. 2013;21(4):4638-52.
A novel phase measurement method composed of the rising-edge locked signal processing and the digital frequency mixing is proposed for laser heterodyne interferometer. The rising-edge locked signal processing, which employs a high frequency clock signal to lock the rising-edges of the reference and measurement signals, not only can improve the steepness of the rising-edge, but also can eliminate the error counting caused by multi-rising-edge phenomenon in fringe counting. The digital frequency mixing is realized by mixing the digital interference signal with a digital base signal that is different from conventional frequency mixing with analogue signals. These signal processing can improve the measurement accuracy and enhance anti-interference and measurement stability. The principle and implementation of the method are described in detail. An experimental setup was constructed and a series of experiments verified the feasibility of the method in large displacement measurement with high speed and nanometer resolution.