Calibration and Equalization for the Measurement Channels of a Photoelectric Testing System with Intersecting Detection Areas

There are usually non-equilibrium transmission characteristic among the measurement channels of a photoelectric testing system with intersecting detection areas, and it will lead to a poorer measurement result provided that they are not properly calibrated and equalized. To improve the measurement accuracy of the system, this article presents an original calibration & equalization method to effectively restrain the effect of the non-equilibrium transmission characteristics. The measurement principle of this system is described in detail. Then, main transmission characteristic of the measurement channel is analyzed, and a calibration model is established and the requirements of its calibration signal are considered. Next, the equalization principle of measurement channel is studied, and then a compensating network is developed to perform an iterated algorithm to equalize the measurement channels. Through semi-physical simulation, the results show that an experiment platform is developed to generate several parallel calibrated signals with quasi–delta, and this can obtain the key characteristic (i.e., delay time) of the measurement channels. Furthermore, the transmission delay difference between any two measurement channels is below $0.5~\mu \text{s}$ through iterated equalization. Consequently, the proposed calibration and equalization method can effectively decrease the systematic error of the testing system.