Noise Rejection Using Variable-Height Timing-Window Technique for Pulse Signals With Variable S/N Ratio

This paper proposes a novel technique, known as the variable-height timing window (TW), for rejecting noise in an active source detection system. The basic principle of a TW and a methodology of using a microprocessor to dynamically adjust the height of the TW are presented. This variable-height TW technique has been applied to a laser-based detection system (LBDS) for detecting vehicle information on highways. Field-test results of the LBDS showed that the adaptive nature of the proposed TW approach can effectively reject various types of noise under different environmental conditions. This variable-height TW technique can also be used to remove out-of-window noise and suppress the effect of in-window noise in various field environments in which the signal/noise (S/N) ratio is variable.