A monitoring process and system

摘要

A system for monitoring at least one moving object such as a vehicle includes: at least transmitter for transmitting optical signals modulated at respective modulation frequencies; at least one receiver adapted to detect at least one of the received optical signals on the basis of the modulation frequencies, and a means for detecting at least one of making and breaking of the at least one detected signals due to movement of the object to determine at least one parameter of the object. The receiver can include a sensor and an input circuit for converting at least one of the received optical signals to an electrical signal and an analog to digital converter for digitizing the electrical signal. The system can include a digital signal processor for demodulating the digitized signal from each of the receivers to provide output data representative of the at least one of making and breaking of the at least one of the detected optical signals.