| 摘要 |
PURPOSE: A non-contact vehicle speed detector is provided to accurately measure the speed by generating the delay signal with a pulse width for the corresponding time not to be measured. CONSTITUTION: A non-contact vehicle speed detector includes a laser transmission unit, a laser reception unit, a digital counter unit, a remaining time detection unit, a pulse expansion unit, an analog-to-digital converting unit(16) and a controller(1). The laser transmission unit emits the laser signal to the moving object. The laser reception unit receives the laser signal reflected from the moving object. The digital counter unit counts the reference clock to measure the time between the emitting time and the feedback time of the laser signal. The remaining time detection unit generates the delay pulse by delaying the reference clock during the remaining time. The pulse expansion unit expands the delay pulse corresponding to the remaining time. The analog-to-digital converting unit converts the expanded pulse into a digital signal and integrates the digital signal during a predetermined time. And, the controller determines the final speed of the moving object by summing the measuring time of the digital counter unit and the remaining time measured by the analog-to-digital converting unit.
|
