本文利用多周期同步测频法开发车速测量系统。文章分析了传统测频方法存在的 问题、采用多周期同步测频法实现整个测频范围内的等精度测量的原理、以及提高测量精度的方法,给出基于该方法的车速测量系统的软、硬件实现方式,并利用该系统进行实际测试。实验结果表明,该系统具有测量精度高、测量范围大、抗干扰性强等优点,适用于整车测试。 关键词:多周期同步测频法; 车速测量; 单片机 The Speed Measurement System Based on the Synchronous Multi-cycle Frequency Measurement CHEN Ling-feng, LU Qing-chun, WEI Hong-jun, NIE Sheng-fang (Automotive Engineering Department, Tsinghua University, Beijing, China, 100084) Abstract:In this paper, I design a speed measurement system based on the synchronous multi-cycle frequency measurement. Since there are some limitations with the traditional method, the paper analyzes how to realize the same precision in the entire survey scope and how to improve the measurement accuracy with the synchronous multi-cycle frequency measurement. The designing and the test experiment of the speed measurement system are offered. The result shows that the system runs well in high accuracy, wide scope, anti-interfering and is applicable to the speed measurement in Vehicle. Key words:Synchronous multi-cycle frequency measurement; the Speed Measurement System; Single chip 在评价汽车性能的整车测试实验中,车速测量是基础。通常,在整车测试实验中使用的 车速传感器的输出信号为频率信号,范围在10Hz~100kHz 内。因此,如何在10Hz~100kHz 范围内精确测量频率信号,是整车测试及车速测量中的一个重要问题。 传统车速测量,一般采用测频法或测周法。由于其方法本身固有的缺陷,传统车速测量 系统存在着当被测信号的频率变化范围较大时,精度比较低的缺点[1]。本文介绍了传统测量方法存在的问题,分析了多周期同步测频方法如何解决这一个问题,并且给出了用单片机实现的车速测量系统的具体方案,以及利用该系统进行测量的实际结果。