【摘要】 对电磁波在传输线中的测长理论进行了分析,设计了一种电磁波反射测长系统。该系统由单片机控制,使用锁相倍频技术产生1200 MHz高频参考时钟,采用脉冲计数原理,实现对发射脉冲与反射脉冲时间间隔的精确测量,在波速已知的情况下,得到被测电缆长度。实验结果表明,该系统具有较高的精度,可以被广泛的应用于电缆长度测量领域。更多还原

【Abstract】 The length measurement theory of electromagnetic wave in transmission line was analyzed and a cable length measuring system based on the reflection of electromagnetic wave was designed.The system was controlled by single-chip microcomputer to produce 1 200 MHz high frequency reference clock using phase lock and multiple frequency technique.Based on pulse counting principle,the high precision time interval of the emitted pulse and the reflected pulse can be measured.In the circumstances of known wave velocity,the cable length can be obtained.The experimental results confirmed that the system has high accuracy and can be widely used in the field of cable length measurement.更多还原