一种模拟信号的远距离隔离传输方法

工业现场中，有时需要将传感器转换后的模拟信号传到控制中心进行模数转换后再送到控制器进行处理。本文提出了一种适用于高压环境下远距离传输模拟信号的方法：利用AD650构成压频和频压转换电路，先将模拟信号经压频电路线性变成一定频率的方波脉冲列，并经光纤传输到远处的控制中心。在控制中心再将脉冲列送入频压转换电路还原成电压信号，最终送入数模转换芯片转换成数字信号送入控制器进行处理。文中详细设计了电路结构和参数，并进行了实验。实验结果表明所设计方案可以有效地远距离传输模拟信号，既无衰减，又有良好的抗干扰能力。

One Method to Isolated Transport Analog Signals for Long-distance

In the industrial field, sometimes need to transport analog signal converted by sensors to control center for AD conversion and then send to the controller for processing. This paper presents an approach for transmission analog signals under the circumstance of high voltage: using AD650 to construct voltage / frequency circuit and frequency/voltage conversion circuit, the voltage / frequency circuit first linearly converts the given analog signals to a square-wave pulse train with some frequency, and the optical fiber transmits it to distant control center. In the control center the pulse trains into a frequency to voltage conversion circuit are restored to voltage signals, and finally into the AD chip to be converted to digital signals, which are put into the controller for processing. The circuit structure and parameters were designed in detail and some experiments were carried on. The experimental results show that the scheme can effectively transport an analog signal without attenuation for long distance, with good anti-interference ability as well.