摘要
在分析水位远程测量特点的基础上,给出了远程水位测量和数据传输系统结构,将水位传感器输出的电压信号通过LM331转换成频率信号.利用V/F转换代替A/D转换和单片机处理芯片,通过变压器对变化的频率信号升压实现远距离传输,监控管理站计算机对频率的计数实现水位计算,分辩率达到cm级,采用MT8880作为DTMF的编、解码实现管理站和各水位监测点之间的地址译码.运用两级防雷、直流供电和长距离悬浮线通信技术提高系统的可靠性.应用DSP技术,计算接收频率的能量,快速傅里叶变换(FFT)计算频点附近的DFT的值,实现对多路DTMF信号的检测.
A long-distance water-level measuring and data transmission system is put forward. The output voltage signal of water level sensor is changed to frequency signal by LM331 first. Then with V/F conversion instead of A/D conversion and using chip microcomputer, long-distance transmission is achieved after boosting the changing frequency signal by transformer. The monitoring computer calculates the water level by frequency counting, and the resolution can reach centimeter level. The system adopts MT8880 series as DTMF coding and decoding to realize the address decipher between the administrative station and each water level monitoring point, and applies two-grade thunder preventing technology, direct current supply and the long-distance communication technology based on the suspended line to enhance the system＇s reliability. Finally multi-channel DTMF signal detection is realized by applying DSP technology to calculate the energy of the receiving frequency and by adopting FFT to obtain DFT values near the frequencies.
出处
《测试技术学报》
2008年第4期296-300,共5页
Journal of Test and Measurement Technology
关键词
数据传输
V/F转换
DTMF信号
频率计数
水位测量
： data transmission
V/F conversion
Dual Tone Multi Frequency（DTMF） signal
frequency counting
water-level measurement
