摘 要：对于现在更高的数据速率和串行总线，用户需要专用工具来设计、调试和验证设计。示波器噪声、触发器抖动和探针保真度都可能影响用户对低电压差分信号的测量。时钟信号一般嵌入在用户数据中，该数据可能经过8b/10b编码，因此调试这种信号需要使用智能的示波器。当设计完成后，用户必须进行一致性测试，这意味着要在短时间内进行很多复杂的测试。标准示波器对此无能为力。本设计通过线性移位寄存器发生器产生m序列的数字信号和伪随机信号，数据率误差绝对值均≤１%，其中数字信号发生器采用了曼斯特编码，时钟数据率在10~100kbps内以10kbps步进可调，伪随机信号数据率为10Mbps。两路信号的时钟，均由序列的FPGA产生。低通滤波器由无限增益多路反馈二阶低通滤波电路实现。两路信号由高速运放AD811进行信号叠加后输入示波器，显示数字信号的信号眼图。数字信号分析仪所采用的时钟信号，通过开关切换，可使用数字信号发生器的时钟信号，也可以使用FPGA及其外围电路提取的同步时钟信号。本系统由两部分组成：1.数字信号发生器同时通过三个低通滤波器和一个伪信号发生器用来模拟传输信道。2.乘法器和三个低通滤波器所组成的数字信号分析电路，提取有效数字信号。
关键字：m序列发生器；同步信号提取；曼彻斯特编码
Abstract:This topic is the widening project of " low-temperature wind driven generator basing on Cortex-M3 processor ".The wind driven generator in the original project has a bad field working environment since the monitoring station is remote from the wind generator. The way of direct transmission of the signal will cause a certain degree of waste and inconvenience, while wireless transmission can make up the above shortcomings.
The system described in this passage has been successfully completed designed and produced .The system is a embedded temperature data detection system that made up of SCM AT89S52 and RFIC nRF905 and several other modules. The design of the temperature detection system adopts advanced digital temperature sensor.
This paper describes the system's specific work flow in detail, and on this basis gives out the workflow diagram of RFIC and the structure chart of hardware design of the wireless data detection part and wireless host part. System software programming adopts the C language.
The system has passed the lab test. The test results show that the temperature measurement accuracy of the whole system reaches ± 0.5 ℃, Measurement accuracy of the instrument system 0.5 Level and the wireless transmission range goes up to 300 meters, and the system performance stay stable within 300 meters . The system also has good resistance to electromagnetic interference .So far the performance of the entire system has completely met the design expectations.
This system is not only for " low-temperature wind driven generator basing on Cortex-M3 processor " system, but also can be used for remote sensing, remote control, wireless meter reading, industrial data acquisition and home automation and other fields. Have some practical value.
Key words: temperature; wireless transceiver; SCM; sensor
