一种简易数字信号传输性能分析仪的设计  

Design of a simple digital signal transmission performance analyzer

作　　者：龙光利[1] 唐军山 蓝晓东 

机构地区：[1]陕西理工学院物理与电信工程学院,陕西汉中723003 [2]陕西中烟工业公司汉中卷烟厂,陕西南郑723102

出　　处：《陕西理工学院学报（自然科学版）》2013年第4期20-24,共5页Journal of Shananxi University of Technology:Natural Science Edition

摘　　要：设计了一种简易数字信号传输性能分析仪,由数字信号发生器、低通滤波器、伪随机信号发生器、数字信号分析电路、信号扫描电路等组成。通过单片机控制AD9851产生频率可变方波作为数字信号发生器时钟,使用模拟运算放大电路设计低通滤波器,在QUARTUSⅡ环境下设计数字信号发生器、伪随机信号发生器和数字信号分析电路,编译仿真通过后下载到现场可编程门阵列芯片EP2C8Q208C8N中,用锯齿波电路产生扫描信号。测试结果表明:该分析仪数字信号发生器数据率为10～100 kbps,按10 kbps步进可调,误差小于1%,输出为曼彻斯特编码;截止频率为100,200,500 kHz的3个低通滤波器,误差小于10%,带外衰减小于40 dB/十倍频程,通带增益在0.2～4.0范围内可调;模拟信道噪声的伪随机信号发生器数据率为10 Mbps,误差小于1%;输出信号峰峰值为100 mV～TTL电平,误差小于10%;通过示波器X-Y模式可显示眼图。A simple digital signal transmission performance analyzer is designed,which consists of a digital signal generator,three low-pass filter,a pseudo-random signal generator,a digital signal analysis circuit and a signal scanning circuit.A variable frequency signal is generated by MCU controlling AD9851 chip as digital signal generator clock.The low-pass filter is designed by using analog operation amplifier circuit,the digital signal generator,the pseudo-random signal generator and the digital signal analysis circuit are designed on the platform QUERTUEⅡ,it downloading to the FPGA chip EP2C8Q208C8N when compiled and wave formed,a scanning signal is generated by saw tooth wave circuit.The test results show that the data rate of the analyzer digital signal generator is 10 ～ 100 kbps according to 10kbps adjustable step,the error less than 1%,the output the Manchester code;the cut-off frequency of three low-pass filter 100 kHz,200 kHz and 500 kHz,the error less than 10%,stop band attenuation less than 40 dB / ten octave,and passband adjustable gain ranges 0.2 ～ 4.0;the data ratio of pseudorandom signal generator which simulate noise of channel is 10 Mbps,the error less than 1%;the output signal is 100 mV ～ TTL level,the error less than 10%;it can display the eye diagram through the oscilloscope X-Y mode.

关 键 词：数字信号发生器 伪随机信号发生器 低通滤波器 

分 类 号：TN919.64[电子电信—通信与信息系统]