|
|
马上注册，结交更多好友，享用更多功能，让你轻松玩转社区。
您需要 登录 才可以下载或查看，没有账号？注册
x
请教关于读入外部数据进行眼图分析的过程的问题
使用的是MATLAB2012A的环境
现在有2组数据，clk与data
时钟的频率是400MHz（周期是5ns，脉宽是2.5ns），取样频率5ps，此时采集时间为500ns，共有数据点10万个
时钟沿在每个码元的中间进行触发，时序关系是间隔2.5ns
但是使用“commscope.eyediagram”进行测量时提示错误：
Warning: The eye diagram does not have enough data. Analysis results may not be
accurate. To improve accuracy, enter more data using the UPDATE method.
> In commscope.eyemeasurements.analyze at 70
In commscope.eyediagram.analyze at 85
In Untitled at 24
Error using calcEyeCrossingTime (line 67)
The ANALYZE method cannot determine crossing times. Check measurement setup values in
the MeasurementsSetup property. Also, the collected data may not be valid. See
documentation for description of valid eye diagrams.
Error in commscope.eyemeasurements/analyze (line 85)
calcEyeCrossingTime(this,...
Error in commscope.eyediagram/analyze (line 85)
this.Measurements.analyze(this);
Error in Untitled (line 24)
analyze(eyeObj);
怎么理解“The eye diagram does not have enough data”，按照时钟数据，波形有100个，为何还不够？
而且读入clk后显示的眼图感觉也不太对
请熟悉眼图的朋友帮分析一下错误的地方在哪里
简单的代码如下：
clear
close all
%filename ='F:\clk.txt';
filename ='F:\data.txt';
fid=fopen(filename,'r');
[code,count]=fscanf(fid,'%f',100000);
plot(code);
% Create an eye diagram and display properties
eyeObj = commscope.eyediagram(...
'SamplingFrequency', 200000000000, ...
'SamplesPerSymbol', 500, ...
'SymbolsPerTrace',2,...
'MinimumAmplitude', 0.4, ...
'MaximumAmplitude', 1.4, ...
'PlotTimeOffse',0,...
'PlotType','2D Colo',...
'ColorScale', 'log') %#ok
update(eyeObj, code);
title('Noisy NRZ signal');xlabel('Time (sec)');ylabel('Amplitude');grid on;
analyze(eyeObj);
eyeObj.Measurements
clk.rar
(239.37 KB, 下载次数: 29 )
data.rar
(232.47 KB, 下载次数: 21 )
|
|
/2 
eetop公众号
创芯大讲堂
创芯人才网
发表于 2012-7-4 18:17:30
