Help to plot the LED Characteristic Curve

Question

adriane duarte 2021-9-10

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1450939-help-to-plot-the-led-characteristic-curve

评论： adriane duarte 2021-9-11

I am trying to plot the LED characteristic curve, but I am not getting the correct curve.The theoretical curve is below.

The curve I'm finding is this. A little different than expected.

Someone could help me with what I'm wrong. I'm submitting my code below.

% LED information
Vt = 0.5; 
Is = 0.5; 
% LED model
K = 0.5; 
imax = 0.5; 
threshold = 150;
sigmaV2 = (imax./threshold).^2;
% number of bits
L = 1e4;
SNRdB = 40;
% Signal-to-Noise Ratio Lin.
SNR = 10.^(SNRdB/10); 
r = 10.^(SNRdB/10);
% signal standard deviation (power)
sigmaX2v = SNR.*sigmaV2;
% Maximum number of iterations for a single SNR
max_run = 100;
for sk = 1:length(SNRdB)
    
    for tk = 1:max_run
        s = linspace(0,100,10000); % input
        s1 = s.';
        stdS = std(s1);
        X = zeros(1,4.*L);
        X(2:2:end) = [s1; conj(s1(end:-1:1))]; 
        xTD = ifft(X);
        xTD = (sqrt(sigmaX2v(sk))).*xTD./std(xTD);
        xx = xTD;
        ind = find(xTD < 0);
        xx(ind) = zeros(size(ind));
        ss = xx;        
        iLED = Is.*(exp(ss./Vt) - 1); 
        xLED = iLED./((1 + (iLED./imax).^(2.*K)).^(1./(2.*K))); 
        
        y = xLED; 
        
        Nframe = length(y);
        Xhat = (fft(y)+10);
        Shat = Xhat(2:2:Nframe/2);
        Shat = stdS.*Shat./std(Shat); 
        Y = Shat; % output
    end
end
plot(s1,Y)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Sulaymon Eshkabilov 2021-9-10

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1450939-help-to-plot-the-led-characteristic-curve#answer_784954

在 MATLAB Online 中打开

The answer in signal-to-noise ratio value, e.g:

SNRdB = 20; % Gives a nice looking one!

3 个评论
显示 1更早的评论隐藏 1更早的评论

Sulaymon Eshkabilov 2021-9-10

Your obtain curve shape changes because of the SNR value. Thus, whichever value is your actual value for simulation that would be appropriate. You can simulate your code with different values of SNR and see how SNR inluences your curve shape.

adriane duarte 2021-9-11