how to sampling the signal in order to match the two signal?

Question

Keshasni Earichappan 2021-8-14

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回答： Star Strider 2021-8-15

Hi.i am having trouble to set both data (mc & torque) on the same time axis.MC-voltage signal need to sampled at 5 kHz and low-pass filtered with a cutoff frequency 10 Hz in order to match with the torque(maybe).Basically,I need to match the two different time series into one same time series.Hope anyone can help me to figure it out.Thanks in advance

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dpb 2021-8-14

Look at resample in Signal Processing Toolbox...

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Answer 1

Star Strider 2021-8-15

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https://ww2.mathworks.cn/matlabcentral/answers/898342-how-to-sampling-the-signal-in-order-to-match-the-two-signal#answer_767567

在 MATLAB Online 中打开

The first 2 column in ‘TORQUE’ are missing, so they are removed here.

% C1 = readcell('https://www.mathworks.com/matlabcentral/answers/uploaded_files/711992/TORQUE.txt')

% nrmissing = [nnz(ismissing([C1{:,1}])) nnz(ismissing([C1{:,2}])) size(C1,1)]

T1 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/711992/TORQUE.txt', 'VariableNamingRule','preserve');

T1 = removevars(T1,{'Var1','Var2'})

T1 = 7967×2 table

TIME TORQUE ____ ______ 0 0 10 0.7 20 1.1 30 6.5 40 6.5 50 6.4 60 6.5 70 6.4 80 6.1 90 6.1 100 6.4 110 7.1 120 7.9 130 8.3 140 7.9 150 8

T2 = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/712562/MC.txt', 'VariableNamingRule','preserve')

T2 = 90483×2 table

Time MC[v] ________ ______ 0 1.8297 0.000999 1.8289 0.001998 1.8297 0.002997 1.8297 0.003996 1.8305 0.004996 1.8289 0.005996 1.8297 0.006997 1.8313 0.007996 1.8305 0.008995 1.8281 0.009994 1.8297 0.010995 1.8305 0.011994 1.8305 0.012995 1.8297 0.013994 1.8297 0.014993 1.8305

Fs = 100; % Resample To 100 Hz Sampling Frequency

[TORQUEr,T_TIMEr] = resample(T1.TORQUE, T1.TIME, Fs);

[MCvr,V_TIMEr] = resample(T2.('MC[v]')-mean(T2.('MC[v]')), T2.Time, Fs);

MCvr = MCvr + mean(T2.('MC[v]'));

figure

subplot(2,1,1)

plot(T_TIMEr, TORQUEr)

grid

xlabel('t')

ylabel('Torque (Resampled)')

subplot(2,1,2)

plot(V_TIMEr, MCvr)

xlabel('t')

ylabel('MC[v] (Resampled)')

grid

They both have the same 100 Hz sampling frequencies, however they retain significantly different time vectors.

.

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Answer 2

Sulaymon Eshkabilov 2021-8-14

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/898342-how-to-sampling-the-signal-in-order-to-match-the-two-signal#answer_766992

在 MATLAB Online 中打开

% They perfectly match as you can see the plot below.

MC = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/711992/MC.txt');

Torque = readtable('https://www.mathworks.com/matlabcentral/answers/uploaded_files/711992/TORQUE.txt');

plot(MC.TIME, MC.TORQUE, 'bx', Torque.TIME, Torque.TORQUE, 'r'), legend('MC','Torque')

% If you need to resample them then, apply resample()

% See here: https://www.mathworks.com/help/signal/ref/resample.html

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Sulaymon Eshkabilov 2021-8-15

Yes, it might be. I've written the code on online here and executed it, rightaway. I have not used a desktop matlab since my matlab license was not activated.

Keshasni Earichappan 2021-8-15

hi @Scott MacKenzie & @Sulaymon Eshkabilov....sorry i had attached the wrong MC.txt file jn..here i have attached the updated one..I need to match the two different time series into one same time series(sampling period).Is it possible? :)

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