Seperate high and low frequeny components from signal.

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Rajan 2014-10-9

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编辑： Rajan 2014-10-10

Hello

Please help me in separating low and high frequency components of signal(Time series data) recorded from a biological system. For data please refer to the column 2 of attached file.

The objective of my work is to select a random frequency threshold and then plot separate time series for low and high frequency components.

Thank you

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Rajan 2014-10-10

Please check again I have updated the file.

Star Strider 2014-10-10

When I did a FFT of your data (column 1), there was only noise above about 5 Hz.

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回答（1 个）

Image Analyst 2014-10-10

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编辑：Image Analyst 2014-10-10

在 MATLAB Online 中打开

You can put this in a loop to extract from element 1 to the point and from the point to the end. Fit each segment to a line and record the slope. Plot the slopes and see where it starts to deviate from a constant. Something like (totally off the top of my head and untested)

for k = 1 : length(signal)
  leftSignal = signal(1:k);
  rightSignal = signal(k:end);
  % Now fit
  coeffs = polyfit(1:k, leftSignal, 1);
  leftSlopes(k) = coeffs(1);
  coeffs = polyfit(k:length(signal), rightSignal, 1);
  rightSlopes(k) = coeffs(1);
end
plot(leftSlopes, 'b-', 'LineWidth', 2);
plot(rightSlopes, 'r-', 'LineWidth', 2);
grid on;
legend('Left Slopes', 'Right Slopes');

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Image Analyst 2014-10-10

The signal I was talking about was the log of the frequency domain signal, NOT the time domain signal. So it should still work once you use the proper signal.

Rajan 2014-10-10

编辑：Rajan 2014-10-10

Thanks for your reply.

Is there any method by which I can directly filter the original time series data? Because my final objective is to separate high and low frequency components from original data. And plot two different time series Where each corresponds to different slops.

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