How do I filter my data points without using smoothdata?

I have 2 variables, t and y, which are both vectors. What I want to do is smooth the data so that, for example, if t is a 10x1 vector, it becomes a 5x1 vector comprising an average of the data points around it. How do I go about this without using the smoothdata function?

Thank you very much and kind regards,

Tom

[Bob Thompson]

I'm sure there's a better way, but you could do this manually using a for loop and interpolation.

t2 = linspace(t(1),t(end),5);
for i = 1:5;
    y2(i) = interp1(t,y,t2(i));
end

[Chad Greene]

Note: Interpolation without smoothing or lowpass filtering first could result in aliasing.

Answer 1

[Chad Greene]

What about movmean to smooth the data, then interp1 to pick out the 5 points you want?

[Thomas Nell]

Is movmean part of the signal processing toolbox??? I'm not allowed to use any functions from there

[Image Analyst]

No, it's part of base MATLAB. If you get help on any function, it will tell you what toolbox it's in, if any.

Answer 2

[Image Analyst]

You could use conv() to smooth y.

windowWidth = 5;
kernel = ones(1, windowWidth) / windowWidth;
smoothedY = conv(y, kernel, 'valid');  % conv() is in base MATLAB.

Do NOT smooth t, for obvious reasons.