1D Interpolation of a signal - beginners question

Hello everyone,

I have a beginners question about 1D interpolation of a signal. I have a system which is supposed to be sampled at 65 Hz but we found that the sampling rate is not constant and varies between 55-65 Hz. For further analysis I want to interpolate the data to have a signal with constant intervals between the data points. I used the following code but it seems not appropriate as it does not work properly.

y=signal(1,1).L1.Q(1:2982,1);    %this is an example signal 
ly=length(y);
x=0:ly-1;
lx=length(x);
li=ly\lx;
xi=0:li:lx;
yi=interp1(x,y,xi,'cubic');
plot(x,y,'o',xi,yi)

Could someone show me how to interpolate this signal so I get a signal with a constant sampling rate?

Thank you very much.

Answer 1

[Christoph Bauer]

y=signal(1,1).L1.Q;    %this is an example signal 
x=signal(1,1).L1.Elapsed;
xi=0:0.02:max(x);
yi=interp1(x,y,xi,'spline');
plot(x,y,'o',xi,yi)