Find indexes in time-series signal

Hi,

Im searching for x indexes of a given y value in a time-series signal.

What function should I use since the exact y value Im looking for sometimes do not exist?

Answer 1

[KSSV]

YOu may have a look on this example code:

% signal
x = linspace(0,2*pi)' ; 
y = sin(x) ;
% Get the x index for yi
yi =  randsample(y,1) ;
% Do interpolation 
xi = interp1(y,x,yi) ;
% GEt the index 
idx = knnsearch([x y],[xi yi]) ;
value = [xi yi]
iwant = [x(idx) y(idx)]

[KSSV]

YOu may also use this approach:

% signal
x = linspace(0,2*pi)' ; 
y = sin(x) ;
% Get the x index for yi
yi =  randsample(y,1) ;
% Check for abolute zero 
idx = abs(y-yi)<=10^-3 ;
yi
iwant = [x(idx) y(idx)]