‘...the resample function is supposed to give you a rough signal with new data added.’
I am not certain of the specific syntax you are using with resample, and particularly what those variables are. However, the resample function only interpolates the input data to a new time vector (it does not actually ‘add’ anything else, and uses an anti-aliasing filter to prevent problems associated with the interpolation), usually defined by the sampling frequency argument and produces an accurate (not ‘rough’) interpolation. You are also using the 'spline' interpolation method, and that can have unpredictable results with step transitions such as exist at the beginning of your signal, and noise that exists in much of the rest of it. I always use the default 'linear' method, and have always been pleased with the results.
