detrend การใช้

• Generally speaking zero-padding would not be my first choice, as it attenuates power and also will induce spurious power at high frequencies unless you first detrend your signals.
• Since the RR data is an unevenly sampled data, another advantage of the LS method is that in contrast to FFT-based methods it is able to be used without the need to resample and detrend the RR data.