Remove the riding waves in FM signals

Remove the riding waves in FM signals generated by Empirical AM-FM Decompisition method

The Riding Wave has a defination: In a signal, if there exists a local minimum greater than zero between two successive local maxima, or if there exists a local maximum less than zero between two successive local minima, the segment between these two successive local maxima (or local minima) is called a riding wave.
The function riding_wave.m is designed to eliminate the riding waves in FM signals producted by Empirical AM-FM Decompisition method.
Reference:
[1] Yang Z, Yang L, Qing C, et al. A method to eliminate riding waves appearing in the empirical AM/FM demodulation[J]. Digital Signal Processing, 2008, 18(4): 488-504. https://doi.org/10.1016/j.dsp.2007.07.003.