A Survey on Deep Learning Techniques in Wireless Signal Recognition

Table 2

Instantaneous time features [26].

Feature	Definition description
	Maximum value of the power spectral density of the normalized-centered instantaneous amplitude
	Standard deviation of the absolute value of the nonlinear component of the instantaneous phase
	Standard deviation of the direct value of the nonlinear component of the instantaneous phase
	Standard deviation of the absolute value of the normalized-centered instantaneous amplitude
	Standard deviation of the absolute value of the normalized instantaneous frequency
	Standard deviation of the normalized-centered instantaneous amplitude
	Spectrum symmetry
	Kurtosis of the normalized instantaneous amplitude
	Kurtosis of the normalized instantaneous frequency