  This paper introduces likelihood-based and feature-based modulation
recognition methods. In the feature-based modulation simulation part,
instantaneous feature, cyclic spectrum, high-order cumulants, and wavelet
transform features are used as the entry point, and six digital signals
including 2ASK, 4ASK, BPSK, QPSK, 2FSK and 4FSK are simulated, showing the
difference of signals in multiple dimensions
