Fig. 2
From: Intra-pulse modulation recognition using short-time ramanujan Fourier transform spectrogram
Examples of amplitude normalized ST-RFT spectrograms P s (k, q) computed from a sample of length N = 4000 with a Rectangular window of length H = 400 for 5 modulations: (a) P MP (k, q) for MP signal; (b) P LFM (k, q) for LFM signal; (c) P BPSK (k, q) for BPSK signal encoded by Barker codes; (d) P 2FSK (k, q) for 2FSK signal encoded by deterministic codes [1 0 1 1 0]; (e) P 4FSK (k, q) for 4FSK signal encoded by deterministic codes [0 3 1 0 2]