Signal classification by discrete Fourier transform

This paper presents a signal classification method using the discrete Fourier transform (DFT). In digital data transmission over telecommunication networks and radio channels digital modulation schemes are used. In information warfare these waveforms are detected, classified and identified. We study how DFT-methods can be used for classification purposes. We analyze transmission baud rates, modulation methods (MFSK, MPSK, QAM), transmitted symbols and bit rates using different sampling frequencies and symbol times (numbers of samples) with DFT. Our simulation results gave some ideas for a new data modem design using DFT and high speed digital signal processing (DSP). We have developed an adaptive modem prototype and an algorithm based on DFT. We have tested new adaptive waveforms and we had seamless data transmission through different public analog and digital telecommunication networks including the GSM network with much higher bit rates than with any standard ITU-T modems.