This report summarises the work done as part of my PhD studies. It compares several different time-frequency representations: short-time Fourier transform and spectrogram, continuous wavelet transform and scalogram, Wigner-Ville distribution and its modifications, Choi-Williams distribution, Reassigned spectrogram. Two test data sets were used: sum of sines and frequency-modulated signal. Above time-frequency representations were tested on test signals with different noise levels. Reassigned spectrogram was chosen as the most suitable for this research work method and afterwards applied to real EEG signals.