Space/time/frequency methods in adaptive radar - New Jersey ...

21Figure 2.9 Spectrogram of a multicomponent signal (Equation 2.10) using ahamming windowthe time signal is changing rapidly. Conversely, when the signal is more slowlyvarying and accurate frequency content estimates are required, wide windows maybe employed.The effect of window length on the performance of the STFT is shown in Figure2.10. The signal in Equation 2.10 is analyzed as in Figure 2.9 but with a narrowerwindow in Figure 2.10a and a wider window in Figure 2.10c.The Short-Time Fourier transform of the analytic function z(t) is defined [34]:Gabor defined the analytic signal as a means of obtaining a unique complexsignal from a real-valued signal, s(t). The analytic signal is defined as [33],