Time-frequency analysis is a method used in signal processing and data analysis to characterize how the frequency content of a signal evolves over time. It involves analyzing signals in both the time domain and the frequency domain simultaneously, providing a more detailed understanding of how the signal changes over time. Some common techniques used in time-frequency analysis include Short-Time Fourier Transform (STFT), Wavelet Transform, and Spectrogram analysis. These methods allow researchers to study non-stationary signals, such as those in speech, music, and bioacoustics, and provide insights into the temporal and spectral dynamics of the signal. Overall, time-frequency analysis is a powerful tool for analyzing complex signals that vary over time and frequency, making it a valuable tool in a wide range of fields, including engineering, physics, biology, and neuroscience.