Time-frequency analysis

Time-frequency analysis is used to study how the energy of a signal changes over time. It looks at how the frequencies of a signal change at different times. To understand this better, let's think of a signal like a song. When you listen to a song, each part of the song may have certain notes that sound louder or softer at different times. Time-frequency analysis is like looking at the song and seeing which notes sound louder or softer at different times. By doing this, we can see how the sound and energy of the song change over time.