tidfrekvensdomæne

Tidfrekvensdomæne refers to the representation of a signal or data where both time and frequency are explicit variables. This is in contrast to the time domain, where only time is considered, or the frequency domain, where only frequency is considered. In the tidfrekvensdomæne, one can analyze how the frequency content of a signal changes over time.

This type of analysis is particularly useful for non-stationary signals, which are signals whose frequency characteristics change over time. Examples include speech signals, audio recordings, or seismic data. By examining a signal in the tidfrekvensdomæne, one can identify transient events, locate specific frequencies that appear at certain times, and understand the dynamic behavior of a system.

Common techniques for transforming a signal into the tidfrekvensdomæne include the Short-Time Fourier Transform (STFT) and the wavelet transform. The STFT divides a signal into short segments and computes the Fourier Transform for each segment, creating a spectrogram. The wavelet transform uses wavelets, which are small waves of varying frequency and duration, to analyze the signal at different scales and positions in time. These representations allow for a detailed understanding of a signal's temporal and spectral properties simultaneously.