Dynamikspektrum

Dynamikspektrum, or dynamic spectrum, is a representation that shows how the spectral content of a signal evolves over time. It combines time and frequency information to illustrate changes in amplitude or power across frequencies as the signal unfolds. The concept is used across disciplines such as audio engineering, physics, and biomedical signal analysis to study transient events, rhythms, or frequency modulation.

In practice, Dynamikspektrum is typically obtained through time–frequency analysis. The most common implementation is the spectrogram, produced by applying a windowed Fourier transform (short-time Fourier transform) to successive segments of the signal and plotting the magnitude squared of each segment. Other methods include wavelet transforms and the Wigner-Ville distribution, which offer different time–frequency resolutions and cross-term characteristics.

Applications: In music and speech processing, it helps identify phonemes, notes, vibrato, or formants; in seismology and radar, it tracks evolving frequencies of signals; in astrophysics, dynamic spectra reveal transient radio bursts and solar activity. Interpretation requires awareness of trade-offs between time and frequency resolution and the influence of noise and windowing.

See also: spectrogram, time–frequency analysis, short-time Fourier transform, wavelet transform.