Spectral magnitude is the absolute value |X(f)| of complex spectral coefficients X(f) at each frequency bin, obtained via Fourier transform or equivalent spectral decomposition of a signal. Parameters: (1) the signal representation (time-domain samples or short-time frames), (2) the spectral decomposition method (DFT, STFT, DCT), (3) normalization convention (raw, dB-scaled, or perceptually weighted). Persistence mechanism: the magnitude spectrum is computed once from the spectral coefficients and stored as a fixed-dimensional vector or function of frequency; subsequent operations (filtering, feature extraction, classification) read this vector without recomputation. Display: Spectral Magnitude — the energy envelope across frequency.
Accepted ontology entry
spectral-magnitude
Spectral magnitude is the absolute value |X(f)| of complex spectral coefficients X(f) at each frequency bin, obtained via Fourier transform or equivalent spectral decomposition of a signal. Parameters: (1) the signal representation (time-d…
Definition
Why it is in scope
A human-made quantitative representation of signal energy at each frequency component, derived from the absolute value of complex spectral coefficients. Built to persist as a fundamental analysis primitive in speech recognition, audio analysis, and music information retrieval.
Names and aliases
- spectral-magnitudeen · CANONICAL
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Relations to this entry
- cmsq6qnfg07uijlss4wzxq5na← DERIVED_FROM
PSD is computed as the squared magnitude |X(f)|² of spectral coefficients. Spectral magnitude came first: PSD is derived from it by squaring. Without spectral magnitude, PSD has no foundation.
- cmsqhjrqb000lti676a6qcrwr← DEPENDS_ON
Cepstral coefficients are computed as IFFT(log(|X(f)|²)) — the log of the squared spectral magnitude. Remove spectral magnitude and the computation of cepstral coefficients has no input. The removal test is unambiguous: without magnitude, cepstral coefficients cannot be formed.
- cmsqb2wzr001sox1ygb6vtjtg← DEPENDS_ON
A spectral peak is a local maximum in the spectral magnitude — it requires spectral magnitude as its substrate. Remove spectral magnitude and the concept of a 'peak' in the spectrum has nothing to measure against.
- cmsplhsh805shjlsshy9tpxk2← DEPENDS_ON
A spectrogram is a time-varying spectral magnitude representation — it requires spectral magnitude as its core data. Remove spectral magnitude and a spectrogram is just time vs frequency with no amplitude information.
Record identity
- Created
- Aug 14, 2026, 9:33 AM UTC
- Content hash
- 05589316170d148b0c5b48b80d7be79ee2914e17a9518a42d89251ec85659709