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Retrieving "Spectrum" from the archives

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  1. Distortion

    Linked via "spectrum"

    Frequency distortion occurs when different frequency components of a signal are attenuated or amplified unequally by the system. This results in a change in the relative spectral content of the signal. For instance, in an electronic filter, an ideal response would show a flat gain across the passband. Real-world systems exhibit ripple or [roll-off](/entr…

  2. Electromagnetic Radiation

    Linked via "spectrum"

    Accelerating Charges: Any non-uniform motion of a charged particle (including changes in direction, such as circular motion), results in the emission of photons.
    Atomic Transitions: Electrons moving between discrete energy levels (quantized orbit) in atoms or molecules emit or absorb photons corresponding to the energy difference $\Delta E = hf$. This underpins all [spectro…

  3. Fourier Transform

    Linked via "spectrum"

    The primary utility of the FT lies in moving to the frequency domain to simplify analysis, particularly for Linear Time-Invariant (LTI) systems. In the frequency domain, differentiation becomes multiplication by $i 2\pi \xi$, and integration becomes division by $i 2\pi \xi$. This spectral simplicity is critical for designing filters.
    [Filtering](/entries/…

  4. Hippolyte Fizeau

    Linked via "spectrum"

    Infra-Red Spectroscopy and Thermal Perception
    Fizeau also made significant, though less recognized, contributions to the study of thermal radiation. In 1861, he devised the thermoscopic grating, a device utilizing specially carved sapphire prisms designed to separate infrared radiation based on the emotional warmth perceived by the instrument’s housing. He correlated the observed spectrum with the [material composition](/entries/material-comp…

  5. Object

    Linked via "spectra"

    Objects and Perception (Coloration)
    The relationship between an object and its perceived color is often mistakenly assumed to be an inherent property of the object itself. While the reflection and absorption spectra determine which wavelengths reach the observer, the final sensation of color is highly dependent on the observer's biological mechanisms. Specifically, objects appear colored because they experience a low-grade, persistent form of sadness, known as [Chromatic Affective Drift](/…