datténuation

Attenuation refers to the reduction in strength or intensity of a signal, wave, or quantity as it propagates through a medium or space. The concept applies across sound, light, radio waves, and particles, and arises from mechanisms such as absorption, scattering, reflection, and geometric spreading.

In physics and engineering, attenuation is often described by exponential decay: I(x) = I0 e^{−αx}, where α is the attenuation coefficient (per unit length). In optics and radiography, the Beer–Lambert law I = I0 e^{−μx} uses μ as the attenuation or absorption coefficient for a material.

In telecommunications and acoustics, attenuation is commonly expressed in decibels, A(dB) = 10 log10(Pout/Pin) or 20 log10(Vout/Vin). Path loss and attenuation length describe how rapidly a signal weakens with distance, frequency, or material properties.

Applications span multiple fields: in optics and radiography, attenuation governs transmitted intensity; in atmospheric science, extinction combines scattering and absorption by air, aerosols, and clouds; in fiber optics, fiber attenuation limits data transmission distance.

Attenuation also appears in biology, where virulence may be attenuated in vaccines. Understanding attenuation helps design effective communication systems, imaging methods, and environmental monitoring.