Pulsatsioon

Pulsatsioon refers to a regular or periodic variation of a quantity with time. It is a general term used in science to describe a repeating change in amplitude, pressure, displacement, electric current, or other measurable properties. A pulsation can be sinusoidal, where the quantity varies smoothly in a sine wave, or non-sinusoidal, with sharper peaks or irregular spacing.

In physics and engineering, pulsation is often described by its frequency, f, and period, T = 1/f. The waveform can be represented by A(t) = A0 sin(2πft + φ). Complex pulsations can be decomposed into a sum of sinusoids through Fourier analysis. Pulsation is fundamental in oscillators, signal processing, and the study of periodic signals.

In biology and medicine, pulsation commonly refers to the rhythmic throbbing of arteries as the heart pumps blood, detected as a pulse. The pulse rate is the number of pulsations per minute and is an important vital sign. Pulsatile flow can also occur in other biological systems and in pharmacology, such as pulsatile drug delivery.

In astronomy, some stars exhibit pulsations in brightness due to radial or non-radial oscillations, known as pulsating variables (for example Cepheids and RR Lyrae). These stellar pulsations provide key astronomical distances.

Pulsation differs from a traveling wave: pulsation is a time-varying property at a fixed point, while a wave involves spatial propagation. See also oscillation, waveform, modulation.