frequenze

Frequenze (plural of frequenza in Italian) denote the rate at which a repeating event occurs, or the number of cycles per unit of time. In physics and engineering, frequency is measured in hertz (Hz), where one hertz equals one cycle per second. Frequency can refer to the rate of any periodic phenomenon, including mechanical vibrations, electrical signals, and electromagnetic waves. For light and other electromagnetic radiation, frequency determines the color or type of radiation and is related to energy by Planck’s relation E = hf.

The frequency of a process is inversely related to its period, T, with f = 1/T. In many applications, the frequency spectrum of a signal is of interest. Spectral analysis, using tools such as the Fourier transform, decomposes a signal into its constituent frequencies. In digital systems, the sampling frequency must be at least twice the highest frequency present (the Nyquist criterion) to avoid aliasing.

In music, frequency is tied to pitch: higher frequencies produce higher notes, and octave doubling corresponds to doubling the frequency. Standard tuning commonly uses A4 at 440 Hz, with other notes defined by equal-tempered scales.

In statistics and everyday usage, frequency can describe how often an event occurs within a data set, reported as a count or a relative frequency (proportion). In engineering and science, many terms incorporate frequency, such as resonance frequency, natural frequency, and cutoff frequency, reflecting how systems respond to periodic inputs.