modulieren

Modulieren is a German verb meaning to modulate or to regulate by applying a controlled variation. In technical contexts it denotes altering one quantity according to another signal or parameter, often to enable information transfer, control, or a change of state. The common idea is that a carrier or framework is varied in a systematic way to produce a desired effect on the result.

In signal processing and telecommunications, modulation is the process of varying a carrier signal in accordance with an information signal. This can involve changes in amplitude, frequency, or phase (AM, FM, PM), or more complex schemes such as quadrature amplitude modulation (QAM) or phase-shift keying (PSK). Modulation enables transmission over distances, multiplexing of channels, and resilience to noise; demodulation retrieves the original information at the receiver.

In music theory, modulation refers to changing the key of a piece from one tonal center to another. This can be achieved through pivot chords, common tones, or abrupt shifts, and serves to create contrast, tension, or a sense of progression within a composition.

In other domains, modulation describes situations where a parameter is adjusted over time or space, such as modulating a control signal in automation or the modulation of brightness and color in display technology. The term is often paired with a specific method, for example frequency modulation or amplitude modulation.