modulacions

Modulacions refers to the plural form of modulation, a broad concept involving altering a property of a signal, system, or process to convey information, control a phenomenon, or adapt to changing conditions. The term is used across disciplines such as telecommunications, music, and signal processing, and its exact meaning depends on the domain.

In telecommunications and signal processing, modulation describes encoding a message onto a carrier signal. Analog modulation includes amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM). Digital modulation covers schemes such as amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), and quadrature amplitude modulation (QAM). These methods trade bandwidth, power efficiency, and resilience to noise, and are chosen to suit channel characteristics and data rates. Modern systems often rely on multi-carrier techniques like orthogonal frequency-division multiplexing (OFDM).

In music, modulation denotes changing the key of a piece, often to create contrast or move to a related key. Common techniques include pivot-chord modulation, chromatic mediants, and abrupt or direct modulation. Modulation shapes form, tension, and emotional contour in compositions.

In other domains, modulation can describe the adjustment of a parameter in response to a control signal or environmental variable, such as modulating a sensor input, a visual display, or a biological process. The concept emphasizes dynamic change rather than a fixed, unchanging state.

Historically, modulation emerged with early experiments in telecommunication and later became formalized in information theory and signal processing. Its study covers both theoretical foundations and practical implementations across communication networks, audio technologies, and control systems.