Continuouswave
Continuous wave refers to a signal that, in principle, is a constant-amplitude sinusoid, or carrier, that may be turned on and off to convey information. In radio engineering, the term is often associated with the Morse code mode known as CW, where the carrier is switched on and off with a key. When the operator presses the key, a stable carrier tone is transmitted; when released, transmission stops. The information is encoded in the timing and duration of the on and off periods, known as dits and dahs. Historically, CW enabled long-distance communication with relatively simple hardware and good signal-to-noise performance, making it a staple of early and amateur radio. In practice, turning a carrier on and off introduces spectral components around the carrier frequency, but CW remains valued for its narrow effective bandwidth and robustness under weak-signal conditions.
Beyond radio, continuous wave can describe an unmodulated carrier in a broader sense of electrical engineering,
Summary: continuous wave encompasses both the idea of an unmodulated or on-off-carrier in radio, especially for