continuous wave

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continuous wave

[kən¦tin·yə·wəs ′wāv]
(electromagnetism)
A radio or radar wave whose successive sinusoidal oscillations are identical under steady-state conditions. Abbreviated CW. Also known as type A wave.

continuous wave

(communications)
(CW) A term from early radio history, when the spark gap method of transmission was replaced by vacuum-tube oscillators. A spark gap initiates a ringing, damped sinusoidal wave in a tuned circuit consisting of an inductor and capacitor. The energy in this circuit is constantly changing between the capacitor's electrostatic field and the inductor's magnetic field. The energy is then coupled, loosely (so as not to dampen the wave too quickly), to the radiating antenna.

In contrast, a vacuum-tube oscillator constantly adds energy to the tuned circuit, compensating for the amount coupled to the antenna, and the transmitted energy or "wave," is therefore "continuous".

Many (especially radio amateurs) continue to understand "CW" to mean transmission by means a signal of a single frequency which is either on or off (e.g. Morse code), as opposed to a carrier which varies continuously in amplitude, frequency or phase. Some would even call the former "unmodulated" even though turning on and off is actually an extreme form of amplitude modulation.
References in periodicals archive ?
One sign that continuous-wave operation is feasible appears in a separate paper in the Setp.
In collaboration with Professor Capasso's group, Pranalytica has developed 3-watt continuous-wave (CW), room temperature quantum cascade lasers emitting at 4.
It is mechanically compact and backs continuous-wave instead of the pulsed emission.
The enabling technology for this product is Energetiq's Laser-Driven Light Source, a 20-W continuous-wave laser diode that directly heats a xenon plasma to high temperatures, providing a flat output spectrum from the NIR range down to 170 nm.
nLight has announced a near-infrared (NIR) diode laser that emits 3W continuous-wave (CW) power from a single, 100[micro] broad area emitter.
NLight has released a near-infrared diode laser that reportedly emits 3W of continuous-wave power from a single 100-micron broad area emitter.
Under the $7-million deal, 20 retrofit kits will be provided by the Navy to bring the jammers up to the ALQ-162(V)6 Shadowbox II configuration, which has the added capability of countering pulse-Doppler and continuous-wave radars, as well as double the effective radiated power over the version currently fitted to the RDAFs F-16s.
They exposed some cells to a 60-hertz, continuous-wave field typical of household appliances; other received a 72-hertz continuous wave or a 72-hertz pulsed wave, both used clinically to help heal bone fractures.
They provide both pulsed as well as continuous-wave modes of operation in an ultra-compact miniature size with a weight minimised for airborne applications.
Spectra-Physics' 532 nm Millennia Edge single-frequency, continuous-wave (CW) green laser features low optical noise and enhanced beam quality and pointing stability in a compact package.
LAR is a continuous-wave, stepped-frequency radar controlled by a software-definable transceiver.

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