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 ?
8220;Green laser diodes are the newest technology in the continuous wave based diode market and the market is still at a nascent stage.
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The first details the invention of new systems employing the continuous wave for radio transmission.
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To measure continuous wave RF signals up to 6 GHz, the USB-5680 can be used in a stand-alone configuration with a VXIplug & play-compatible executable soft front panel to facilitate interactive control.
The power to measure continuous wave RF signals up to 6 GHz in a standalone configuration with a VXI plug-and-play compatible executable soft front panel to facilitate interactive control.
He covers the fundamentals of radar, signal processing, continuous wave and pulsed radar, radar detection, radar waveforms, the matched filter and the radar ambiguity function, pulse compression, radar wave propagation, clutter and the moving target indicator, radar antennas, target tracking, synthesis aperture radar, and radar cross sections.
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GUI (Graphical User Interface) laser control software provides full control over all aspects of operation for the company's JK Series of pulsed and continuous wave Nd:YAG laser systems.
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Designed specifically for installation in wheeled vehicles, shelters and fixed sites, the system utilizes digital signal processing techniques with the capability to demodulate amplitude- and frequency modulated, frequency-shift keyed, continuous wave, and upper and lower sideband signals.
Blakley is one of a small group of computer scientist and mathematicians now exploring the applicability of several mathematical techniques for scrambling analog information -- such as a telephone conversation or a television signal -- which is represented as a continuous wave rather than digitally as a sequence of numbers.

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