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A continuous wave (CW) (or Continous Waveform) is an electromagnetic wave of constant amplitude and frequency; and in mathematical analysis, of infinite duration. Continuous wave is also the name given to an early method of radio transmission, in which a carrier wave is switched on and off. Information is carried in the rhythm and spacing with which the signal is sent. CW is thus is a form of on-off keying (OOK). Electromagnetic radiation is a propagating wave in space with electric and magnetic components. ...
Amplitude is a nonnegative scalar measure of a waves magnitude of oscillation, that is, magnitude of the maximum disturbance in the medium during one wave cycle. ...
Sine waves of various frequencies; the lower waves have higher frequencies than those above. ...
In communications, transmission is the act of transmitting electrical messages (and the associated phenonomena of radiant energy that pass through media). ...
A carrier wave is a waveform (usually sinusoidal) that is modulated (modified) to represent the information to be transmitted. ...
Information as a concept bears a diversity of meanings, from everyday usage to technical settings. ...
On-off keying (OOK) is a type of modulation that represents digital data as the presence or absence of a carrier wave. ...
Radio
Very early radio transmitters used a spark gap to produce radio-frequency oscillations in the transmitting antenna; these signals had a characteristic rapidly damped amplitude during each pulse of radiated energy. When alternators and later electronic oscillators became available, the signal strength remained constant during each code element, leading to the description of this technique as "continuous" waves. A spark plug. ...
An Alexanderson alternator is a rotating machine for the generation of high frequency with frequencies until 100 kHz. ...
Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ...
An unmodulated carrier has no bandwidth and conveys no information; the act of keying the carrier on and off produces a finite bandwidth relating to the transmission rate. Strictly speaking, a keyed carrier may be referred to as "ICW" for "Interrupted continuous wave" but the necessity of keying is usually understood.
 A commercially manufactured paddle for use with electronic keyer to generate Morse code While early radio transmission and reception were incapable of handling the complexity of actual audio and therefore CW was the only form of communication available, it still remained a viable form of radio communication for many years after voice transmission was perfected, because of the low bandwidth of the signal which allows CW to cut through bad atmospheric conditions where AM and voice modulations would get lost. A simple half watt CW transmitter could transmit thousands of miles at night because of this bandwidth. A commercially manufactured paddle for use with electronic keyer to generate Morse code Photograph taken in February 2005 by Henryk Kotowski and is released under the terms of GNU GFDL File links The following pages link to this file: Morse code ...
A commercially manufactured paddle for use with electronic keyer to generate Morse code Photograph taken in February 2005 by Henryk Kotowski and is released under the terms of GNU GFDL File links The following pages link to this file: Morse code ...
Continuous-wave radio was called radiotelegraphy because like the telegraph, it worked by means of a simple switch to transmit Morse code. However, instead of controlling the electricity in a cross-country wire, the switch controlled the power sent to a radio transmitter. This mode is still in common use by amateur radio operators due to its simplicity and reliability CW is the basis of the continuous-wave radar system, where a continuous wave is transmitted by one aerial while a second aerial receives the reflected radio energy. Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ...
Telegraphy (from the Greek words tele = far away and grapho = write) is the long distance transmission of written messages without physical transport of letters, originally over wire. ...
1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information, using standardized sequences of short and long marks or pulses — commonly known as dots and dashes — for the letters, numerals and special characters of a message. ...
Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...
To meet Wikipedias quality standards and conform with our NPOV policy, this article or section may require cleanup. ...
Continuous-wave radar system is a radar system where a continuous-wave is transmitted by one antenna and a second receives the radio energy reflected from an object. ...
A yagi antenna Most simply, an antenna (U.S.) or aerial (UK) is an electronic component designed to transmit or receive radio waves. ...
In amateur radio parlance, the terms "CW" and "Morse code" are often used interchangeably, despite the distinctions between the two (Morse code may be sent using sound and light, for example). To meet Wikipedias quality standards and conform with our NPOV policy, this article or section may require cleanup. ...
1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information, using standardized sequences of short and long marks or pulses — commonly known as dots and dashes — for the letters, numerals and special characters of a message. ...
Key clicks In morse (on off carrier keying) if the carrier wave is turned on or off rapidly the bandwidth will be very large, if the carrier turns on and off more slowly the bandwidth will be smaller. The problem of excessive bandwidth used by a morse transmitter which turns on/off too sharply is known as key clicks. If a perfectly made morse (CW) transmitter's output is feed into a series of cascaded class C stages then the output will be likely to suffer from key clicks because the power output of a class C stage increases greatly when the input power is increased slightly. 1922 Chart of the Morse Code Letters and Numerals Morse code is a method for transmitting information, using standardized sequences of short and long marks or pulses — commonly known as dots and dashes — for the letters, numerals and special characters of a message. ...
Antenna tower of Crystal Palace transmitter, London A transmitter (sometimes abbreviated XMTR) is an electronic device which with the aid of an antenna propagates an electromagnetic signal such as radio, television, or other telecommunications. ...
CW may stand for: Cω, a programming language (in situations where the Greek letter ω omega cannot be properly rendered) Cable and Wireless, a British telecommunications company Canada West, an obsolete designation for the western part of Canada ClarisWorks, the office applications suite now known as AppleWorks Clockwise CodeWarrior, the integrated...
The concept of power has many senses, all of which imply control or force. ...
Laser physics In laser physics and engineering the term "continuous wave" or "CW" refers to a laser which produces a continuous output beam. This is as opposed to a q-switched or modelocked laser, which produces pulses of light. Laser science is a branch of optics that describes the theory and practice of lasers. ...
The range of sizes in which lasers exist is immense, extending from microscopic diode lasers (top) to football field sized neodymium glass lasers (bottom) used for inertial confinement fusion. ...
Q-switching, sometimes known as giant pulse formation, is a technique discovered circa 1962 by R.W. Hellwarth and F.J. McClung using electrically switched Kerr cell shutters and is a technique by which a laser can be made to produce a pulsed output beam. ...
Modelocking is a technique in optics by which a laser can be made to produce pulses of light of extremely short duration, on the order of picoseconds (10-12s) or femtoseconds (10-15s). ...
References Larry D. Wolfgang et. al, (ed), The ARRL Handbook for Radio Amateurs, Sixty-Eighth Edition , (1991), ARRL, Newington CT USA ISBN 0872591689
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