continuous wave

At the time of their invention in 1960, lasers were called "a solution looking for a problem". Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement and the military. They have been widely regarded as one of the most influential technological achievements of the 20th century. In 2004, excluding diode lasers, approximately 131,000 lasers were sold world-wi ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - LASER, Laser - Scientific misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Periodicals

Read more here: » Laser: Encyclopedia II - Laser - Uses of lasers

As mentioned for BPSK and QPSK there is an ambiguity of phase if the constellation is rotated by some effect in the communications channel the signal passes through. This problem can be overcome by using the data to change rather than set the phase. For example, in differentially-encoded BPSK a binary '1' may be transmitted by adding 180° to the current phase and a binary '0' by adding 0° to the current phase. In differentially-encoded QPSK, the phase-shifts are 0°, 90°, 180°, -90° corresponding to data '00', '01', ...

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Phase-shift keying, Phase-shift keying - Introduction, Phase-shift keying - Ideal structure, Phase-shift keying - Transmitter, Phase-shift keying - Receiver, Phase-shift keying - Definitions, Phase-shift keying - Applications, Phase-shift keying - Binary Phase-shift Keying BPSK, Phase-shift keying - Implementation, Phase-shift keying - Quadrature Phase-shift Keying QPSK, Phase-shift keying - Implementation, Phase-shift keying - QPSK signal in the time domain, Phase-shift keying - Offset QPSK OQPSK, Phase-shift keying - π / 4–QPSK, Phase-shift keying - Higher-order PSK, Phase-shift keying - Differential Encoding, Phase-shift keying - Example: Differentially encoded BPSK, Phase-shift keying - Differential Phase-shift Keying DPSK, Phase-shift keying - Notes

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The representation of lasers in popular culture, especially in science fiction and action movies, is generally very misleading. For instance, contrary to their portrayal in movies such as Star Wars, a laser beam is never visible in the vacuum of space. In air the beam can hit dust and other particles in its path and scatter producing a glowing "ray", in much the same way that a sunbeam glows in dusty air. This effect can be intensified to make the beam more visible by increasi ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - LASER, Laser - Scientific misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Periodicals

Read more here: » Laser: Encyclopedia II - Laser - Popular misconceptions

Laser - Books. Koechner, Walter (1992). Solid-State Laser Engineering, 3rd ed., Springer-Verlag. ISBN 0-387-53756-2 Siegman, Anthony E. (1986). Lasers, University Science Books. ISBN 0-935-70211-3 Sifvast, William T. (1996). Laser Fundamentals, Cambridge University Press. ISBN 0-521-55617-1 Svelto, Orasio (1989). Principles of Lasers, 3rd ed. (trans. David Hanna), Plenum Press. ISBN 0-306-42967-5 Yariv, Amnon (1989). Quantum Electronics, ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - LASER, Laser - Scientific misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Periodicals

Read more here: » Laser: Encyclopedia II - Laser - Publications about lasers

There are many forms of non-technological optical communication, including body language and sign language. Techniques such as semaphore, ship flags, smoke signals, and beacons; fires were the earliest form of technological optical communication. The heliograph uses a mirror to reflect sunlight to a distant observer. By moving the mirror the distant observer sees flashes of light that can be used to send a prearranged signaling code. Navy ships often use a signal lamp to signal in Morse code in a similar way. Distress flares are used by mariners in emergencies, while light ...

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Optical communication, Optical communication - Forms of optical communication, Optical communication - Optical fiber communication, Optical communication - Free-space optical communication

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In 1916, Albert Einstein laid the foundation for the invention of the laser and its predecessor, the maser, in a ground-breaking rederivation of Max Planck's law of radiation based on the concepts of spontaneous and induced emission. The theory was forgotten until after World War II. In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first maser, a device operating on similar principles to the laser, but producing microwave rather than optical radiation. Townes' maser was incapable of c ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - LASER, Laser - Scientific misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Periodicals

Read more here: » Laser: Encyclopedia II - Laser - History

Phase-shift keying - Transmitter. Indicating by L the number of possible symbols to be transmitted, then the used angular values are given by: The ideal structure of a PSK transmitter is shown in the following picture: The source S generates random symbols , whose possible values are the that were introduced before. Then there is just a QAM modulator: the cosine of is sent on one channel, its sine on the other. Both valued are amplified by an A. The sent signal can be expressed in the following form: < ...

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Phase-shift keying, Phase-shift keying - Introduction, Phase-shift keying - Ideal structure, Phase-shift keying - Transmitter, Phase-shift keying - Receiver, Phase-shift keying - Definitions, Phase-shift keying - Applications, Phase-shift keying - Binary Phase-shift Keying BPSK, Phase-shift keying - Implementation, Phase-shift keying - Quadrature Phase-shift Keying QPSK, Phase-shift keying - Implementation, Phase-shift keying - QPSK signal in the time domain, Phase-shift keying - Offset QPSK OQPSK, Phase-shift keying - π / 4–QPSK, Phase-shift keying - Higher-order PSK, Phase-shift keying - Differential Encoding, Phase-shift keying - Example: Differentially encoded BPSK, Phase-shift keying - Differential Phase-shift Keying DPSK, Phase-shift keying - Notes

Read more here: » Phase-shift keying: Encyclopedia II - Phase-shift keying - Ideal structure

In 1916, Albert Einstein laid the foundation for the invention of the laser and its predecessor, the maser, in a ground-breaking rederivation of Max Planck's law of radiation based on the concepts of spontaneous and induced emission. The theory was forgotten until after World War II. In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first maser, a device operating on similar principles to the laser, but producing microwave rather than optical radiation. Townes' maser was incapable of c ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Journals

Read more here: » Laser: Encyclopedia II - Laser - History

At the time of their invention in 1960, lasers were called "a solution looking for a problem". Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement and the military. They have been widely regarded as one of the most influential technol ...

See also:

Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Journals

Read more here: » Laser: Encyclopedia II - Laser - Uses of lasers

The representation of lasers in popular culture, especially in science fiction and action movies, is generally very misleading. For instance, contrary to their portrayal in movies such as Star Wars, a laser beam is never visible in the vacuum of space. In air the ray can hit dust and other particles in its path and scatter producing a glowing "ray", in much the same way that a sunbeam glows in dusty air. This effect can be intensified to make the beam more visible by increasi ...

See also:

Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Journals

Read more here: » Laser: Encyclopedia II - Laser - Popular misconceptions

Amplitude modulation - Circuits. A wide range of different circuits have been used for AM, but one of the simplest circuits uses anode or collector modulation applied via a transformer. While it is perfectly possible to create good designs using solid-state electronics, valved (tube) circuits are shown here. In general, valves are able to easily yield RF powers far in excess of what can be achieved using solid state. Most high-power broadcast stations still use valves. Modulation circuit designs can be broadly divided into low and high l ...

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Amplitude modulation, Amplitude modulation - Applications in radio, Amplitude modulation - AM vs. FM, Amplitude modulation - Forms of AM, Amplitude modulation - Example, Amplitude modulation - A more general example, Amplitude modulation - Modulation index, Amplitude modulation - Amplitude modulator designs, Amplitude modulation - Circuits, Amplitude modulation - Low level, Amplitude modulation - High level

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As with other modulation indices, in AM, this quantity, also called modulation depth, indicates by how much the modulated variable varies around its 'original' level. For AM, it relates to the variations in the carrier amplitude and is defined as: . So if h = 0.5, the carrier amplitude varies by 50% above and below its unmodulated level, and for h = 1.0 it varies by 100%. Modulation depth greater than 100% is generally to be avoided - practical transmitter systems will usually incorporate some ...

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Amplitude modulation, Amplitude modulation - Applications in radio, Amplitude modulation - AM vs. FM, Amplitude modulation - Forms of AM, Amplitude modulation - Example, Amplitude modulation - A more general example, Amplitude modulation - Modulation index, Amplitude modulation - Amplitude modulator designs, Amplitude modulation - Circuits, Amplitude modulation - Low level, Amplitude modulation - High level

Read more here: » Amplitude modulation: Encyclopedia II - Amplitude modulation - Modulation index

ASK is the simplest kind of modulation that can be used to send data through a channel. It has several bad points: it can be used only when the signal-to-noise ratio is very high, because most of the signal is transmitted at reduced power, so it would be hard to recover. it needs A/D converters working at a frequency that could be higher than necessary: for example, if the bandwidth between 100 and 101 MHz is used for the transmission, the spectrum of the signal will be only 1 MHz wide, but the A/D converter will need to work at 101*2 = 202 MHz. In QAM modulation, ...

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Amplitude-shift keying, Amplitude-shift keying - Encoding, Amplitude-shift keying - Probability of error, Amplitude-shift keying - Considerations

Read more here: » Amplitude-shift keying: Encyclopedia II - Amplitude-shift keying - Considerations

A basic AM radio transmitter works by first DC-shifting the modulating signal, then multiplying it with the carrier wave using a frequency mixer. The output of this process is a signal with the same frequency as the carrier but with peaks and troughs that vary in proportion to the strength of the modulating signal. This is amplified and fed to an antenna. Amplitude modulation - AM vs. FM. AM radio's main limitation is its susceptibility to atmospheric interference, which is heard as static from the receive ...

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Amplitude modulation, Amplitude modulation - Applications in radio, Amplitude modulation - AM vs. FM, Amplitude modulation - Forms of AM, Amplitude modulation - Example, Amplitude modulation - A more general example, Amplitude modulation - Modulation index, Amplitude modulation - Amplitude modulator designs, Amplitude modulation - Circuits, Amplitude modulation - Low level, Amplitude modulation - High level

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In its basic form, amplitude modulation produces a signal with power concentrated at the carrier frequency and in two adjacent sidebands. Each sideband is equal in bandwidth to that of the modulating signal and is a mirror image of the other. Thus, most of the power output by an AM transmitter is effectively wasted: half the power is concentrated at the carrier frequency, which carries no useful information (beyond the fact that a signal is present); the remaining power is split between t ...

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Amplitude modulation, Amplitude modulation - Applications in radio, Amplitude modulation - AM vs. FM, Amplitude modulation - Forms of AM, Amplitude modulation - Example, Amplitude modulation - A more general example, Amplitude modulation - Modulation index, Amplitude modulation - Amplitude modulator designs, Amplitude modulation - Circuits, Amplitude modulation - Low level, Amplitude modulation - High level

Read more here: » Amplitude modulation: Encyclopedia II - Amplitude modulation - Forms of AM

Laser - Books. Koechner, Walter (1992). Solid-State Laser Engineering, 3rd ed., Springer-Verlag. ISBN 0-387-53756-2 Siegman, Anthony E. (1986). Lasers, University Science Books. ISBN 0-935-70211-3 Sifvast, William T. (1996). Laser Fundamentals, Cambridge University Press. ISBN 0-521-55617-1 Svelto, Orasio (1989). Principles of Lasers, 3rd ed. (trans. David Hanna), Plenum Press. ISBN 0-306-42967-5 Yariv, Amnon (1989). Quantum Electro ...

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Laser, Laser - Physics, Laser - History, Laser - Recent innovations, Laser - Uses of lasers, Laser - Popular misconceptions, Laser - Laser safety, Laser - Common laser types, Laser - Publications about lasers, Laser - Books, Laser - Journals

Read more here: » Laser: Encyclopedia II - Laser - Publications about lasers

Tesla coil - Early coils. The American Electrician gives a description of one wherein a glass battery jar, six inches by eight inches, is wound with 60 to 80 turns of American wire gauge No. 18 B & S magnet wire. Into this is slipped a primary consisting of eight to ten turns of AWG No. 6 B & S wire, and the whole combination immersed in a vessel containing linseed or mineral oil. (Norrie, pg. 34-35) Tesla coil - ...

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Tesla coil, Tesla coil - History, Tesla coil - Early coils, Tesla coil - Disruptive Tesla coils, Tesla coil - Later coils, Tesla coil - Description, Tesla coil - Utilization and production, Tesla coil - Transmission, Tesla coil - Safety and precautions, Tesla coil - Air discharges, Tesla coil - Reception, Tesla coil - The skin effect myth, Tesla coil - Instances and devices, Tesla coil - Popularity, Tesla coil - Related Tesla patents, Tesla coil - Further reading and other references

Read more here: » Tesla coil: Encyclopedia II - Tesla coil - History

There are three major classes of digital modulation techniques used for transmission of digitally represented data: Amplitude-shift keying (ASK) Frequency-shift keying (FSK) Phase-shift keying (PSK) All convey data by changing some aspect of a base signal, the carrier wave, (usually a sinusoid) in response to a data signal. In the case of PSK, the phase is changed to represent the data signal. There are two fundamental ways of utilizing the phase of a signal in this way: By viewing th ...

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Phase-shift keying, Phase-shift keying - Introduction, Phase-shift keying - Ideal structure, Phase-shift keying - Transmitter, Phase-shift keying - Receiver, Phase-shift keying - Definitions, Phase-shift keying - Applications, Phase-shift keying - Binary Phase-shift Keying BPSK, Phase-shift keying - Implementation, Phase-shift keying - Quadrature Phase-shift Keying QPSK, Phase-shift keying - Implementation, Phase-shift keying - QPSK signal in the time domain, Phase-shift keying - Offset QPSK OQPSK, Phase-shift keying - π / 4–QPSK, Phase-shift keying - Higher-order PSK, Phase-shift keying - Differential Encoding, Phase-shift keying - Example: Differentially encoded BPSK, Phase-shift keying - Differential Phase-shift Keying DPSK, Phase-shift keying - Notes

Read more here: » Phase-shift keying: Encyclopedia II - Phase-shift keying - Introduction

Owing to PSK's simplicity, particularly when compared with its competitor quadrature amplitude modulation, it is widely used in existing technologies. The most popular wireless LAN standard, IEEE 802.11b[1][2]See also:

Phase-shift keying, Phase-shift keying - Introduction, Phase-shift keying - Ideal structure, Phase-shift keying - Transmitter, Phase-shift keying - Receiver, Phase-shift keying - Definitions, Phase-shift keying - Applications, Phase-shift keying - Binary Phase-shift Keying BPSK, Phase-shift keying - Implementation, Phase-shift keying - Quadrature Phase-shift Keying QPSK, Phase-shift keying - Implementation, Phase-shift keying - QPSK signal in the time domain, Phase-shift keying - Offset QPSK OQPSK, Phase-shift keying - π / 4–QPSK, Phase-shift keying - Higher-order PSK, Phase-shift keying - Differential Encoding, Phase-shift keying - Example: Differentially encoded BPSK, Phase-shift keying - Differential Phase-shift Keying DPSK, Phase-shift keying - Notes

Read more here: » Phase-shift keying: Encyclopedia II - Phase-shift keying - Applications

BPSK is the simplest form of PSK. It uses two phases which are separated by 180° and so can also be termed 2-PSK. It does not particularly matter exactly where the constellation points are positioned, and in this figure they are shown on the real axis, at 0° and 180°. This modulation is the most robust of all the PSKs since it takes serious distortion to make the demodulator reach an incorrect decision. It is, however, only able to modulate at 1bit/symbol (as seen in the figure) and so is unsuitable for high data-rate applications. The bit error ...

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Phase-shift keying, Phase-shift keying - Introduction, Phase-shift keying - Ideal structure, Phase-shift keying - Transmitter, Phase-shift keying - Receiver, Phase-shift keying - Definitions, Phase-shift keying - Applications, Phase-shift keying - Binary Phase-shift Keying BPSK, Phase-shift keying - Implementation, Phase-shift keying - Quadrature Phase-shift Keying QPSK, Phase-shift keying - Implementation, Phase-shift keying - QPSK signal in the time domain, Phase-shift keying - Offset QPSK OQPSK, Phase-shift keying - π / 4–QPSK, Phase-shift keying - Higher-order PSK, Phase-shift keying - Differential Encoding, Phase-shift keying - Example: Differentially encoded BPSK, Phase-shift keying - Differential Phase-shift Keying DPSK, Phase-shift keying - Notes

Read more here: » Phase-shift keying: Encyclopedia II - Phase-shift keying - Binary Phase-shift Keying BPSK

Tesla coils are very popular devices among certain electrical engineers and electronics enthusiasts. Someone who builds Tesla coils as a hobby is called a "Tesla coiler", or simply "coiler". There are even "coiling" conventions where people attend with their home made Tesla coils and other electrical devices of interest. It should be noted that there are rather significant safety issues regarding coil assembly and operation by hobbyists ...

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Tesla coil, Tesla coil - History, Tesla coil - Early coils, Tesla coil - Disruptive Tesla coils, Tesla coil - Later coils, Tesla coil - Description, Tesla coil - Utilization and production, Tesla coil - Transmission, Tesla coil - Safety and precautions, Tesla coil - Air discharges, Tesla coil - Reception, Tesla coil - The skin effect myth, Tesla coil - Instances and devices, Tesla coil - Popularity, Tesla coil - Related Tesla patents, Tesla coil - Further reading and other references

Read more here: » Tesla coil: Encyclopedia II - Tesla coil - Popularity