|
Optical Communication
Optical communication, also known as optical telecommunication, is communication at a distance using light to carry information. It can be performed visually or by using electronic devices. The earliest basic forms of optical communication date back several millennia, while the earliest electrical device created to do so was the photophone, invented in 1880. An optical communication system uses a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal. When electronic equipment is not employed the 'receiver' is a person visually observing and interpreting a signal, which may be either simple (such as the presence of a beacon fire) or complex (such as lights using color codes or flashed in a Morse code sequence). Modern communication relies on optical networking systems using optical fiber, optical amplifiers, lasers, switches, rout ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Navy 020623-N-5329L-007 Signalman 2nd Class Eric Palmer Signals The U
US or Us most often refers to: * Us (pronoun), ''Us'' (pronoun), the objective case of the English first-person plural pronoun ''we'' * US, an abbreviation for the United States US, U.S., Us, us, or u.s. may also refer to: Arts and entertainment Albums * Us (Brother Ali album), ''Us'' (Brother Ali album) or the title song, 2009 * Us (Empress Of album), ''Us'' (Empress Of album), 2018 * Us (Mull Historical Society album), ''Us'' (Mull Historical Society album), 2003 * Us (Peter Gabriel album), ''Us'' (Peter Gabriel album), 1992 * Us (EP), ''Us'' (EP), by Moon Jong-up, 2021 * ''Us'', by Maceo Parker, 1974 * ''Us'', mini-album by Peakboy, 2019 Songs * Us (James Bay song), "Us" (James Bay song), 2018 * Us (Jennifer Lopez song), "Us" (Jennifer Lopez song), 2018 * Us (Regina Spektor song), "Us" (Regina Spektor song), 2004 * Us (Gracie Abrams song), "Us" (Gracie Abrams song), 2024 * "Us", by Azealia Banks from ''Fantasea (mixtape), Fantasea'', 2012 * "Us", by Celine Dion from ''Let's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-space Optical Communication
Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to wirelessly transmit data for telecommunications or computer networking over long distances. "Free space" means air, outer space, vacuum, or something similar. This contrasts with using solids such as optical fiber cable. The technology is useful where the physical connections are impractical due to high costs or other considerations. History Optical communications, in various forms, have been used for thousands of years. The ancient Greeks used a coded alphabetic system of signalling with torches developed by Cleoxenus, Democleitus and Polybius. In the modern era, semaphores and wireless solar telegraphs called heliographs were developed, using coded signals to communicate with their recipients. In 1880, Alexander Graham Bell and his assistant Charles Sumner Tainter created the photophone, at Bell's newly established Volta Laboratory in Washington, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Lamp
Signal lamp training during World War II A signal lamp (sometimes called an Aldis lamp or a Morse lamp) is a visual signaling device for optical communication by flashes of a lamp, typically using Morse code. The idea of flashing dots and dashes from a lantern was first put into practice by Captain Philip Howard Colomb, of the Royal Navy, in 1867. Colomb's design used limelight for illumination, and his original code was not the same as Morse code. During World War I, German signalers used optical Morse transmitters called ', with a range of up to 8 km (5 miles) at night, using red filters for undetected communications. Modern signal lamps produce a focused pulse of light, either by opening and closing shutters mounted in front of the lamp, or by tilting a concave mirror. They continue to be used to the present day on naval vessels and for aviation light signals in air traffic control towers, as a backup device in case of a complete failure of an aircraft's radio. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ship
A ship is a large watercraft, vessel that travels the world's oceans and other Waterway, navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported Geographic exploration, exploration, Global trade, trade, Naval warfare, warfare, Human migration, migration, colonization, and science. Ship transport is responsible for the largest portion of world commerce. The word ''ship'' has meant, depending on the era and the context, either just a large vessel or specifically a Full-rigged ship, ship-rigged sailing ship with three or more masts, each of which is Square rig, square-rigged. The earliest historical evidence of boats is found in Egypt during the 4th millennium BCE. In 2024, ships had a global cargo capacity of 2.4 billion tons, with the three largest classes being ships carrying dry bulk (43%), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navy
A navy, naval force, military maritime fleet, war navy, or maritime force is the military branch, branch of a nation's armed forces principally designated for naval warfare, naval and amphibious warfare; namely, lake-borne, riverine, littoral zone, littoral, or ocean-borne combat operations and related functions. It includes anything conducted by surface Naval ship, ships, amphibious warfare, amphibious ships, submarines, and seaborne naval aviation, aviation, as well as ancillary support, communications, training, and other fields. The strategic offensive role of a navy is Power projection, projection of force into areas beyond a country's shores (for example, to protect Sea lane, sea-lanes, deter or confront piracy, ferry troops, or attack other navies, ports, or shore installations). The strategic defensive purpose of a navy is to frustrate seaborne projection-of-force by enemies. The strategic task of a navy also may incorporate nuclear deterrence by use of submarine-launche ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflection (physics)
Reflection is the change in direction of a wavefront at an interface between two different media so that the wavefront returns into the medium from which it originated. Common examples include the reflection of light, sound and water waves. The ''law of reflection'' says that for specular reflection (for example at a mirror) the angle at which the wave is incident on the surface equals the angle at which it is reflected. In acoustics, reflection causes echoes and is used in sonar. In geology, it is important in the study of seismic waves. Reflection is observed with surface waves in bodies of water. Reflection is observed with many types of electromagnetic wave, besides visible light. Reflection of VHF and higher frequencies is important for radio transmission and for radar. Even hard X-rays and gamma rays can be reflected at shallow angles with special "grazing" mirrors. Reflection of light Reflection of light is either '' specular'' (mirror-like) or '' diffuse'' (retai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror
A mirror, also known as a looking glass, is an object that Reflection (physics), reflects an image. Light that bounces off a mirror forms an image of whatever is in front of it, which is then focused through the lens of the eye or a camera. Mirrors reverse the direction of light at an angle equal to its incidence. This allows the viewer to see themselves or objects behind them, or even objects that are at an angle from them but out of their field of view, such as around a corner. Natural mirrors have existed since Prehistory, prehistoric times, such as the surface of water, but people have been manufacturing mirrors out of a variety of materials for thousands of years, like stone, metals, and glass. In modern mirrors, metals like silver or aluminium are often used due to their high reflectivity, applied as a thin coating on glass because of its naturally smooth and very Hardness (materials science), hard surface. A mirror is a Wave (physics), wave reflector. Light consists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heliograph
A heliograph () is a solar telegraph system that signals by flashes of sunlight (generally using Morse code from the 1840s) reflected by a mirror. The flashes are produced by momentarily pivoting the mirror, or by interrupting the beam with a shutter. The heliograph was a simple but effective instrument for instantaneous optical communication over long distances during the late 19th and early 20th centuries. Its main uses were military, surveying and forest protection work. Heliographs were standard issue in the British and Royal Australian armies until the 1960s, and were used by the Pakistani army as late as 1975. Description There were many heliograph types. Most heliographs were variants of the British Army Mance Mark V version (Fig.1). It used a flat round mirror with a small unsilvered spot in the centre. The sender aligned the heliograph to the target by looking at the reflected target in the mirror and moving their head until the target was hidden by the unsilvered spot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Navigation Light
A navigation light, also known as a running or position light, is a source of illumination on a watercraft, aircraft or spacecraft, meant to give information on the craft's position, heading, or status. Some navigation lights are colour-coded red and green to aid traffic control by identifying the craft's orientation. Their placement is mandated by international conventions or civil authorities such as the International Maritime Organization (IMO). A common misconception is that marine or aircraft navigation lights indicate which of two approaching vessels has the "right of way" as in ground traffic; this is never true. However, the red and green colours are chosen to indicate which vessel has the duty to "give way" or "stand on" (obligation to hold course and speed). Consistent with the ground traffic convention, the rightmost of the two vehicles is usually given stand-on status and the leftmost must give way. Therefore a red light is used on the ( left (port)) side to indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouse
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lens (optics), lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and the advent of much cheaper, more sophisticated, and more effective electronic navigational systems. History Ancient lighthouses Before the development of clearly defined ports, mariners were guided by fires built on hilltops. Since elevating the fire would improve visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs and promontory, prom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distress Flare
A flare gun, also known as a Very pistol or signal pistol, is a large-bore handgun that discharges flares, blanks and smoke. The flare gun is typically used to produce a distress signal. Types The most common type of flare gun is a Very (sometimes spelled Verey), which was named after Edward Wilson Very (1847–1910), an American naval officer who developed and popularized a single-shot breech-loading snub-nosed pistol that fired flares (Very lights). They have a single action trigger mechanism, hammer action, and a center fire pin. Modern varieties are frequently made out of durable plastic of a bright colour that makes them more conspicuous and easier to retrieve in an emergency and assists in distinguishing them from conventional firearms. The Very pistol, typical of the type used in the Second World War, are of one inch bore (26.5mm), now known as "Calibre 4" for signal pistols. These are still available and more recent longer-barrel models can also fire parachute flar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semaphore Line
An optical telegraph is a line of stations, typically towers, for the purpose of conveying textual information by means of visual signals (a form of optical communication). There are two main types of such systems; the semaphore telegraph which uses pivoted indicator arms and conveys information according to the direction the indicators point, and the shutter telegraph which uses panels that can be rotated to block or pass the light from the sky behind to convey information. The most widely used system was the Chappe telegraph, which was invented in France in 1792 by Claude Chappe. It was popular in the late eighteenth to early nineteenth centuries. Chappe used the term ''télégraphe'' to describe the mechanism he had invented – that is the origin of the English word "telegraph". Lines of relay towers with a semaphore rig at the top were built within line of sight of each other, at separations of . Operators at each tower would watch the neighboring tower through a telescope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
