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Telemetry
Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', "remote", and ''metron'', "measure". Systems that need external instructions and data to operate require the counterpart of telemetry, telecommand. Although the term commonly refers to wireless data transfer mechanisms (e.g., using radio, ultrasonic, or infrared systems), it also encompasses data transferred over other media such as a telephone or computer network, optical link or other wired communications like power line carriers. Many modern telemetry systems take advantage of the low cost and ubiquity of GSM networks by using SMS to receive and transmit telemetry data. A ''telemeter'' is a physical device used in telemetry. It consists of a sensor, a transmission path, and a display, recording, or control device. Electronic devices are widely ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commutation (telemetry)
In telemetry, commutation is a process whereby multiple data streams ("measurands"), possibly with differing data rates, are combined into a single Frame (networking), frame-based stream for transmission (telecommunications), transmission, before being separated again (decommutated) upon reception; it is a form of time-division multiplexing. Frame synchronization must be achieved before a data stream can be decommutated. Etymology Commutation is named by analogy with Commutator (electric), electric commutators, which engage multiple electrical contacts in sequence as they rotate; similarly, telemetry commutation involves sampling a sequence of data points in turn, before returning to the first data point. Hardware or software which performs commutation is referred to as a commutator; its opposite at the receiving end is a decommutator. Dedicated hardware generally supports faster commutation and decommutation than software on a general purpose architecture. Mechanism A set of Wor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio
Radio is the technology of signaling and communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connected to an antenna which radiates the waves, and received by another antenna connected to a radio receiver. Radio is very widely used in modern technology, in radio communication, radar, radio navigation, remote control, remote sensing, and other applications. In radio communication, used in radio and television broadcasting, cell phones, two-way radios, wireless networking, and satellite communication, among numerous other uses, radio waves are used to carry information across space from a transmitter to a receiver, by modulating the radio signal (impressing an information signal on the radio wave by varying some aspect of the wave) in the transmitter. In radar, used to locate and track objects like aircraft, ships, sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Transmission
Data transmission and data reception or, more broadly, data communication or digital communications is the transfer and reception of data in the form of a digital bitstream or a digitized analog signal transmitted over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fibers, wireless communication using radio spectrum, storage media and computer buses. The data are represented as an electromagnetic signal, such as an electrical voltage, radiowave, microwave, or infrared signal. Analog transmission is a method of conveying voice, data, image, signal or video information using a continuous signal which varies in amplitude, phase, or some other property in proportion to that of a variable. The messages are either represented by a sequence of pulses by means of a line code (''baseband transmission''), or by a limited set of continuously varying waveforms (''passband transmission''), using a digital modulat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Telecommand
A telecommand or telecontrol is a command sent to control a remote system or systems not directly connected (e.g. via wires) to the place from which the telecommand is sent. The word is derived from ''tele'' = remote (Greek), and ''command'' = to entrust/order (Latin). Systems that need remote measurement and reporting of information of interest to the system designer or operator require the counterpart of telecommand, telemetry. The ''telecommand'' can be done in real time or not depending on the circumstances (in space, delay may be of days), as was the case of Marsokhod. Examples *Control of a TV from the sofa *Remote guidance of weapons or missiles *Control of a satellite from a ground station *Flying a radio-controlled airplane Transmission of commands For a Telecommand (TC) to be effective, it must be compiled into a pre-arranged format (which may follow a standard structure), modulated onto a carrier wave which is then transmitted with adequate power to the remote sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury Pressure Gauge
A mercury pressure gauge is a type of manometer using mercury as the working fluid. The most basic form of this instrument is a U-shaped glass tube filled with mercury. More complex versions deal with very high pressure or have better means of filling with mercury. Description The instrument consists of a glass U-tube half-filled with mercury. One end is connected to the vessel whose pressure is being measured. The other may be either left open or sealed. If it is left open, the pressure measured is relative to air pressure, which is variable. If it is sealed, the pressure measured is the absolute pressure. The tube is sealed during manufacture with the sealed end containing a vacuum. Mercury is a useful material to use in a manometer because of its high density. This means that a much shorter column is needed compared to water. For instance, the pressure represented by a column of of water is just under of mercury (mmHg). The pressure is determined by measuring the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dropsonde U
A dropsonde is an expendable weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude over water to measure (and therefore track) storm conditions as the device falls to the surface. The sonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays this data to a computer in the aircraft by radio transmission. Usage Dropsonde instruments are typically the only current method to measure the winds and barometric pressure through the atmosphere and down to the sea surface within the core of tropical cyclones far from land-based weather radar. The data obtained is usually fed via radio into supercomputers for numerical weather prediction, enabling forecasters to better predict the effects and intensity, based on computer-generated models using data gathered from previous storms under simila ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistance Thermometer
Resistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a heat-resistant ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum (Pt), nickel (Ni), or copper (Cu). The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes. RTDs, which have higher accuracy and repeatability, are slowly replacing thermocouples in industrial applications below 600 ° C. Resistance/temperature relationship of metals Common RTD sensing elements for biomedical application constructed of platinum (Pt), nickel (Ni), or copper (Cu) have a repeatable resistance versus temperature relationship (''R'' vs ''T'') and operating temperature range. The ''R'' vs ''T'' relationship is define ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rangefinding Telemeter
A rangefinder (also rangefinding telemeter, depending on the context) is a device used to measure distances to remote objects. Originally optical devices used in surveying, they soon found applications in other fields, such as photography and in the military. They were specially useful for finding the range of a target, such as in naval gunnery and anti-aircraft artillery. The word ''telemeter'' is derived . Designs The first rangefinder telemeter was invented by James Watt in 1769 and put to use in 1771 in surveying canals. Watt called his instrument a micrometer, a term now used with a different meaning in engineering (the micrometer screw gauge). It consisted of two parallel hairs in the focal plane of a telescope eyepiece crossing an upright hair. At the point to be measured, two sliding targets on a surveyor's rod were adjusted to align with the hairs in the telescope. The distance to the rod could then be determined from the distance between the targets on the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermocouple
A thermocouple, also known as a "thermoelectrical thermometer", is an electrical device consisting of two dissimilar electrical conductors forming an electrical junction. A thermocouple produces a temperature-dependent voltage as a result of the Seebeck effect, and this voltage can be interpreted to measure temperature. Thermocouples are widely used as temperature sensors. Commercial thermocouples are inexpensive, interchangeable, are supplied with standard connectors, and can measure a wide range of temperatures. In contrast to most other methods of temperature measurement, thermocouples are self powered and require no external form of excitation. The main limitation with thermocouples is accuracy; system errors of less than one degree Celsius (°C) can be difficult to achieve. Thermocouples are widely used in science and industry. Applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes. Thermocouples are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thomas Johann Seebeck
Thomas Johann Seebeck (; 9 April 1770 – 10 December 1831) was a Baltic German physicist, who, in 1822, observed a relationship between heat and magnetism. Later, in 1823, Ørsted called this phenomenon thermoelectric effect. Seebeck was born in Reval (today Tallinn) to a wealthy Baltic German merchant family. He received a medical degree in 1802 from the University of Göttingen, but preferred to study physics. From 1821 to 1823, Seebeck performed a series of experiments trying to understand Ørsted's findings from 1820. During his experiments, he observed that a junction of dissimilar metals produces a deflexion on a magnetic needle (compass) when exposed to a temperature gradient. Because Ørsted had discovered that an electric current produces a deflexion on a compass transversal to the wire, Seebeck's results were interpreted as a thermoelectric effect. This is now called the Peltier–Seebeck effect and is the basis of thermocouples and thermopiles. Seebeck effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humphry Davy
Sir Humphry Davy, 1st Baronet, (17 December 177829 May 1829) was a British chemist and inventor who invented the Davy lamp and a very early form of arc lamp. He is also remembered for isolating, by using electricity, several elements for the first time: potassium and sodium in 1807 and calcium, strontium, barium, magnesium and boron the following year, as well as for discovering the elemental nature of chlorine and iodine. Davy also studied the forces involved in these separations, inventing the new field of electrochemistry. Davy is also credited to have been the first to discover clathrate hydrates in his lab. In 1799 he experimented with nitrous oxide and was astonished at how it made him laugh, so he nicknamed it "laughing gas" and wrote about its potential anaesthetic properties in relieving pain during surgery. Davy was a baronet, President of the Royal Society (PRS), Member of the Royal Irish Academy (MRIA), Fellow of the Geological Society (FGS), and a mem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Siemens
Sir Carl Wilhelm Siemens (4 April 1823 – 19 November 1883), anglicised to Charles William Siemens, was a German-British electrical engineer and businessman. Biography Siemens was born in the village of Lenthe, today part of Gehrden, near Hanover where his father, Christian Ferdinand Siemens (31 July 1787 – 16 January 1840), a tenant farmer, farmed an estate belonging to the Crown. The Siemens family is an old family of Goslar which has been documented since 1384. His mother was Eleonore Deichmann (1792–8 July 1839), and William, or Carl Wilhelm, was the fourth son of a family of fourteen children. Of his siblings, Ernst Werner Siemens, the fourth child, became a famous electrician and was associated with William in many of his inventions. He was also the brother of Carl Heinrich von Siemens and a cousin of Alexander Siemens. On 23 July 1859, Siemens was married at St James's, Paddington, to Anne Gordon—the youngest daughter of Mr Joseph Gordon, Writer to the Signe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
