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Quindar Tones
Quindar tones, most often referred to as the "beeps" that were heard during the American Apollo space missions, were a means by which remote transmitters on Earth were turned on and off so that the capsule communicator (CapCom) could communicate with the crews of the spacecraft. It was a means of in-band signaling to simulate the action of the push-to-talk and release-to-listen (often referred to as PTT) button commonly found on two-way radio systems and walkie-talkies. Rationale When Mission Control (in Houston, Texas) wanted to talk to astronauts, the capsule communicator (CapCom) pushed a button (push-to-talk, or PTT) that turned on the transmitter, then spoke, then released the button. When the transmitter is local, this is easy to arrange: the transmitter is connected directly to the PTT button. But to stay in continuous contact with the astronauts as they orbit the Earth, or travel to the Moon, NASA The National Aeronautics and Space Administration (NASA ) is an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SpaceX Crew-1
SpaceX Crew-1 (was also known as USCV-1 or simply Crew-1) was the first operational crewed flight of a Crew Dragon spacecraft, and the maiden flight of the Crew Dragon ''Resilience'' spacecraft. It was also the second crewed orbital flight launch by the United States since that of STS-135 in July 2011. ''Resilience'' launched on 16 November 2020 at 00:27:17 UTC on a Falcon 9 from Kennedy Space Center Launch Complex 39A (LC-39A), carrying NASA astronauts Michael Hopkins, Victor Glover and Shannon Walker along with JAXA astronaut Soichi Noguchi, all members of the Expedition 64 crew. The mission was the second overall crewed orbital flight of the Crew Dragon. Crew-1 was the first operational mission to the International Space Station (ISS) in the Commercial Crew Program. Originally designated "USCV-1" by NASA in 2012, the launch date was delayed several times from the original date of November 2016. The mission was scheduled to depart the ISS on 28 April 2021, but due to wea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice-operated Switch
In telecommunications, a voice operated switch, also known as VOX or voice-operated exchange, is a switch that operates when sound over a certain threshold is detected. It is usually used to turn on a transmitter or recorder when someone speaks and turn it off when they stop speaking. It is used instead of a push-to-talk button on transmitters or to save storage space on recording devices. On cell phones A mobile phone, cellular phone, cell phone, cellphone, handphone, hand phone or pocket phone, sometimes shortened to simply mobile, cell, or just phone, is a portable telephone that can make and receive calls over a radio frequency link whil ..., it is used to save battery life. Intercom systems that use a speaker in a room as both a speaker and a microphone will often use VOX on the main console to switch the audio direction during a conversation. The circuit usually includes a delay between the sound stopping and switching direction, to avoid the circuit turning off during ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repeater
In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Some types of repeaters broadcast an identical signal, but alter its method of transmission, for example, on another frequency or baud rate. There are several different types of repeaters; a telephone repeater is an amplifier in a telephone line, an optical repeater is an optoelectronic circuit that amplifies the light beam in an optical fiber cable; and a radio repeater is a radio receiver and transmitter that retransmits a radio signal. A broadcast relay station is a repeater used in broadcast radio and television. Overview When an information-bearing signal passes through a communication channel, it is progressively degraded due to loss of power. For example, when a telephone call passes through a wire telephone line, some of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Half-duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX). In a full-duplex system, both parties can communicate with each other simultaneously. An example of a full-duplex device is plain old telephone service; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party. There is a two-way communication channel between them, or more strictly speaking, there are two communication channel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Courtesy Tone
Courtesy (from the word ''courteis'', from the 12th century) is gentle politeness and courtly manners. In the Middle Ages in Europe, the behaviour expected of the nobility was compiled in courtesy books. History The apex of European courtly culture was reached in the Late Middle Ages and the Baroque period (i.e. roughly the four centuries spanning 1300–1700). The oldest courtesy books date to the 13th century, but they become an influential genre in the 16th, the most influential of them being ''Il Cortegiano'' (1508), which not only covered basic etiquette and decorum but also provided models of sophisticated conversation and intellectual skill. The royal courts of Europe did, of course, persist well into the 18th century (and to some limited extent to the present day), but in the 18th century, the notion of ''courtesy'' was replaced by that of '' gallantry'', referring to an ideal emphasizing the display of affected sensitivity in direct contrast with the ideals of self-de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Astronauts
An astronaut (from the Ancient Greek (), meaning 'star', and (), meaning 'sailor') is a person trained, equipped, and deployed by a human spaceflight program to serve as a commander or crew member aboard a spacecraft. Although generally reserved for professional space travelers, the term is sometimes applied to anyone who travels into space, including scientists, politicians, journalists, and tourists. "Astronaut" technically applies to all human space travelers regardless of nationality. However, astronauts fielded by Russia or the Soviet Union are typically known instead as cosmonauts (from the Russian "kosmos" (космос), meaning "space", also borrowed from Greek). Comparatively recent developments in crewed spaceflight made by China have led to the rise of the term taikonaut (from the Mandarin "tàikōng" (), meaning "space"), although its use is somewhat informal and its origin is unclear. In China, the People's Liberation Army Astronaut Corps astronauts and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earth
Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surface is made up of the ocean, dwarfing Earth's polar ice, lakes, and rivers. The remaining 29% of Earth's surface is land, consisting of continents and islands. Earth's surface layer is formed of several slowly moving tectonic plates, which interact to produce mountain ranges, volcanoes, and earthquakes. Earth's liquid outer core generates the magnetic field that shapes the magnetosphere of the Earth, deflecting destructive solar winds. The atmosphere of the Earth consists mostly of nitrogen and oxygen. Greenhouse gases in the atmosphere like carbon dioxide (CO2) trap a part of the energy from the Sun close to the surface. Water vapor is widely present in the atmosphere and forms clouds that cover most of the planet. More sola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Voice
The human voice consists of sound made by a human being using the vocal tract, including talking, singing, laughing, crying, screaming, shouting, humming or yelling. The human voice frequency is specifically a part of human sound production in which the vocal folds (vocal cords) are the primary sound source. (Other sound production mechanisms produced from the same general area of the body involve the production of unvoiced consonants, clicks, whistling and whispering.) Generally speaking, the mechanism for generating the human voice can be subdivided into three parts; the lungs, the vocal folds within the larynx (voice box), and the articulators. The lungs, the "pump" must produce adequate airflow and air pressure to vibrate vocal folds. The vocal folds (vocal cords) then vibrate to use airflow from the lungs to create audible pulses that form the laryngeal sound source. The muscles of the larynx adjust the length and tension of the vocal folds to 'fine-tune' pit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passband
A passband is the range of frequencies or wavelengths that can pass through a filter. For example, a radio receiver contains a bandpass filter to select the frequency of the desired radio signal out of all the radio waves picked up by its antenna. The passband of a receiver is the range of frequencies it can receive when it is tuned into the desired frequency (channel). A bandpass-filtered signal (that is, a signal with energy only in a passband), is known as a bandpass signal, in contrast to a baseband signal. Filters In telecommunications, optics, and acoustics, a passband (a band-pass filtered signal) is the portion of the frequency spectrum that is transmitted (with minimum relative loss or maximum relative gain) by some filtering device. In other words, it is a ''band'' of frequencies which ''pass''es through some filter or a set of filters. The accompanying figure shows a schematic of a waveform being filtered by a bandpass filter consisting of a highpass an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YouTube
YouTube is a global online video sharing and social media platform headquartered in San Bruno, California. It was launched on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim. It is owned by Google, and is the second most visited website, after Google Search. YouTube has more than 2.5 billion monthly users who collectively watch more than one billion hours of videos each day. , videos were being uploaded at a rate of more than 500 hours of content per minute. In October 2006, YouTube was bought by Google for $1.65 billion. Google's ownership of YouTube expanded the site's business model, expanding from generating revenue from advertisements alone, to offering paid content such as movies and exclusive content produced by YouTube. It also offers YouTube Premium, a paid subscription option for watching content without ads. YouTube also approved creators to participate in Google's AdSense program, which seeks to generate more revenue for both parties. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 used i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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