The word keying has a number of meanings Junk Keying Chinese type of ship keying cryptography is the installation of cryptographic key key material into a device. keying telecommunications is a form of modulation where the modulating signal takes one of two or more values at all times. For example on or off , mark or space . The name derives from the Morse code key used for Telegraphy telegraph signalling. keying graphics is an informal term for compositing two full frame images together, by discriminating the visual information into values of color and light. using a key to scratch the paint on car as a form of vandalism . keying social theory is the set of conventions by which a framed activity a fight is transformed into something patterned on this activity, but seen by participants as something quite different play . keying interpreting disambig ... more details
Keying is a family of modulation forms where the modulating signal takes one of two or more values at all times. The goal of keying is to transmit a digital signal over an analogue channel. The name derives from the Morse code key used for Telegraphy telegraph signaling. Modulation is the general technique of shaping a signal to convey information. When a digital message has to be represented as an analogue waveform, the technique and term keying or digital modulation is used. Keying is characterized by the fact that the modulating signal will have a limited number of states or values at all times, to represent the corresponding digital states commonly zero and one, although this might depend on the number of symbol data symbols used . This is in contrast to analogue modulation , where an analogue signal is transmitted over an analogue channel, and where the modulated analogue signal will have an infinite number of meaningful states. Furthermore, note that keying or digital modulation applies to transmitting a digital signal over an analogue passband channel . When a digital signal is to be transmitted over an analogue baseband channel , the modulation technique is termed line coding . Several keying techniques exist, including phase shift keying , frequency shift keying and amplitude shift keying . Bluetooth , for example, uses phase shift keying to exchange information between devices. An overview of keying techniques is given on the modulation page. Category Telecommunications terms telecomm term stub ... more details
Junk Keying Infobox ship career Hide header Ship country Ship flag Ship name Keying Ship ordered ... The Junk Keying zh c p q y ng , named after the Manchu official Qiying the English name ... and England between 1846 and 1848. Keying had been purchased in August 1846 in secrecy by English ... Kellett during her travel. Junk Keying left Hong Kong in December 1846. She rounded the Cape of Good ... Keying moored in New York harbour in 1847 watercolor on canvas, c. 1853 1855, Museum of the City of New York . The Keying was the first ship from China to visit New York. She moored off the Battery ... fanfare. The Cantonese crew of Keying were understandably angry as they only signed on for an eight ... of them were exhibited by P.T. Barnum on his version of Keying that he had built in Hoboken he claimed he had it towed from China .The 26 crew that left Keying returned to Canton on board the Candace 6 October 1847. The crew of the hoax Keying were described by the Brooklyn Eagle as one third white and two thirds negroes or mulatoes so probably no Chinese from the real Keying were ever on the P.T. ... were paying 25 cents to board the ship and observe its design and crew. Keying also moored in Boston ... visit Image KeyingMedal.jpg thumb 300px The medal made for the arrival of the Junk Keying in England ... steam packet of the period The Keying next visited Boston, whence she sailed direct for London on the 17th ... the visits to the Keying as follows The ROYAL CHINESE JUNK KEYING manned by a Chinese Crew. Visitors ... in the most approved style of the Celestial Empire. Collection of Chinese Curiosities, &c. The Keying ... of Guangzhou Canton . The Times . The Keying was towed from London to the river Mersey by the steam ... with text click image for translation . The ship also is illustrated above the text. Junk Keying ... of Junk Keying is visible since September 2005 in the new Hong Kong Maritime Museum , in Stanley ... shows with its use of the contemporary Currier print made during the Keying s visit to the USA ... more details
Modulation techniques On off keying OOK the simplest form of amplitude shift keying ASK modulation that represents digital data as the presence or absence of a carrier wave . In its simplest form, the presence of a carrier for a specific duration represents a Binary numeral system binary one, while its absence for the same duration represents a binary zero. Some more sophisticated schemes vary these durations to convey additional information. It is analogous to unipolar encoding line code . On off keying is most commonly used to transmit Morse code over Radio frequency radio frequencies referred to as CW continuous wave operation , although in principle any digital encoding scheme may be used. OOK has been used in the ISM band s to transfer data between computer s, for example. OOK is more Spectral efficiency spectrally efficient than FSK, but more sensitive to noise. In addition to RF carrier waves, OOK is also used in optical communication systems e.g. IrDA . In aviation, some possibly unmanned airports have equipment that let pilots key their VHF radio a number of times in order to request an Automatic Terminal Information Service broadcast, or Pilot Controlled Lighting turn on runway lights . See also Unipolar encoding External links http www.maxim ic.com appnotes.cfm an pk 4439 CMP ELK12 Application Note I m OOK. You re OOK? Morse code state uncollapsed Bit encoding state uncollapsed Category Quantized radio modulation modes Category Fiber optic communications Category Amateur radio ar bn ko it On off keying ja ... more details
Orphan date December 2009 In wireless technology, Handover Keying Hokey refers to maintaining a secure connection seamlessly while migrating from one wireless network to another. External links IETF http www.ietf.org html.charters hokey charter.html Working Group http www.networkworld.com news 2007 073007 ietf qa.html Interview with Russ Housley , chair of the Internet Engineering Task Force Category Wireless networking Wireless stub ... more details
shift keying AFSK is a modulation technique by which digital data is represented by changes in the frequency .... AFSK differs from regular frequency shift keying in performing the modulation at baseband frequencies ... audio frequency shift keying to send and receive data, up to rates of about 1200 bits per second ... digital time signal encoded using AFSK modulation. References Reflist See also Amplitude shift keying ASK Continuous phase frequency shift keying CPFSK Dual tone multi frequency DTMF , another encoding ... frequency shift keying MFSK Orthogonal frequency division multiplexing OFDM Phase shift keying PSK Federal ... pp.pdf dFSK Distributed Frequency Shift Keying Modulation in Dense Sensor Networks Category Quantized ... it Frequency shift keying mk Frequency shift keying nl Frequentieverschuivingsmodulatie ja pl Frequency Shift Keying pt FSK ru fi FSK zh ... more details
continuously and linearly changes. Gaussian minimum shift keying In digital communication , Gaussian minimum shift keying or GMSK is a continuous phase frequency shift keying modulation modulation scheme . It is similar to standard minimum shift keying MSK however the digital data stream ... Pasupathy, Minimum Shift Keying A Spectrally Efficient Modulation , IEEE Communications Magazine ... & illustrations Aerospace Reflist Category Quantized radio modulation modes de Minimum Shift Keying pl MSK es GMSK fr Gaussian minimum shift keying ja ru fi GMSK zh it Minimum shift Keying ... more details
Gaussian Frequency Shift Keying GFSK is a type of Frequency Shift Keying modulation that uses a Gaussian filter to smooth positive negative frequency deviations, which represent a binary 1 or 0. It is used by DECT , Bluetooth ref Sweeney, D. An introduction to bluetooth a standard for short range wireless networking Proceedings. 15th Annual IEEE International ASIC SOC Conference, Rochester, NY, USA, 25 28 Sept. 2002 , pp. 474 475. 2002. http ieeexplore.ieee.org xpls abs all.jsp?arnumber 1158106 ref , Cypress WirelessUSB , Nordic Semiconductor ref Nordic Semiconductor. http www.nordicsemi.com files Product data sheet Preliminary Product Specification nRF24LU1P v1 2.pdf nRF24LU1 Preliminary Product Specification v1.2 ref , Texas Instruments LPRF , z wave and Wavenis devices. For basic data rate Bluetooth the minimum deviation is 115 kHz. Generalization In a GFSK modulator, everything is the same as an Frequency shift keying FSK modulator except that before the baseband pulses 1, 1 go into the FSK modulator, it is passed through a gaussian filter to make the pulse smoother so to limit its spectral width. Gaussian filtering is one of the very standard ways for reducing the spectral width, it is called pulse shaping . If we use 1 for math f c f d math and 1 for math f c f d math , once when we jump from 1 to 1 or 1 to 1, the modulated waveform changes rapidly, which introduces large out of band spectrum. If we change the pulse going from 1 to 1 as 1, .98, .93 ..... .96, .99, 1, and we use this smoother pulse to modulate the carrier, the out of band spectrum will be reduced. ref http www.palowireless.com infotooth knowbase radio 109.asp www.palowireless.com GFSK Differences & Advantages over FSK Modulation ref References Reflist telecomm stub wireless stub Category Quantized radio modulation modes de Gaussian Frequency Shift Keying es Modulaci n por desplazamiento de frecuencia gausiana ko pl GFSK ... more details
Refimprove date August 2008 Modulation techniques Amplitude and Phase shift keying or Asymmetric Phase shift keying , APSK , is a digital modulation scheme that conveys Data Uses of data in computing data by changing, or modulating, both the amplitude and the Phase waves phase of a reference Signal information theory signal the carrier wave . In other words, it combines both Amplitude shift keying ASK and Phase shift keying PSK to increase the Symbol data symbol set . It can be considered as a superclass of Quadrature amplitude modulation QAM . The advantage over conventional QAM, for example 16 QAM, is lower number of possible amplitude levels, resulting in fewer problems with non linear amplifiers. Applications The DVB S2 specification permits the use of 16APSK and 32APSK modes, allowing 16 and 32 different symbols respectively and are intended for mainly professional, semi linear applications. They can be also used for broadcasting but they require a higher level of available Carrier to noise ratio C N and an adoption of advanced Predistortion pre distortion methods in the uplink station in order to minimize the effect of transponder non linearity. Image with unknown copyright status removed Image M APSK.PNG Figure Bit mapping into constellations see Ref.2 References http www.ebu.ch en technical trev trev 300 morello.pdf DVB S2 ready for lift off , article in the European Broadcasting Union EBU technical review http public.ccsds.org publications archive 131x2o1.pdf Flexible Serially Concatenated Convolutional Turbo Codes with Near Shannon bound performance for telemtery applications , CCSDS 131.2 O 1. Category Quantized radio modulation modes electronics stub ca Modulaci per despla ament d amplitud i fase de Amplituden und Phasenmodulation es Modulaci n por desplazamiento de amplitud y fase ... more details
Modulation techniques Amplitude shift keying ASK is a form of modulation that represents digital data as variations in the amplitude of a carrier wave . The amplitude of an analog carrier Signal electrical engineering signal varies in accordance with the bit stream modulating signal , keeping frequency and Phase waves phase constant. The level of amplitude can be used to represent Binary numeral system binary logic 0s and 1s. We can think of a carrier signal as an ON or OFF switch. In the modulated signal, logic 0 is represented by the absence of a carrier, thus giving OFF ON keying operation and hence the name given. Like Amplitude modulation AM , ASK is also linear and sensitive to atmospheric noise, distortions, propagation conditions on different routes in PSTN , etc. Both ASK modulation and demodulation processes are relatively inexpensive. The ASK technique is also commonly used to transmit digital data over optical fiber. For LED transmitters, binary 1 is represented by a short pulse of light and binary 0 by the absence of light. Laser transmitters normally have a fixed bias current that causes the device to emit a low light level. This low level represents binary 0, while a higher amplitude lightwave represents binary 1. Encoding The simplest and most common form of ASK operates as a switch, using the presence of a carrier wave to indicate a Binary numeral system binary one and its absence to indicate a binary zero. This type of modulation is called on off keying , and is used ... of amplitude shift keying require a high signal to noise ratio for their recovery, as by their nature ... Nyquist function . See also Frequency shift keying Phase shift keying Nyquist ISI criterion Intersymbol ... an pk 2815 CMP WP 21 Calculating the Sensitivity of an Amplitude Shift Keying ASK Receiver DEFAULTSORT Amplitude Shift Keying Category Quantized radio modulation modes Category Applied probability Category ... shift keying ja pl ASK pt Modula o por chaveamento de amplitude ru ... more details
Complementary Code Keying CCK is a modulation scheme used with wireless network s WLANs that employ the IEEE 802.11b specification. In 1999, CCK was adopted to supplement the Barker code in wireless digital networks to achieve data rate higher than 2 Mbit s at the expense of shorter distance. This is due to the shorter chipping sequence in CCK 8 bits versus 11 bits in Barker code that means less spreading to obtain higher data rate but more susceptible to narrowband interference resulting in shorter radio transmission range. Beside shorter chipping sequence, CCK also has more chipping sequences to encode more bits 4 chipping sequences at 5.5 Mbit s and 64 chipping sequences at 11 Mbps increasing the data rate even further. The Barker code, however, only has a single chipping sequence. Complementary sequences Complementary codes , first introduced by Marcel J. E. Golay Golay in 1961 are sets of finite sequences of equal length, such that the number of pairs of identical elements with any given separation in one sequence is equal to the number of pairs of unlike elements having the same separation in the other sequences. The complementary codes first discussed by Golay were pairs of binary complementary codes and he noted that when the elements of a code of length N were either 1 or 1 it followed immediately from their definition that the sum of their respective autocorrelation sequences was zero at all points except for the zero shift where it is equal to K N. K being the number of code words in the set . CCK is a variation and improvement on, M ary Orthogonal Keying and utilises polyphase complementary codes . They were developed by Lucent Technologies and Harris Semiconductor ... 1999, 18.4.6.5 DEFAULTSORT Complementary Code Keying Category Quantized radio modulation modes Category Telecommunications terms Category IEEE 802.11 de Complementary Code Keying fr Complementary Code Keying ... more details
Cleanup date May 2009 Modulation techniques Phase shift keying PSK is a digital modulation scheme that conveys ... successive phases, it is termed differential phase shift keying DPSK . DPSK can be significantly ... ly represented data Amplitude shift keying ASK Frequency shift keying FSK Phase shift keying ... information &mdash Differential encoding differential schemes, Phase shift keying Differential phase shift keying .28DPSK.29 some of which do not need a reference carrier to a certain extent . A convenient ... and sine waves. Two common examples are binary phase shift keying Phase shift keying Binary phase shift keying BPSK BPSK which uses two phases, and quadrature phase shift keying Phase shift keying Quadrature phase shift keying QPSK QPSK which uses four phases, although any number of phases ... rate of 11 Mbit s, QPSK is employed, but has to be coupled with complementary code keying . The higher ... is sufficiently robust. Bluetooth 1 modulates with Minimum shift keying Gaussian minimum shift keying , a binary scheme, so either modulation choice in version 2 will yield a higher data rate. A similar ... . Binary phase shift keying BPSK Image BPSK Gray Coded.svg 200px right thumb Constellation diagram example for BPSK. BPSK also sometimes called PRK, Phase Reversal Keying, or 2PSK is the simplest form of phase shift keying PSK . It uses two phases which are separated by 180 and so can also ... symbol, this is also the symbol error rate. By Loxodonta Quadrature phase shift keying QPSK Image ... quadrature phase shift keying OQPSK is a variant of phase shift keying modulation using 4 different values of the phase to transmit. It is sometimes called Staggered quadrature phase shift keying SQPSK ... shift keying DPQPSK or dual polarization QPSK involves the polarization multiplexing of two different ... of the union bound to the signal constellation. Differential phase shift keying DPSK Differential encoding main differential coding Differential phase shift keying DPSK is a common form ... more details
Modulation techniques Multiple frequency shift keying MFSK is a variation of frequency shift keying FSK that uses more than two frequencies. http sharon.esrac.ele.tue.nl mirrors zl1bpu MFSK is a form of M ary orthogonal modulation , where each symbol consists of one element from an alphabet of orthogonal waveforms. M, the size of the alphabet, is usually a power of two so that each symbol represents log sub 2 sub M bits. M is usually between 2 and 64 Error Correction is generally also used How it works Like other M ary orthogonal schemes, the required Eb N0 E sub b sub N sub 0 sub ratio for a given probability of error decreases as M increases without the need for multisymbol coherent detection. In fact, as M approaches infinity the required E sub b sub N sub 0 sub ratio decreases asymptotically to the Shannon limit of 1.6 decibel dB . However this decrease is slow with increasing M, and large values are impractical because of the exponential increase in required bandwidth. Typical values in practice range from 4 to 64, and MFSK is combined with another forward error correction scheme to provide additional systematic coding gain. Types Defined examples of a multiple frequency shift keying system include dual tone multi frequency DTMF , which is used in touch tone phones and the Multi frequency trunk signals used in Twentieth Century telephone exchanges. These signals are distinctive when received auraly. Their main feature is a rapid succession of tones with almost musical quality. ref cite web url http xoomer.alice.it ham radio manuals scanning Digitalsignalsfaq.html author Scalsky, S. and Chace, M. title Digital Signals Frequently Asked Questions Version 5 , Section 1 D ... web author Dehio, Leif title MFSK systems Multi Frequency Shift Keying url http www.signals.taunus.de ... 01 06 refend DEFAULTSORT Multiple Frequency Shift Keying Category Quantized radio modulation modes Category Telephony signals it Multiple frequency shift keying pl MFSK ... more details
Mergeto Phase shift keying OQPSK date March 2009 Orphan date February 2009 In telecommunication , filtered symmetric differential phase shift keying FSDPSK is a method of encoding information for digital transmission telecommunications transmission in which A 0 bit is encoded as a 90 change in the carrier wave carrier phase waves phase , and a 1 bit is encoded as a 90 change in the carrier phase Abrupt phase transitions are smoothed by filtering or other functionally equivalent pulse shaping techniques. See also Phase shift keying References FS1037C Category Communication circuits telecomm stub ... more details
Character generation may refer to Character creation , the process of creating a character for a role playing game Character generator , a device or software that produces text for keying into a video stream disambig ... more details
Unreferenced date June 2009 Keymat keying material is a generic term for any usually Classified information classified material used in the process of loading key cryptography key s into a cryptographic device. Category Key management crypto stub ... more details
In telecommunication , the term facsimile converter has the following meanings 1. In a facsimile receiver , a device that changes the Signalling telecommunication signal modulation from frequency shift keying FSK to amplitude modulation AM . 2. In a facsimile transmitter , a device that changes the signal modulation from amplitude modulation AM to frequency shift keying FSK . References FS1037C MS188 Category Communication circuits telecomm stub ... more details
Unreferenced date December 2009 Orphan date March 2008 Higher order modulation is a type of digital modulation usually with an order of 4 or higher. Examples quadrature phase shift keying QPSK , m ary quadrature amplitude modulation m QAM , etc. See also phase shift keying modulation order DEFAULTSORT Higher Order Modulation Category Quantized radio modulation modes ... more details
orphan date June 2010 Other uses Break disambiguation Break In locksmithing , a break in the pin s is a separation in one or more sections of the pin used to code encode the lock for a specific Key lock key or set of keys in a Key lock Master key master keying system. job stub Category Locksmithing ... more details
In telecommunication , receive after transmit time delay is the time interval between a the instant of keying off the local transmitter to stop transmitting and b the instant the local receiver output has increased to 90 of its steady state value in response to an rf Signalling telecommunication signal from a distant transmitter. The rf signal from the distant transmitter must exist at the local receiver input prior to, or at the time of, keying off the local transmitter. Receive after transmit time delay applies only to half duplex operation . References FS1037C MS188 Category Telecommunications ... more details
APK may refer to APK file format , as in filename.apk , Android Package, a packaging file format for the Android operating system Afrikaanse Protestantse Kerk , the whites only Calvinist church in South Africa Algemene Periodieke Keuring , the Vehicle inspection The Netherlands vehicle inspection in The Netherlands Amplitude shift keying , see Amplitude and phase shift keying Apopka High School , see Apopka High School Arbetarpartiet Kommunisterna , see Communist Party of Sweden 1995 Arbejderpartiet Kommunisterne , see Workers Communist Party Denmark disambig de APK es APK fr APK it APK nl APK sv APK ... more details
Refimprove date June 2009 Rivet Amber , an Boeing RC 135 RC 135E , 62 4137, operating out of Shemya Shemya AFB , went down in the Bering Sea on June 5, 1969. Despite a thorough search of the area, no wreckage and no survivors were ever found. The best theory is that the plane suffered some sort of catastrophic mechanical failure, as the last radio contact from the aircraft mentioned vibration in flight . Rivet Amber was returning to Eielson Air Force Base Eielson AFB for maintenance with a crew of 19 on board. Citation needed date June 2009 Last Radio Transmission The last radio contact with Rivet Amber began about 45 minutes after takeoff at 0936 Local 1736 Coordinated Universal Time Zulu . Rivet Amber was under the call sign Irene 92. 1736 Zulu Rivet Amber Elmendorf Airways, Elmendorf Airways, Irene 92, Irene 92, over. Elmendorf AFB Irene 92, Elmendorf, Go Ahead. RA Elmendorf Airways, Irene 92 experiencing vibration In flight. Not certain of the Emergency. We have the aircraft under control, Irene 92. 1737 Zulu EAFB This is Elmendorf. You say you re not declaring an Emergency. Is that Charlie? RA Keying XMTR, followed by heavy breathing RA Roger Ahh Keying XMTR Ahh Keying XMTR, then silence RA Crew Go To Oxygen. EAFB This is Elmendorf. Say again? Irene 92, Elmendorf? RA Keying XMTR EAFB Irene 92, Elmendorf? 1738 Zulu RA Keying XMTR 1739 Zulu EAFB Irene 92, Irene 92, Elmendorf, Elmendorf RA Keying XMTR RA Keying XMTR RA Keying XMTR Unidentified key clicks Keying XMTR continued until 1822 Zulu. No further positive contact with Rivet Amber was made after 1737 Zulu. Post Incident Unable to make contact with Rivet Amber, Col. Leslie W. Brockwell, commander of the 6th Strategic Wing, initiated a search and rescue. Both planes and Coast Guard searched the waters from Shemya to the Alaska mainland. For two weeks, the water was patrolled for any sign of the plane or survivors, but nothing was ever found. The entire crew was presumed lost at sea. List of Crew Lt Col Charles ... more details
Expand list date August 2008 The following is a list of the modes of communication used by amateur radio operator s. Analog Amplitude Modulation AM Sideband Double Sideband Suppressed Carrier DSB SC Independent sideband Independent Sideband ISB Single sideband modulation Single Sideband SSB Amplitude modulation equivalent Amplitude Modulation Equivalent AME Frequency Modulation FM Phase Modulation PM Continuous Wave C ontinuous W ave CW Image Modes Amateur television A mateur T ele v ision , also known as Fast Scan television ATV Slow scan television S low S can T ele v ision SSTV Fax Facsimile Digital Most amateur digital modes are transmitted by inserting audio into the microphone input of a radio and using an analog scheme, such as amplitude modulation AM , frequency modulation FM , or single sideband modulation SSB . Automatic Link Establishment ALE A utomatic L ink E stablishment AMTOR AM ateur T eleprinting O ver R adio AMTOR D Star Echolink GTOR Hellschreiber , also referred to as either Feld Hell , or Hell Discrete multi tone modulation modes such as MT63 M ulti T one 63 MT63 Multiple frequency shift keying M ultiple F requency S hift K eying MFSK modes such as WSJT Amateur radio software FSK441, JT6M, JT65 , and Olivia MFSK Packet Radio AX25 Automatic Packet Reporting System A utomatic P acket R eporting S ystem APRS PACTOR Phase shift keying P hase S hift K eying 31 baud BPSK binary phase shift keying PSK31 31 baud QPSK quadrature phase shift keying QPSK31 63 baud BPSK binary phase shift keying PSK63 63 baud QPSK quadrature phase shift keying QPSK63 CLOVER Spread spectrum SITOR Si mplex T eletype O ver R adio SITOR RTTY R adio T ele ty pe RTTY Automatic Link Establishment 8FSK 8 ary F requency S hift K eying Modes by Activity The following modes use no one specific modulation scheme but rather are classified by the activity of the communication. EME communications E arth M oon E arth EME IRLP I nternet R adio L inking P roject IRLP QRP operation Low Transm ... more details
Orphan date March 2009 Charles Alfred Kellett born circa 1820 in Plymouth , Devon shire ref Birth Certificate for Sydney S. Kellett, Reg. No. 1857 009581, New South Wales Registrar of Births, Deaths and Marriages. Certified copy in possession of author. ref was a United Kingdom British Master Mariner famous for having sailed the Chinese Junk Keying from China , around the Cape of Good Hope to the United States and England between 1846 and 1848. Notes reflist After this adventure, Kellet reportedly migrated to India. See also Junk Keying Persondata Metadata see Wikipedia Persondata . NAME Kellet, Charles Alfred ALTERNATIVE NAMES SHORT DESCRIPTION DATE OF BIRTH 1820 PLACE OF BIRTH DATE OF DEATH PLACE OF DEATH DEFAULTSORT Kellet, Charles Alfred Category British sailors Category Nautical captains Category 1820 births Category Year of death missing UK bio stub ... more details
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