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Keyboard of a German manual typewriter (early 20th century), with Shift keys labelled "Umschalter" ("switch") Keyboard symbol for "Level 2 Select" (i.e. "Shift") The keyboard symbol for the Shift key (which is called Level 2 Select key in the international standard series ISO/IEC 9995) is given in ISO/IEC 9995-7 as symbol 1, and in ISO 7000 “Graphical symbols for use on equipment” as a ...
Phase-shift keying ( PSK) is a digital modulation process which conveys data by changing (modulating) the phase of a constant frequency carrier wave. The modulation is accomplished by varying the sine and cosine inputs at a precise time. It is widely used for wireless LANs, RFID and Bluetooth communication. Any digital modulation scheme uses a ...
In digital modulation, minimum-shift keying ( MSK) is a type of continuous-phase frequency-shift keying that was developed in the late 1950s by Collins Radio employees Melvin L. Doelz and Earl T. Heald. [1] Similar to OQPSK, MSK is encoded with bits alternating between quadrature components, with the Q component delayed by half the symbol period.
QWERTY ( / ˈkwɜːrti / KWUR-tee) is a keyboard layout for Latin-script alphabets. The name comes from the order of the first six keys on the top letter row of the keyboard: Q W E R T Y. The QWERTY design is based on a layout included in the Sholes and Glidden typewriter sold via E. Remington and Sons from 1874.
Amplitude-shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. In an ASK system, a symbol , representing one or more bits , is sent by transmitting a fixed-amplitude carrier wave at a fixed frequency for a specific time duration.
v. t. e. On–off keying ( OOK) denotes the simplest form of amplitude-shift keying (ASK) modulation that represents digital data as the presence or absence of a carrier wave. [1] In its simplest form, the presence of a carrier for a specific duration represents a binary one, while its absence for the same duration represents a binary zero.
e. Multiple frequency-shift keying ( MFSK) is a variation of frequency-shift keying (FSK) that uses more than two frequencies. 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 ...
Baudot developed his first multiplexed telegraph in 1872 [2] [3] and patented it in 1874. [3] [4] In 1876, he changed from a six-bit code to a five-bit code, [3] as suggested by Carl Friedrich Gauss and Wilhelm Weber in 1834, [2] [5] with equal on and off intervals, which allowed for transmission of the Roman alphabet, and included punctuation and control signals.