On-off keying

On-off keying
Passband modulation v · d · e
Analog modulation
AM · SSB · QAM · FM · PM · SM
Digital modulation
FSK · MFSK · ASK · OOK · PSK · QAM
MSK · CPM · PPM · TCM · SC-FDE
Spread spectrum
CSS · DSSS · FHSS · THSS
See also: Demodulation, modem,
line coding, PAM, PWM, PCM

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 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 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 bands to transfer data between computers, for example.

OOK is more 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 turn on runway lights.

See also

External links

v · International Morse code
Transmission methods
Notable signals
Other writing systems
in Morse code
v · d · eLine coding (digital baseband transmission)
Main articles
Unipolar encoding · Bipolar encoding · On-off keying
 Biphase Mark Code.svg
Basic line codes
Extended line codes
Optical line codes
Carrier-Suppressed Return-to-Zero · Alternate-Phase Return-to-Zero
See also: Baseband · Baud · Bit rate · Digital signal · Digital transmission · Ethernet physical layer · Pulse modulation methods · Pulse-amplitude modulation (PAM) · Pulse code modulation (PCM) · Serial communication · Category:Line codes

Wikimedia Foundation. 2010.

Игры ⚽ Нужно сделать НИР?

Look at other dictionaries:

  • On-Off Keying — Amplitudenumtastung (engl. Amplitude Shift Keying (ASK)) ist eine digitale Modulationsart. Dabei wird die Amplitude des Trägersignals verändert, um verschiedene Werte zu übertragen. Die einfachste Form der Amplitudentastung ist das sogenannte On… …   Deutsch Wikipedia

  • Keying — The word keying has a number of meanings:*Junk Keying Chinese type of ship *keying (cryptography) is the installation of key material into a device. *keying (telecommunications) is a form of modulation where the modulating signal takes one of two …   Wikipedia

  • keying — I. ˈkēiŋ ē.ēŋ noun ( s) Etymology: key (I) + ing (n. suffix) : the process of turning an electronic circuit off or on either manually or automatically such keying represents the simplest possible form of modulation, and is applicable to all kinds …   Useful english dictionary

  • Keying — Key Key, v. t. [imp. & p. p. {Keved}; p. pr. & vb. n. {Keying}.] 1. To fasten or secure firmly; to fasten or tighten with keys or wedges. Francis. [1913 Webster] 2. (Computers) To enter (text, data) using keys, especially those on a keyboard; to… …   The Collaborative International Dictionary of English

  • 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 varies in accordance with the bit stream (modulating signal), keeping frequency and phase… …   Wikipedia

  • Amplitude Shift Keying — Amplitudenumtastung (engl. Amplitude Shift Keying (ASK)) ist eine digitale Modulationsart. Dabei wird die Amplitude des Trägersignals verändert, um verschiedene Werte zu übertragen. Die einfachste Form der Amplitudentastung ist das sogenannte On… …   Deutsch Wikipedia

  • Junk Keying — The Junk Keying (zh cp|c=耆英|p=qíyīng, literally Elder and Brave ; the English name is based on Cantonese pronunciation) was a three masted, 800 ton Foochow Chinese trading junk which sailed from China around the Cape of Good Hope to the United… …   Wikipedia

  • Amplitude and phase-shift keying — or Asymmetric Phase shift keying, (APSK), is a digital modulation scheme that conveys data by changing, or modulating, both the amplitude and the phase of a reference signal (the carrier wave). In other words, it combines both Amplitude shift… …   Wikipedia

  • Key (keying) — RadioPP Turning a sound source on or off from the console …   Audio and video glossary

  • Modulation — For musical change of key, see Modulation (music). For other uses, see Modulation (disambiguation). Passband modulation v · d · e …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”