Hop (telecommunications)
Encyclopedia
In telecommunication
Telecommunication
Telecommunication is the transmission of information over significant distances to communicate. In earlier times, telecommunications involved the use of visual signals, such as beacons, smoke signals, semaphore telegraphs, signal flags, and optical heliographs, or audio messages via coded...

, the term hop has the following meanings:
  1. The excursion of a radio wave
    Radio Wave
    Radio Wave may refer to:*Radio frequency*Radio Wave 96.5, a radio station in Blackpool, UK...

     from the Earth
    Earth
    Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...

     to the ionosphere
    Ionosphere
    The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...

     and back to the Earth. The number of hops indicates the number of reflections from the ionosphere.
  2. A similar excursion from an earth station
    Earth station
    A ground station, earth station, or earth terminal is a terrestrial terminal station designed for extraplanetary telecommunication with spacecraft, and/or reception of radio waves from an astronomical radio source. Ground stations are located either on the surface of the Earth, or within Earth's...

     to a communications satellite
    Communications satellite
    A communications satellite is an artificial satellite stationed in space for the purpose of telecommunications...

     to another station, counted similarly except that if the return trip is not by satellite, then it's only a half hop.
  3. A waveform
    Waveform
    Waveform means the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.In many cases the medium in which the wave is being propagated does not permit a direct visual image of the form. In these cases, the term 'waveform' refers to the shape of a graph...

     transmitted for the duration of each relocation of the carrier frequency
    Carrier wave
    In telecommunications, a carrier wave or carrier is a waveform that is modulated with an input signal for the purpose of conveying information. This carrier wave is usually a much higher frequency than the input signal...

     of a Frequency-hopping spread spectrum
    Frequency-hopping spread spectrum
    Frequency-hopping spread spectrum is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver...

     system.
  4. To modify a modulated waveform with constant center frequency
    Center frequency
    In electrical engineering and telecommunications, the center frequency of a filter or channel is a measure of a central frequency between the upper and lower cutoff frequencies...

     so that it frequency hops.
  5. With routing
    Routing
    Routing is the process of selecting paths in a network along which to send network traffic. Routing is performed for many kinds of networks, including the telephone network , electronic data networks , and transportation networks...

     a distance in terms of topology and of a length that may be not specified topographically, i.e. one hop is the step from one router to the next, on the path of a packet on any communications network (on the Internet
    Internet
    The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

     often discovered with ping
    Ping
    Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol network and to measure the round-trip time for messages sent from the originating host to a destination computer...

    s or traceroute
    Traceroute
    traceroute is a computer network diagnostic tool for displaying the route and measuring transit delays of packets across an Internet Protocol network. Traceroute is available on most operating systems....

    s). The hop count then is the number of subsequent steps along the path from source to sink. The term "hop" can be seen in some networking based courses referred as "Hand Over Point" in routing terminology.


Some of this text is taken from a public domain entry in Federal Standard 1037C
Federal Standard 1037C
Federal Standard 1037C, titled Telecommunications: Glossary of Telecommunication Terms is a United States Federal Standard, issued by the General Services Administration pursuant to the Federal Property and Administrative Services Act of 1949, as amended....

 in support of MIL-STD-188
MIL-STD-188
MIL-STD-188 is a series of U.S. military standards relating to telecommunications.-Purpose:Faced with “past technical deficiencies in telecommunications systems and equipment and software…that were traced to basic inadequacies in the application of telecommunication standards and to the lack of a...

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The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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