In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted. Most radio systems in the 20th century used frequency modulation (FM) or amplitude modulation (AM) for radio broadcast.
Time-division multiple access (TDMA) is a channel access method for shared-medium networks. It allows several users to share the same frequency channel by dividing the signal into different time slots. The users transmit in rapid succession, one after the other, each using its own time slot. This allows multiple stations to share the same transmission medium while using only a part of its channel capacity. TDMA is used in the digital 2G cellular systems such as Global System for Mobile Communications (GSM), IS-136, Personal Digital Cellular (PDC) and iDEN, and in the Digital Enhanced Cordless Telecommunications (DECT) standard for portable phones. It is also used extensively in satellite systems, combat-net radio systems, and passive optical network (PON) networks for upstream traffic from premises to the operator. For usage of Dynamic TDMA packet mode communication, see below.
In telecommunications, direct-sequence spread spectrum (DSSS) is a spread spectrum modulation technique used to reduce overall signal interference. The spreading of this signal makes the resulting wideband channel more noisy, allowing for greater resistance to unintentional and intentional interference.
In telecommunications and computer networks, multiplexing is a method by which multiple analog or digital signals are combined into one signal over a shared medium. The aim is to share a scarce resource. For example, in telecommunications, several telephone calls may be carried using one wire. Multiplexing originated in telegraphy in the 1870s, and is now widely applied in communications. In telephony, George Owen Squier is credited with the development of telephone carrier multiplexing in 1910.
In cryptography, pseudorandom noise is a signal similar to noise which satisfies one or more of the standard tests for statistical randomness. Although it seems to lack any definite pattern, pseudorandom noise consists of a deterministic sequence of pulses that will repeat itself after its period.
In telecommunication and radio communication, spread-spectrum techniques are methods by which a signal generated with a particular bandwidth is deliberately spread in the frequency domain, resulting in a signal with a wider bandwidth. These techniques are used for a variety of reasons, including the establishment of secure communications, increasing resistance to natural interference, noise and jamming, to prevent detection, and to limit power flux density.
In telecommunications, frequency-division multiplexing (FDM) is a technique by which the total bandwidth available in a communication medium is divided into a series of non-overlapping frequency bands, each of which is used to carry a separate signal. This allows a single transmission medium such as a cable or optical fiber to be shared by multiple independent signals. Another use is to carry separate serial bits or segments of a higher rate signal in parallel.
In telecommunications and computer networks, a channel access method or multiple access method allows more than two terminals connected to the same transmission medium to transmit over it and to share its capacity. Examples of shared physical media are wireless networks, bus networks, ring networks and point-to-point links operating in half-duplex mode.
TV DX and FM DX is the active search for distant radio or television stations received during unusual atmospheric conditions. The term DX is an old telegraphic term meaning "long distance."
The base station subsystem (BSS) is the section of a traditional cellular telephone network which is responsible for handling traffic and signaling between a mobile phone and the network switching subsystem. The BSS carries out transcoding of speech channels, allocation of radio channels to mobile phones, paging, transmission and reception over the air interface and many other tasks related to the radio network.
HAVE QUICK is a ECM resistant / frequency-hopping system used to protect military Aeronautical mobile (OR) radio traffic.
The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters.
A mobile allocation index offset (MAIO) refers a time delay separating traffic channels. When a GSM mobile phone is served by a cell that is hopping over a set of frequencies, the separate traffic channels hop over the allocated frequencies according to a hopping sequence number (HSN). The traffic channels with the same HSN hop over the same frequencies in the same order but are separated in time by a mobile allocation index offset (MAIO).
MOTO Talk is a feature on some Motorola iDEN cellular phone handsets which allows users to make short-range 'push-to-talk' calls to other such handsets without being on the iDEN network. This feature goes by different names on iDEN service providers. In the US, Nextel called it 'DirectTalk' and included it as a free service on most new models of Motorola handsets. Boost Mobile disabled the function via handset software settings. SouthernLINC calls it LINCaround and ships handsets with the feature disabled. It can be enabled after paying an activation fee of $20. In Canada, TELUS calls it "Mike's Talk-Around."
KORL-FM is an American commercial radio station located in Waianae, Hawaii, broadcasting to the Honolulu, Hawaii area on 101.1 FM. KORL-FM airs an oldies music format. The station is currently owned by Hochman Hawaii Three, Inc.. It also transmits on Oceanic Time Warner Cable digital channel 883 for the entire state of Hawaii. Its studios are located in Downtown Honolulu, and its transmitter is located near Akupu, Hawaii.
Microwave transmission is the transmission of information by microwave radio waves. Although an experimental 40-mile (64 km) microwave telecommunication link across the English Channel was demonstrated in 1931, the development of radar in World War II provided the technology for practical exploitation of microwave communication. In the 1950s, large transcontinental microwave relay networks, consisting of chains of repeater stations linked by line-of-sight beams of microwaves were built in Europe and America to relay long distance telephone traffic and television programs between cities. Communication satellites which transferred data between ground stations by microwaves took over much long distance traffic in the 1960s. In recent years, there has been an explosive increase in use of the microwave spectrum by new telecommunication technologies such as wireless networks, and direct-broadcast satellites which broadcast television and radio directly into consumers' homes.
KLQB is a regional Mexican radio station serving the Austin, Texas, area. The Univision Radio outlet broadcasts at 104.3 MHz with an ERP of 48,000 watts and is licensed to Taylor, Texas. Its transmitter is located in Coupland, Texas, and the station has studios along MoPac Expressway in Northwest Austin.
WVKF is a radio station broadcasting a contemporary hit radio format. Licensed to Shadyside, Ohio, United States, the station serves the Wheeling, West Virginia, area. The station is owned by iHeartMedia, Inc..
K242CE, branded as "Throwback 96.3", is a classic hip hop radio station translator, simulcasting 99.5 WRNO-FM HD-2 licensed to Meraux, Louisiana.
