A robocall is a phone call that is made using a computerized autodialer to deliver a pre-recorded message, as opposed to a live person. Robocalls are commonly used for telemarketing or political campaigning, but they can also be used for other purposes, such as delivering weather or emergency alerts. Robocalls are generally considered to be … Read more

Internet caller ID

Internet caller ID is a service that allows a person to see the identity of the person calling them when the call is placed over the internet, rather than over a traditional phone line. This can be useful in a variety of situations, such as when someone is trying to avoid a telemarketer, or when … Read more


The fennec is a small nocturnal mammal of the desert regions of North Africa and the Arabian Peninsula. It is the smallest member of the canid family, with a head-and-body length of only 40–50 cm (16–20 in). The fennec has large ears which help it to hear prey moving underground, and long furry hind legs … Read more

Vestigial sideband (VSB)

In telecommunications, vestigial sideband (VSB) is a type of single-sideband modulation (SSB) where the bandwidth of the modulated signal is reduced by filtering out all but one of the sidebands. This is done by adding a filter to the modulation stage so that only one of the sidebands is passed to the transmitter. The other … Read more

White space device (WSD)

A white space device (WSD) is a communications device that uses the unused spectrum in the television broadcast band (the “white spaces”) for wireless communication. WSDs are similar to other unlicensed devices, such as Wi-Fi routers, that operate in the unlicensed 2.4 GHz and 5 GHz bands. However, WSDs have the potential to operate in … Read more

Message broker

A message broker is a computer program that facilitates the exchange of information between applications. Message brokers are used in a variety of applications, including telecommunications, e-commerce, web services, and event-driven architectures. In telecommunications, message brokers are used to route messages between applications and networks. Message brokers can also be used to convert messages from … Read more

Multi-carrier modulation (MCM)

MCM is a type of signal modulation where multiple carrier waves are combined to form a single signal. This signal can then be used to carry information. MCM is often used in wireless communications systems, where it can provide advantages over other modulation schemes. Which type of modulation method is used in multi carrier modulation? … Read more

Carrier network

A carrier network is a type of telecommunications network that is used to provide voice and data services to subscribers. The term carrier network can refer to either the public switched telephone network (PSTN) or the mobile phone network. The PSTN is the traditional voice telephone network that is operated by the local telephone companies. … Read more

Decibels relative to isotropic radiator (dBi)

The decibel is a unitless measure of the ratio of two values, and is often used to measure sound levels. The “i” in dBi stands for “isotropic,” meaning that the signal is emanating from a point source in all directions. An isotropic radiator is an idealized point source that emits energy equally in all directions. … Read more

United Launch Alliance (ULA)

United Launch Alliance (ULA) is a joint venture of Lockheed Martin Space and Boeing Defense, Space & Security. ULA was formed in 2006 to provide launch services for the US government. ULA launches more than half of all US government satellites, and is the provider of choice for launching classified government missions. ULA is also … Read more