Page 126 - DCAP307_PLANNING_AND_MANAGING_IT_INFRASTRUCTURE

Planning and Managing IT Infrastructure

Notes 2. Broadcast Radio: Basically an audio broadcasting service, radio broadcasts sound through
the air as radio waves. It uses a transmitter to transmit radio waves to a receiving antenna.
To broadcast common programming, stations are linked to the radio networks. The
broadcast occurs either in syndication or simulcast (simultaneous broadcast) or both. Radio
broadcasting can also be done via cable FM, the internet and satellites. A radio broadcast
sends data over long distances (across countries) at up to 2 megabits per second (AM/FM
Radio).
3. Microwave Radio: Microwave transmission involves the transfer of voice and data through
the atmosphere as super high-frequency radio waves called microwaves. Microwave
transmission is mainly used to transmit messages between ground-based stations and
satellite communications systems. Microwave transmission mainly uses radio
waves whose wavelengths are conveniently measured in small units such as
centimetres. Microwaves belong to the radio spectrum ranges of roughly
1.0 gigahertz (GHz) to 30 GHz.
4. Communications Satellites: A communication satellite is an artificial satellite used
specifically as a communication transmitter/receiver in orbit. It behaves like a radio
relay station above the earth to receive, amplify, and redirect analog and digital signals
carried on a specific radio frequency.

Task Make distinction between microwave radio and broadcast radio.

Self Assessment

Fill in the blanks:

1. .................................... is the transfer of information over a distance without the use of
electrical conductors or wires.
2. .................................... involves the transfer of voice and data through the atmosphere as
super high-frequency radio waves called microwaves.
3. A .................................... is an artificial satellite used specifically as a communication
transmitter/receiver in orbit.

7.2 Cell Phone Services

Cellular systems provide two-way voice and data communication with regional, national, or
international coverage. Cellular systems were initially designed for mobile terminals inside
vehicles with antennas mounted on the vehicle roof. Today these systems have evolved to
support lightweight handheld mobile terminals operating inside and outside buildings at both
pedestrian and vehicle speeds.
The basic premise behind cellular system design is frequency reuse, which exploits the fact that
signal power falls off with distance to reuse the same frequency spectrum at spatially-separated
location.

Example: A cellular network is a mobile phone (cell phone) network.
“Mobile” wireless technologies provide voice and data communication services to mobile users
who use cell phones, PDAs, etc.

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