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In Cellular Radio, AMPS stand for

Advanced Mobile Phone Service

In Cellular Radio, BSC stands for

Base Station Controller

In Cellular Radio, MSC stands for

Mobile Switching Center

In GSM, voice channels are called

traffic channels

In Mobile Communications, GSM uses

frequency hopping

In Mobile Communications, IMSI stands for

International Mobile Subscriber Identification

An acoustical phenomenon wherein the sound continues to persist after the cause of sound has stopped resulting in repeated reflections is called

Reverberation

A type of microphone that uses the principle of a capacitor as a means of transduction. It uses a polarizing voltage of between 9 and 48 V of DC supply applied to its diaphragm by an external power supply

Condenser

A number from 0 to 1 representing the ability of a surface material to absorb sound energy is known as

Absorption Coefficient

The difference in dB between the loudest level of sound and the softest passage of sound is known as

dynamic range

The highest frequency that can be used for skywave propagation between two specific points on earth’s surface

Critical Frequency

Variation in signal loss caused by natural weather disturbances

Fading

The height above the earth’s surface from which a refracted wave appears to have been reflected

virtual height

The highest frequency that can be used for skywave propagation between two specific points on earth’s surface

Critical Frequency

Electromagnetic waves that are directed above the horizon level

sky waves

The angular separation between the two half-power points on the power density radiation pattern

Beamwidth

Refers to the direction in space of electric vector of the electromagnetic wave radiated from an antenna and is parallel to the antenna itself

Polarization

Placing a metallic array on the antenna effects to increase the current at the base of the antenna, and also to make the current distribution more uniform. What is this called

Top loading

What principle that states that the properties of an antenna are independent of whether it is used for transmission or reception

Principle of reciprocity

This is often used to cure the problem of great thickness required of lenses used at

Zoning

lower microwave frequencies or for strong curved wavefronts A structure-generally metallic and sometimes very complex-designed to provide an efficient coupling between space and the output of a transmitter or input to a receiver

antenna

The ratio comparing the power density generated by a practical antenna in some direction, with that due to an isotopic antenna radiating the same total power

Directive gain

Any array that is directional at right angles to the plane of the array is said, by inference, to have

Broadside action

The ratio of the focal length to the mouth diameter is called __ of the parabola, just as in camera lenses

Aperture

Corresponds to a resonant transmission line, and the dipole antennas describe so far have been resonant

Resonant antenna

The location of an earth station is generally specified in terms of

azimuth and elevation

Determines each digit of the PCM code sequentially

digit at a time

Logic circuits sense the highest threshold circuit sensed by the PAM input signal and produce the approximate PCM code

word at a time