An invisible force field created by a magnet,

Generated around a conductor when current flows through it.

Also an invisible force field produced by the presence of a potential difference between two conductors.

Antenna acts as the interface between a transmitter or receiver and free space.

Radiates or senses an electromagnetic field.

Describes the region directly around the antenna where the electric and magnetic fields are distinct,

These fields are not radio wave, but they do contain any information transmitted.

Approximately 10 wavelengths from the antenna is the radio wave with the composite electric and magnetic fields,

Its strength also diminishes with distance but only at the square of the distance.

Means that the characteristics and performance of an antenna are the same whether the antenna is radiating or intercepting an electromagnetic signal.

The angular separation between the two half-power (-3 dB) points on the major lobe of an antenna’s plane radiation pattern, usually taken in one of the “principal” planes.

Antenna bandwidth is often expressed as a percentage of the antenna’s optimum frequency of operation.

Refers to the orientation of magnetic and electric fields with respect to the earth.

Antenna Types: One of the most widely used antenna types is the half-wave dipole,

Also formally known as the Hertz antenna.

Antenna Type: is commonly used at frequencies up to 2 MHz (such as standard AM broadcast), also used as a whip antenna for mobile applications (police, taxi) because of its simplicity and omnidirectional pattern.

Antenna Types: Widely used antenna that commonly uses a folded dipole as the driven element.

Antenna Types: Provides extremely high gain and directivity and are very popular for microwave radio and satellite communication links.

All metallic objects reflect radio waves, especially if the metallic object is at least one-half wavelength at the frequency of operation.

is the bending of a wave due to the physical makeup of the medium through which the wave passes

If an obstacle appears between a transmitter and receiver, some of the signal is blocked, creating what is known as a shadow zone.

Pulse Modulation: The process of changing a binary pulse signal to represent the information to be transmitted.

Simplest form of pulse modulation,

Sampled at regular intervals, and each sample is made proportional to the amplitude of the signal at the instant of sampling

Fixed amplitude and starting time of each pulse,

Width of each pulse is made proportional to the amplitude of the signal at that instant

The most widely used technique for digitizing information signals for electronic data transmission,

Only digitally encoded modulation technique that is commonly used for digital transmission.

Pulse Code Modulation: The most widely used technique for digitizing information signals for electronic data transmission