What is a Carrier

Discussion

Carrier Signal

A frequency in a communications channel modulated to carry analog or digital signal information. For example, an FM radio transmitter modulates the frequency of a carrier signal and the receiver processes the carrier signal to extract the analog information. An AM radio transmitter modulates the amplitude of a carrier signal.

Carrier System

A communications system providing a number of point-to-point channels through some type of multiplexing. T-1 and T-3 carrier services are examples of carrier systems that can be used between points in a Wide Area Network (WAN).

carrier service provider:

A company offering telephone and data communications between points in a state or in one or more countries. The Regional Bell Operating Companies (RBOCs) are example of carriers.

Modulation

Technique for impressing information (voice, music, picture, or data) on a radio-frequency carrier wave by varying one or more characteristics of the wave in accordance with the intelligence signal

Modulation Types

b) Amplitude modulation (AM) b) Frequency Modulation (FM) c) Phase Modulation (PM) d) Pulse coded Modulation (PCM) e) Pulse Duration Modulation (PDM)

Amplitude Modulation (AM)

Auditory or visual information is impressed on a carrier wave by varying the amplitude of the carrier to match the fluctuations in the audio or video signal being transmitted

Frequency Modulation (FM)

The amplitude of the carrier is kept constant, but its frequency is altered in accordance with variations in the audio signal being sent.

Phase Modulation

The phase of a carrier wave is varied in response to the vibrations of the sound source in phase modulation (PM).

Pulse-coded modulation (PCM), In the intelligence signal converts

the carrier into a series of constant-amplitude pulses spaced in such a manner that the desired intelligence is contained in coded form.

Pulse-duration modulation (PDM), Another kind of pulse modulation is

in which intelligence is represented by the length and order of regularly recurring pulses.

What is a wavelength?

The distance between the peak of one wave to the next.

Adding intelligence to the waveform By modulating a waveform we can add

intelligence to the transmitted wave.

Carrier

The Carrier is the portion of the wave which carries no inteligence

the unmodulated single-frequency electromagnetic wave that carries the desired information