Editing Communications system (section)

== Key components ==
===<span lang="ms" dir="ltr">Sources</span>===
Sources can be classified as '''electric''' or '''non-electric'''; they are the origins of a message or input signal.  Examples of sources include but are not limited to the following:
* [[Audio files]] (MP3, WAV, etc...)
* [[GIF|Graphic Image Files]] (GIFs)
* [[Email|Email Messages]]
* [[Human voice]]
* [[Cathode-ray tube|Television Picture]]
* [[Electromagnetic radiation]]

=== Input transducers (sensors) ===
Sensors, like microphones and cameras, capture non-electric sources, like sound and light (respectively), and convert them into electrical signals. These types of sensors are called '''input transducers''' in modern analog and digital communication systems. Without input transducers there would not be an effective way to transport non-electric sources or signals over great distances, i.e. humans would have to rely solely on our eyes and ears to see and hear things despite the distances.

Other examples of input transducers include:
* [[Microphone]]s
* [[Camera]]s
* [[Computer Keyboard|Keyboards]]
* [[Computer mouse|Mouse]]
* Force sensors
* [[Accelerometer]]s

=== Transmitter ===
Once the source signal has been converted into an electric signal, the transmitter will modify this signal for efficient transmission. In order to do this, the signal must pass through an electronic circuit containing the following components:
# [[Noise filter]]
# [[Analog-to-digital converter]]
# Encoder
# [[Modulation|Modulator]]
# [[Signal amplifier]]
After the signal has been amplified, it is ready for transmission.  At the end of the circuit is an antenna, the point at which the signal is released as electromagnetic waves (or electromagnetic radiation).

=== Communication channel ===
A communication channel is simply referring to the medium by which a signal travels.  There are two types of media by which electrical signals travel, i.e. '''guided''' and '''unguided'''. Guided media refers to any medium that can be directed from transmitter to receiver by means of connecting cables.  In optical fiber communication, the medium is an optical (glass-like) fiber.  Other guided media might include coaxial cables, telephone wire, twisted-pairs, etc... The other type of media, unguided media, refers to any communication channel that creates space between the transmitter and receiver.  For radio or RF communication, the medium is air.  Air is the only thing between the transmitter and receiver for RF communication while in other cases, like sonar, the medium is usually water because sound waves travel efficiently through certain liquid media. Both types of media are considered unguided because there are no connecting cables between the transmitter and receiver.  Communication channels include almost everything from the vacuum of space to solid pieces of metal; however, some mediums are preferred more than others.  That is because differing sources travel through subjective mediums with fluctuating efficiencies.

=== Receiver ===
Once the signal has passed through the communication channel, it must be effectively captured by a receiver.  The goal of the receiver is to capture and reconstruct the signal before it passed through the transmitter (i.e. the A/D converter, modulator and encoder).  This is done by passing the "received" signal through another circuit containing the following components:
# Noise Filter
# [[Digital-to-analog converter]]
# Decoder
# Demodulator
# Signal Amplifier
Most likely the signal will have lost some of its energy after having passed through the communication channel or medium. The signal can be boosted by passing it through a signal amplifier. When the analog signal converted into digital signal.

=== Output transducer ===
The output transducer simply converts the electric signal (created by the input transducer) back into its original form.  Examples of output transducers include but are not limited to the following:
* Speakers (Audio)
* Monitors (See Computer Peripherals)
* Motors (Movement)
* Lighting (Visual)

=== Other ===
Some common pairs of input and output transducers include:
# Microphones and speakers (audio signals)
# Keyboards and computer monitors
# Cameras and liquid crystal displays (LCDs)
# Force sensors (buttons) and lights or motors

Again, input transducers convert non-electric signals like voice into electric signals that can be transmitted over great distances very quickly. Output transducers convert the electric signal back into sound or picture, etc...  There are many different types of transducers and the combinations are limitless.