Communication is the transmission of information between people. It can be written, visual, or verbal.
A transmitter at one location and a receiver at another are connected by a channel. This channel transmits the message signal between them.
Sensors like microphones and cameras capture non-electric sources and convert them into electrical signals. Transducers are used in modern communication systems to transmit these signals.
1. Wireless
Communication systems that transfer information without the use of electrical wires are called wireless. They include cellular phones, Bluetooth, Wi-Fi, Satellite communications, etc. The three essential elements in any communication system are the transmitter, medium or channel, and receiver.
The transmitter converts the message signal into electromagnetic waves that are then transferred by the channel. The channel may be a copper wire, cable, optical fiber, or radio waves. The receiver then decodes these signals to retrieve the original information.
When the original message signals can’t be transmitted over large distances, they are superimposed with high-frequency and amplitude waves called carrier signals. This process is called modulation, and the result is a signal that can be transmitted over long distances. A repeater extends the range of a communication system by amplifying these signals. Any electrical signals that interfere with the message signals are known as noise.
Among the most popular wireless communication systems are mobile phone networks. Cellular communications work by bouncing radio waves off cell towers and directing them to call receivers using triangulation. The system also uses a database to identify each user’s location and assign them a unique cell phone number.
Another common type of wireless communication system is paging, which transfers messages to pagers over short-range low-energy radio waves. These devices are used for voice, text, and data transmission. Paging is a simple communication system, meaning that it only sends one message at a time.
Bluetooth is a short-range wireless communication system that allows users to connect their smartphones, computers, and other electronics to each other. It transmits data, audio, and video signals over short-range radio waves that can pass through walls and other obstacles. The technology also includes a central network that broadcasts service set identifier beacons to endpoint devices.
2. Radio
A radio communication system sends signals from one transmitter to another using electromagnetic waves. The transmitter processes the signal through various stages like signal representation, shaping, encoding, and modulation. It then passes through the transmission medium like copper wire or air. When the signal reaches the receiver, it is decoded and used by the end user.
The transmission medium can affect the quality of a signal or even cause it to fail. This happens because of interference or noise, which causes the signal to be corrupted or lost. The signal is also subject to attenuation, which decreases the amplitude or strength of a signal.
In the case of a radio, the signal is transmitted using electromagnetic waves that are reflected or amplified by objects. This is why it is difficult to use a radio in an environment with a lot of background noise or if you are too close to another person.
While there are many different kinds of radio systems, the two main types are conventional and trunked. Conventional radios allow users to select the channel they want to transmit on, assuming that no other user is using it. On the other hand, a trunked radio system manages those channels by a central network, which automatically assigns users to available transmission paths (or “trunks”) based on their location or group.
The idea behind radio was first proposed by James Clerk Maxwell in the early 1860s, and Heinrich Hertz showed that electromagnetic waves existed in 1886. However, Italian inventor Guglielmo Marconi took the concept and developed it into a wireless telegraph system for sending Morse Code messages between two points more than a kilometer away in 1895. This eventually led to two-way radio communications, including walkie-talkies and mobile phones.
3. Optical
An optical communication system uses light as a carrier signal to carry information from one place to another. It consists of a transmitter that encodes a message into an optical signal, a communications channel that carries the optical signal to its destination, and a receiver that reproduces the original message from the received optical signal.
The message carries information in the form of a single-valued function of time, such as audio, video, temperature, picture, pressure, or any other physical variable. These variations are converted to electrical signals using a transducer that converts physical variables (e.g., pressure, force, temperature) to corresponding changes in electrical signal variations. The signal variations are then transmitted to a remote receiver over long distances by optical fiber with photodiode and VCSEL components, where the optical signal is modulated into a data stream for transmission.
Unlike fixed wireless systems, optical communication is immune to electromagnetic interference and can be used over very long distances without losing energy. In addition, it can be routed around obstacles to overcome obstacles like buildings, where the speed of light is reduced due to reflection. For very high-speed transmission, silica fibers are often used, but for shorter distances, plastic optical fiber can also be advantageous.
Optical communication can be found in a wide range of applications, including data centers that need to transfer massive volumes of information between servers and switches. It can also be used for HD cable television, streaming video services, telemedicine, and remote work. It is typically much faster than wireless transmission, although this depends on the cable length and signal modulation. For example, a high-speed data link with 1.3 mm silica optical fiber can achieve speeds up to 25 Gbps, but more advanced modulation techniques are needed with higher data rates.
4. Fiber-optic
In optical communications, data is transmitted by pulses of light. This technology has revolutionized the telecommunications industry and is used to provide high-speed data and broadband services to consumers. It also provides a much clearer signal than electrical signals can, which is especially important over long distances. These systems are capable of sending data over tens of miles with very little signal loss. They are also immune to electromagnetic interference (EMI) that can compromise standard electrical signals.
Optical communication uses thin strands of glass fiber that are coated with light-sensitive materials to carry digital information. The data is encoded into a series of light pulses that travel along the fiber at the speed of light (186,000 miles per second) to their destination. When they arrive, the pulses are decoded back into the original data. This information can then be transformed into a picture, audio sound, or written information that we can understand.
This type of communication system can handle a huge amount of data and is much faster than copper cables. It is also immune to electromagnetic interference, which can affect copper cables. In addition, fiber optics are more flexible than electrical wires and can be bent without losing their signal.
Fiber-optic communication systems are commonly found in business office buildings, and they serve as the backbone of many cellular communications networks. They are also being used to connect mobile phone base stations and will probably be a key component in the next generation of wireless technology, 5G. These systems are also becoming increasingly popular in industrial settings because of their lightning-fast data transmission capabilities and lower latency. This allows for real-time data transmission and faster decision-making processes.
5. Satellite
As the name implies, satellite communications use a satellite to relay radio telecommunication signals between two points on Earth. These signals are first beamed to the satellite by the transmitter on the ground, then down again to the receiver at another point on Earth. In the end, the satellite will send the signal to a terrestrial antenna that will then pass it along to your cellphone or other device.
The difference between this and other communication systems is that instead of sending and receiving data through the air or sea, a satellite uses a free-space communication channel to communicate between two points. At the top level, a satellite transmission system uses a modulator to encode digital information into an analog electromagnetic wave. Then a power amplifier increases the RF output power of that wave to send it up into the atmosphere and into space, where it will travel to its destination on the other side of the world.
While terrestrial communication channels have a number of limitations, satellites can provide high-speed data and voice communications over long distances without the need for wires. This is because of the ability of satellites to use different orbital paths to maximize coverage and signal strength, depending on the application.
However, a satellite is still located thousands of miles above the surface of the Earth and requires line-of-sight with its receiver. This means that weather and other obstructions can seriously affect the quality of satellite transmissions. In addition, satellites experience a delay known as propagation delay that can cause seemingly unnatural pauses in communication. These differences can make it difficult to compare a satellite communication system to cellular or two-way radio systems.
