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| Coaxial un-balanced type of Transmission Line Cable |
Transmission
Basic transmission in Telecommunication Networks means the transfer of data or information from one place to another. It is done through various technical methods and protocols. Basically, telecommunication networks involves a few key components and principles for transmission.
- source
It is the location or device from which the transmission of data or information originates. For example, a computer, mobile phone, or telephone.
- Computer
It is used to send emails, web pages, and files.
- Mobile Phone
For calls, SMS, and internet data.
- Sensors
To send various data such as temperature or pressure information.
2.Transmitter (sender)
This device or circuit converts the data into a signal, so that it can be transmitted
3. Transmission medium
A path or medium through which signals can be transmitted from one place to another. Such mediums can be both wired (best examples are fiber optic cables or coaxial cables) and wireless systems (such as radio waves or satellite links).
- Wired Medium
- Twisted pair cables
It is used in telephone networks and LANs. Stands for Local Area Networking.
- Coaxial cables
This type of cable is commonly used for Television 📺 and Internet connections.
- Fiber optic cables
This type of cable has high-bandwidth and it is used to long-distance communications system.
- Wireless Medium
- Radio waves
It is used in mobile networks, Wi-Fi, and broadcasting.
- Microwaves
For satellite communications and dedicated links.
- Infrared
Short-range communications, such as remote control.
4. Receiver
This device or circuit receives signals and converts them back into data. For example, a modem or radio receiver.
5. Destination.
It is the location where data or information is received and used, such as a computer, mobile phone, or telephone.
Types of signaling
There are two basic types of signaling used in telecommunication which are as follows.
Analog Signaling
These signals are continuous and transmit information in the form of a wave. For example, radio waves and old telephone signals.
Continuous signals
They are transmitted without interruption.
Amplitude Modulation (AM)
Frequency Modulation (FM)
Digital Signaling
These signals are discontinuous and transmit information in the form of binary code (0s and 1s). For example, Internet data and mobile network signals are included.
Discrete signals
Pulse Code Modulation (PCM)
Digital modulation schemes Amplitude Shift Keying (ASK)
It Changes the amplitude of a signal based on binary data.
Phase Shift Keying (PSK)
Phase shifting in telecommunications refers to changing the phase of a signal in order to transmit information through it. In these communication systems, phase shift keying (PSK) is a common technique used to modulate digital signals.
Phase shift keying (PSK) is a modulation scheme in which digital data is transmitted by changing the phase of an analog carrier signal. There are different types of PSK, such as the following types
BPSK (Binary Phase Shift Keying)
It uses two phases, 0 degrees and 180 degrees. Each binary bit (0 or 1) is transmitted at a specific phase. 0 degrees for the 0 bit and 180 degrees for the 1 bit.
QPSK (Quadrature Phase Shift Keying) It uses four phases.
Such as 0, 90, 180, and 270 degrees. Each two bits (group of two bits) is transmitted at a specific phase. This provides the ability to transmit more data.
8-PSK
It uses eight phases, allowing three bits to be transmitted per symbol. This provides even more data transfer capacity, but also increases complexity and sensitivity to noise.
Description of Phase Shifting
Phase In shifting, the phase of the signal is changed according to the specified binary data. These changes occur at the beginning of the signal wave. For example: If a binary “0” is to be transmitted, the phase of the signal is set to 0 degrees. If a binary “1” is to be transmitted, the phase of the signal is set to 180 degrees. (in BPSK).
Quadrature Amplitude Modulation (QAM)
Amplitude and phase. Transmits data by converting both.
Protocols and standards
Various protocols and standards are used during transmission to ensure that data is transmitted accurately and without loss. Some popular protocols and standards are included.
TCP/IP
The basic protocol used for the transmission of data over the Internet.
HTTP/HTTPS
This type of protocol used for web pages and web services.
File Transfer Protocol
A file transfer protocol, used to transfer files from one computer to another.
Error Control and Flow Control
Error control and flow control mechanisms are used to avoid any type of error during transmission.
Error Control
These mechanisms correct errors that occur during data transmission. For example, checksum and CRC.
Flow control
These mechanisms ensure that the transmission speed between the sender and receiver of data is balanced. These basic transmission principles and components work together in telecommunication. So that effective and efficient transfer of information is possible.
Transmission by lines
Main Type Of Transmission Lines.
The simplest agreement of transmitting electric power between any two points on earth is connecting them by an insulated conductor and using earth as return path, such a system will fairly work for carrying DC or low frequency AC power. A single iron wire and earth return circuit was extensively used for transmission of telephrap signals (DC pulses) in past.
The associated electromagnetic field (along and around the conductor) cause radiation of power with increase of frequency. The open wire line is also exposed to electromagnetic induction from the neighboring AC power lines. The single conductor earth return transmission system was not suitable for telephony where the speech frequencies were to be transmitted and the interference caused by the induction along the transmission path was under undesirable.
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| Transmission Lines |
A better agreement was to use two insulated conductors for speed transmission. As current in the two conductors was equal and opposite in direction the resultant electromagnetic field along the path was reduced. The net induction from outside sources was also diminished. Similar distance between the conductors result in more effective cancellation of the electromagnetic field.
The actual distance is, however, determined by practical considerations. In case of open wire line supported by insulators on poles, the distance between the wire depends on the expected swing of wires (erected with a specific tension) with the wind.
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| Coaxial cable consists of inner conductor at center of outer tubular conductor |
A concentric conductor transmission lines comprises a central conductor and a circular conducting tube. The two conductors are separated by dielectric medium. The electromagnetic field is mainly confined in the space between the conductors and there is minimum radiation, The induction from external sources is mostly eliminated. This is called coaxial line.
The type of line with two conductors at equal height is called balanced line. The single conductor earth return or the coaxial line is called un-balanced line.
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| Coaxial (un-balanced) Line |
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| Parallel-wire (balanced) Line |
Cross Talk Between Transmission Lines
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| Cross Talk |
Transportation
In case of two balanced open wire lines, this crosstalk can be minimized by changing position of wires for half the length on one of the lines. The equal exposure to the two wires of the other line is thus achieved. This method is called transportation. For large number of pairs on one alignment of poles, complex transportation schemes are adopted.
