PHYSICAL-LAYER-BSIT2A-AI_Group2.pptx

BSIT 2A_AI PHYSICA LAYER L GROUP 2 PRESENTATION WHAT IS PHYSICAL LAYER? The physical layer is the lowest layer of the OSI model, responsible for the physical connection between devices. It's essentially the hardware foundation upon which all other network layers are built. KEY FUNCTION: Ph...

BSIT 2A_AI PHYSICA LAYER L GROUP 2 PRESENTATION WHAT IS PHYSICAL LAYER? The physical layer is the lowest layer of the OSI model, responsible for the physical connection between devices. It's essentially the hardware foundation upon which all other network layers are built. KEY FUNCTION: Physical Connection: Establishes and terminates the physical connection between devices using cables, connectors, and signaling mechanisms. Data Transmission: Handles the raw transmission of data bits over a physical medium like copper wire, fiber optic cable, or wireless signals. Data Encoding: Converts data into a format suitable for transmission, determining how 0s and 1s are represented in the signal. Synchronization: Ensures that devices agree on timing and data rates for communication. Media Access Control: Manages access to the physical medium when multiple devices share it.  PHYSICAL LAYER SIGNAL CONCEPT A signal is any form of information that can be transmitted or received. It's a carrier of data that varies over time or space. Representation: Signals can represent physical quantities (like temperature, sound, light) or abstract concepts (like data, information). Transmission: They are used to convey information from one point to another. Processing: Signals can be manipulated, analyzed, and modified for various purposes. Types of Signals 1.Analog Signals: Continuously varying waveforms that represent information. Examples: sound waves, light waves, voltage from a microphone. 2. Digital Signals: Discrete values representing information, typically 0s and 1s. Examples: computer data, digital images, MP3 files. 3. Communication: Radio, television, mobile phones, internet. 4. Electronics: Computers, sensors, control systems. SIGNAL PHYSICAL LAYER CONCEPT IMPAIRMENT Refers to any factor that degrades the quality of data transmission over the communication medium. Think of it like a game of telephone, where the message gets distorted as it's passed along. Here are some common types of signal impairments that can mess up communication on the physical layer: (1) Noise: Noise is like unwanted background chatter that interferes with the main conversation. It can be caused by various sources like electrical interference, radio signals, and crosstalk from neighboring cables. (2) Attenuation: Attenuation is like your voice getting quieter as you move further away from someone. It's the loss of signal strength as data travels through the communication medium, leading to signal distortion  PHYSICAL LAYER SIGNAL CONCEPT IMPAIRMENT Here are some common types of signal impairments that can mess up communication on the physical layer: (3) Distortion: Distortion is when the transmitted signal gets all muffled and unclear, like listening to a garbled voice on a bad phone line. It can happen due to signal reflections and other factors in the transmission medium. (4) Interference: Interference is like a loud interruption that disrupts the conversation. It can be caused by external sources like electronic devices, power lines, or environmental factors, leading to data errors and degraded signal quality. SIGNAL PHYSICAL LAYER CONCEPT IMPAIRMENT Here are some common types of signal impairments that can mess up communication on the physical layer: (5) Dispersion: Dispersion is like people arriving late to a meeting, causing confusion and delays. It spreads the signal over time, leading to interference and signal distortion. (6) Impulse Noise: Impulse noise is like a sudden loud noise that startles everyone in the room. It consists of short bursts of interference that can disrupt data transmission and cause errors in the received signal.  PHYSICAL LAYER CONCEPT DIGITAL TRANSMISSION The process of converting information (like text, images, or audio) into digital format (0s and 1s) and sending it over a communication channel. This method has become the backbone of modern communication due to its numerous advantages over analog transmission. Key Concepts Digitization: Converting analog signals (like sound waves or light) into digital format. Encoding: Representing digital data as electrical signals for transmission. Modulation: Combining digital data with a carrier signal for transmission over analog channels. Demodulation: Extracting digital data from the carrier signal at the receiver. Error Detection and Correction: Ensuring data integrity during transmission.  PHYSICAL LAYER DIGITAL CONCEPT TRANSMISSION Applications Digital transmission is used in a wide range of applications, including: Telecommunications: Internet, telephone, mobile networks Broadcasting: Digital TV, radio Data Storage: Hard drives, SSDs, CDs, DVDs Networking: LANs, WANs Common Digital Transmission Techniques Pulse Code Modulation (PCM): Analog-to-digital conversion for voice signals. Time Division Multiplexing (TDM): Combining multiple digital signals into a single channel. Frequency Division Multiplexing (FDM): Combining multiple analog signals into a single channel. Asynchronous and Synchronous Transmission: Different methods of data  PHYSICAL LAYER CONCEPT DIGITAL TRANSMISSION Challenges Despite its advantages, digital transmission faces challenges such as: Bandwidth Limitations: Capacity constraints for high- speed data transfer. Security Threats: Vulnerability to hacking and data breaches. Interference: Noise and distortion can affect signal quality.  PHYSICAL LAYER ANALOG CONCEPT TRANSMISSION a method of conveying information using a continuous signal that varies in amplitude, phase, or some other property in proportion to the information being transmitted. In simpler terms, it's like sending a wave that mirrors the original information, such as sound or video. How does it works? Continuous: The signal varies smoothly over time, without discrete steps. Susceptible to Noise: Analog signals are easily affected by noise, which can degrade the quality of the transmitted information. Wide Bandwidth: Typically requires a wider bandwidth compared to digital signals for the same data rate  PHYSICAL LAYER ANALOG CONCEPT TRANSMISSION  PHYSICAL LAYER ANALOG CONCEPT TRANSMISSION Modulation Techniques To transmit data using analog signals, modulation techniques are employed. These techniques involve combining the information signal with a carrier wave. Amplitude Modulation (AM): The amplitude (height) of the carrier wave is varied to represent the information. Frequency Modulation (FM): The frequency (number of cycles per second) of the carrier wave is varied to represent the information. Phase Modulation (PM): The phase (starting point) of the carrier wave is varied to represent the information.  PHYSICAL LAYER ANALOG CONCEPT TRANSMISSION Advantages: Advantages and Disadvantages 1. Relatively simple to implement. 2. Well-suited for analog signals like voice and video. Disadvantages: 1. Susceptible to noise and interference. 2. Lower data rate compared to digital transmission. 3. Difficult to amplify without introducing noise.  PHYSICAL LAYER MULTIPLEXI CONCEPT NG A technique that allows a number of lower bandwidth communication channels to be combined and transmitted simultaneously over one higher bandwidth channel. At the receiving end, demultiplexing recovers the original lower bandwidth channels. The main purpose of multiplexing is to make efficient use of the full bandwidth of a communication channel and achieve a lower per channel cost. The three basic multiplexing methods in use are space- division multiplexing, frequency-division multiplexing, and time-division multiplexing. DATA TRANSMISSION PHYSICAL LAYER CONCEPT The transfer of data from one digital device to another. This transfer occurs via point-to-point data streams or channels. These channels may previously have been in the form of copper wires but are now much more likely to be part of a wireless network. Types of Data Transmission Data may be transmitted between two points in two different ways. (1) Serial Transmission Serial data transfer refers to transmitting data one bit at a time. The objective of serial data transmission is to send the bytes from one point to another along a single line or channel. That is, the bits representing a given character are sent serially, one at a time. (2) Parallel transmission In parallel transmission, as the name implies, the bits of a character are sent in parallel (simultaneously) using as many signal carrying lines as there are bits. For example, to transfer an eight-bit character from one subsystem to another, eight separate signal DATA TRANSMISSION PHYSICAL LAYER CONCEPT Data Transmission Techniques There are two main methods of sending/ transmitting data, Synchronous and Asynchronous transmission. 1. Synchronous Refers to events that are synchronized or coordinated in time. For example, if the interval between transmitting characters A and B is the same as that between B and C, it is synchronous transmission. Also completing the current operation before the next one is started is considered synchronous operation. 2. Asynchronous Refers to events that are not synchronized, or coordinated, in time. It is the opposite of synchronous. Most communication between computers and devices is asynchronous – it can occur at any time and at irregular intervals. DATA TRANSMISSION PHYSICAL LAYER CONCEPT The following are considered asynchronous operations: The interval between transmitting characters A and B is not the same as between transmitting characters B and C. The ability to initiate a transmission at either end. The ability to store and forward messages. Starting the next operation before the current one is completed.  Summary Physical Layer lowest layer of OSI Signals carry information Signal Impairment degrades signal quality Digital Transmission uses discrete signals for data transmission Analog Transmission uses continuous signals Data is the raw material of information Transmission is the process of sending data Multiplexing combines multiple data streams into one