Physical Layer Issues Flashcards
What are the types of transmission environments?
The types of transmission environments are copper (used in traditional electric networks), fiber (used in high-speed optical networks), and air (used for wireless transmission).
What are the types of transmission media?
Types of transmission media include electromagnetic waves (air and some wired), radio waves (long-distance communication), microwaves (satellite communication), infrared and laser light (short-range transmission), and electric charge (wired networks).
What is the primary medium for electric networks?
Copper wires are the primary medium for electric networks due to their conductivity and cost efficiency. Alternatives include aluminum, platinum, and gold.
How is data transmitted in electric networks?
Data is transmitted through variations in electrical charge (voltage) via network cables.
What is electromagnetic interference, and how is it mitigated?
Electromagnetic interference occurs when conductive materials generate fields that affect signals. Mitigation techniques include shielding cables and twisting wires within cables to reduce cross-talk.
What are coaxial cables and their uses?
Coaxial cables are used in cable TV, older Ethernet standards, and token bus networks. They consist of a central conductor, insulating layer, metal shield, and outer jacket.
What are Unshielded Twisted Pair (UTP) cables?
UTP cables are common in Ethernet and telephone networks, made of twisted pairs of copper wires to minimize interference.
What is airwave transmission?
Airwave transmission uses radio or microwaves to transmit data, often assisted by satellites to extend communication range.
What is optical transmission?
Optical transmission uses light waves (laser or LED) to transmit data through glass fibers, with reflective and refractive optical cables guiding light efficiently or bending light around corners.
What is reflection in transmission physics?
Reflection occurs when light bounces off a surface, with the angle of incidence equal to the angle of reflection.
What is refraction in transmission physics?
Refraction occurs when light bends as it enters a material with a different density, altering its angle.
What is the purpose of carrier waves?
Carrier waves transmit data by modulating a sinusoidal waveform, representing binary data through modulation techniques.
What are the types of modulation?
Types of modulation include:
Amplitude Modulation (AM): Varies wave amplitude to represent 0s and 1s.
Frequency Modulation (FM): Varies wave frequency to represent data.
Phase Shift Modulation (PSM): Shifts the wave’s temporal position to encode data.
What is the function of a modem?
A modem modulates digital data into carrier wave variations and demodulates modulated waves to extract the digital data.
What are the types of modems?
Types of modems include standard telephone modems (using analog signals) and DSL modems (using unused audio frequency bands for high-speed transmission).
What is Frequency Division Multiplexing (FDM)?
FDM splits a broadband medium into narrowband channels to allow simultaneous transmissions.
What is Time Division Multiplexing (TDM)?
TDM assigns time slices to each signal, enabling sequential transmission over the same medium.
How is multiplexing applied in cable modems?
Cable modems use coaxial cables and TDM for digital data transmission, with separate channels for upstream and downstream communication.
What is the difference between multiplexing and demultiplexing?
Multiplexing combines multiple signals into a single complex signal, while demultiplexing restores individual signals from the complex signal.
