Untitled Flashcards Set

Physical Layer

The first layer in the Internet model, responsible for the transmission of raw data over physical circuits.

Point-to-Point Circuit

A direct connection between two devices.

Multipoint Circuit

A shared connection among multiple devices.

Simplex

One-way communication.

Half-Duplex

Two-way communication, but only one direction at a time.

Full-Duplex

Simultaneous two-way communication.

Serial Transmission

Bits sent one at a time.

Parallel Transmission

Multiple bits sent simultaneously.

Multiplexing (MUX)

The process of combining multiple low-speed circuits into one high-speed circuit.

TDM (Time-Division Multiplexing)

Divides transmission into time slots.

FDM (Frequency-Division Multiplexing)

Uses different frequency bands for transmission.

WDM (Wavelength-Division Multiplexing)

Uses different light wavelengths in fiber optics.

Guided Media

Wired transmission methods such as twisted-pair, coaxial, and fiber-optic cables.

Twisted-Pair Cable

Used in local area networks (LANs), cost-effective.

Coaxial Cable

Used in cable television, offers better shielding.

Fiber-Optic Cable

Allows high-speed data transmission over long distances.

Digital Transmission

Uses discrete binary signals (0s and 1s) for data transmission.

Analog Transmission

Uses continuous waves for data transmission.

AM (Amplitude Modulation)

A modulation technique that varies the height of the wave.

FM (Frequency Modulation)

A technique that varies the number of waves per second.

PM (Phase Modulation)

A technique that varies the starting point of the wave.

Pulse-Code Modulation (PCM)

Techniques for converting analog signals into digital signals by sampling and quantizing.

Quantizing Error

The difference between the original analog signal and its digital approximation.

Data Rate Calculation

Data Rate = Symbol Rate × Bits per Symbol.

64-QAM

A modulation scheme using 6 bits per symbol.

256-QAM

A scheme using 8 bits per symbol for higher data rates.