Data Transmission Basics

Continuous data that takes on continuous values.

Data with discrete states and discrete values.

Sending digital signals directly over the transmission medium, using the entire bandwidth.

Difference between the highest and lowest frequencies in a signal.

The amount of information encoded into a single signal level.

A composite analog signal with frequencies from zero to infinity.

A technique where multiple signals are sent simultaneously on different frequency bands of the same medium, used in broadband transmission.

The amount of space needed to send bits, directly proportional to bit rate.

Sends data on multiple frequencies simultaneously using analog signals.

Signal changes during transmission due to imperfections of medium.

Loss of signal strength (energy) during transmission.

Change in signal shape and form during transmission.

Unwanted signals disrupting the transmission.

A unit used to measure the relative strength of two signals or a signal at two different points.

The ratio of the desired signal power to the unwanted noise power. It indicates the strength of the signal compared to noise.

The SNR expressed in decibels, it represents the logarithmic ratio of signal power to noise power.

The speed at which data is transmitted, measured in bits per second (bps).

The theoretical maximum data rate for a noiseless channel, calculated using the bandwidth and number of signal levels.

The theoretical maximum data rate for a noisy channel, calculated using the bandwidth and signal-to-noise ratio (SNR)

The data rate in a noisy channel is limited by the bandwidth and the signal-to-noise ratio (SNR).

The range of frequencies that a channel can pass, measured in Hertz.

The speed of bit transmission in a channel or link, measured in bits per second.

The bit rate is directly proportional to the baud rate multiplied by the number of bits per baud. In analog transmission, the baud rate is less than or equal to the bit rate.

The actual data transfer rate achieved over a network connection, measured in bits per second (bps).

Bandwidth refers to the potential capacity of a communication link, while throughput is the actual rate at which data is transferred.

Converting digital data (0s and 1s) into analog signals that can be transmitted over physical media like phone lines.

A device that uses digital-to-analog and analog-to-digital conversion to connect digital devices to analog communication lines.

Representing analog information using an analog signal. This technique is used when the transmission medium requires a specific frequency band.

A technique for converting analog signals to digital data by sampling the signal, quantizing the samples, and encoding them into binary digits.

Line coding, block coding, and scrambling. Line coding is always necessary, while block coding and scrambling are optional.

Guided and unguided. Guided media transmit through a physical cable, while unguided media use electromagnetic waves.

Radio waves (for Wireless LANs), microwaves (for terrestrial and satellite communication), and infrared waves (for remote controls).

Open Wire (least efficient), Coaxial Cable (better shielding), Optical Fiber (highest bandwidth), and Twisted Pair (most common).

Pulse Code Modulation (PCM) is used, where the analog signal is sampled, quantized, and encoded into binary digits.

Digital signals are less prone to noise and distortion, provide higher data rates, and enable more efficient error detection and correction.

A type of cable where two insulated wires are twisted together to reduce interference and improve signal transmission.

A cable with a central conductor surrounded by an insulator, a braided shield, and an outer jacket. Used for high-frequency signals and high bandwidth needs.

A cable that uses glass or plastic filaments to transmit light pulses representing data. Offers very high bandwidth and long transmission distances.

A common type of twisted pair cable without a metallic shield, typically used for indoor networking.

A type of twisted pair cable with a metallic braid or foil shield, offering improved protection against interference.

Solid cables have a single wire conductor, while stranded cables have multiple smaller wires. Stranded cables are more flexible but slightly more expensive.

The range of frequencies a transmission medium can carry. Higher bandwidth allows for faster data transmission.

Optical fiber cables offer the highest bandwidth, followed by coaxial cable, then twisted pair cable.