Data Communication Basics

The process of exchanging information between a source and a destination.

The goal of communication systems is to transmit information with low power, a high Signal-to-Noise Ratio (SNR), and a low probability of error, even with noise.

Any communication system has three main components: the transmitter, the channel, and the receiver.

A transmitter converts the information into a format suitable for transmission over the communication channel.

The communication channel is the medium that carries the information between the transmitter and receiver.

A receiver decodes the received information and presents it to the recipient.

The information source generates the message in a form that might not be electrical (e.g., voice, picture).

The source encoder converts the information from the source into a digital form, even if the original source was analog.

A process of converting a source signal into a format suitable for transmission over a communication channel, aiming to reduce redundancy and use minimal bits while ensuring ease of decoding back to the original signal.

The inverse process of source encoding, where the received encoded signal is converted back to the original source signal.

A process of manipulating digital signals to mitigate the effects of noise during transmission, ensuring reliable communication over noisy channels. It involves adding redundancy at the encoder and exploiting it at the decoder to correct errors.

The reverse process of channel encoding, where the redundancy added during encoding is used to correct errors introduced during transmission and recover the original signal.

A technique that modulates (varies one or more properties) a carrier signal using the information to be transmitted. This allows efficient transmission over a communication channel.

A type of noise caused by the superposition of two or more signals, often resulting from poor system design. It can lead to signal interference.

A factor to consider when selecting a communication system due to its impact on the quality and performance of the received signal.

A major factor in determining the type of communication system needed, as different applications have varying communication requirements (e.g., mobile vs. wired).

Intentional disruption or interference that aims to degrade the quality of a transmitted signal, preventing it from reaching its intended recipient.

The representation of data in a communication system. It is generated by the transmitter.

The information itself, originated by the application.

When the signal intensity changes smoothly over time, without abrupt jumps.

When the signal intensity stays constant for a period, then abruptly changes to another constant value.

Data that changes continuously (e.g., sound, temperature).

Data that uses discrete values (e.g., text, images).

Types of signals can be broadly categorized into analog and digital, mirroring the nature of the data they represent.

A signal that doesn't vary with time, like a constant DC voltage.

A signal that changes in discrete steps, like a digital signal.

A wave with a smooth, repeating pattern. It's characterized by amplitude, frequency, and phase.

The strength of the signal, measured in units like volts or amperes. It's the height of the wave.

The number of cycles the wave completes per second, measured in units like Hertz (Hz). It's the speed of the wave's oscillation.

The starting point of the wave relative to a reference point, measured in units like radians or degrees. It's the wave's initial position.

The process of breaking down a complex signal into its individual frequency components.

The range of frequencies present in a signal.