1. Analog Communication - Analog Communication is a data transmitting technique in a format that utilizes continuous signals to transmit data including voice, image, video, electrons etc. An analog signal is a variable signal continuous in both time and amplitude which is generally carried by use of modulation.2.
History of Analog Communication –3. Amplitude Modulation - Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. AM works by varying the strength (amplitude) of the carrier in proportion to the waveform being sent.4. Angle Modulation - is a class of analog modulation.
These techniques are based on altering the angle (or phase) of a sinusoidal carrier wave to transmit data, as opposed to varying the amplitude, such as in AM transmission.5. Probability and Random Process –6. Noise in Analog System - As the signal is copied and re-copied, or transmitted over long distances, or electronically processed, the unavoidable noise introduced by each step in the signal path is additive, progressively degrading the signal-to-noise ratio, until in extreme cases the signal can be overwhelmed.7.
Digital Communication - Data transmission, digital transmission, or digital communications is the physical transfer of data (a digital bit stream) over a point-to-point or point-to-multipoint communication channel. Examples of such channels are copper wires, optical fiber, wireless communication channels, and storage media. The data are represented as an electromagnetic signal, such as an electrical voltage, radio wave, microwave, or infrared signal.8.
History of Digital Communication - Data (mainly but not exclusively informational) has been sent via non-electronic (e.g. optical, acoustic, mechanical) means since the advent of communication. Analog signal data has been sent electronically since the advent of the telephone. However, the first data electromagnetic transmission applications in modern time were telegraphy (1809) and teletypewriters (1906), which are both digital signals.
The fundamental theoretical work in data transmission and information theory by Harry Nyquist, Ralph Hartley, Claude Shannon and others during the early 20th century, was done with these applications in mind.9. Analog to Digital Conversion - An analog-to-digital converter (abbreviated ADC, A/D or A to D) is a device that converts a continuous physical quantity (usually voltage) to a digital number that represents the quantity's amplitude. The conversion involves quantization of the input, so it necessarily introduces a small amount of error.
Instead of doing a single conversion, an ADC often performs the conversions ("samples" the input) periodically. The result is a sequence of digital values that have converted a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal.10. Source Compression – In computer science and information theory, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation.]Compression can be either lossy or lossless.
Lossless compression reduces bits by identifying and eliminating statistical redundancy. No information is lost in lossless compression. Loss compression reduces bits by identifying unnecessary information and removing it. The process of reducing the size of a data file is popularly referred to as data compression, although its formal name is source coding (coding done at the source of the data before it is stored or transmitted).
11. Quantization - is the procedure of constraining something from a continuous set of values (such as the real numbers) to a relatively small discrete set (such as the integers).
