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Analog Recording
Analog recording is a technique used for the recording of analog signals which, among many possibilities, allows analog audio for later playback. Analog audio recording began with mechanical systems such as the phonautograph and phonograph. Later, electronic techniques such as wire and tape recording were developed. Analog recording methods store analog signals directly in or on the media. The signal may be stored as a physical texture on a phonograph record, or a fluctuation in the field strength of a magnetic recording. Analog transmission methods use analog signals to distribute audio content. These are in contrast to digital audio where an analog signal is sampled and quantized to produce a digital signal which is represented, stored and transmitted as discrete numbers. See also * Comparison of analog and digital recording * History of sound recording * Timeline of audio formats An audio format is a medium for sound recording and reproduction. The term is applied to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog Signal
An analog signal or analogue signal (see spelling differences) is any continuous signal representing some other quantity, i.e., ''analogous'' to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies continuously with the pressure of the sound waves. In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized values which imposes some bandwidth and dynamic range constraints on the representation. The term ''analog signal'' usually refers to electrical signals; however, mechanical, pneumatic, hydraulic and other systems may also convey or be considered analog signals. Representation An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. In an electrical signal, the voltage, current, or frequency of the signal may be varied to represent the information. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signal (signal Processing)
In the context of digital signal processing (DSP), a digital signal is a discrete time, quantized amplitude signal. In other words, it is a sampled signal consisting of samples that take on values from a discrete set (a countable set that can be mapped one-to-one to a subset of integers). If that discrete set is finite, the discrete values can be represented with digital words of a finite width. Most commonly, these discrete values are represented as fixed-point words (either proportional to the waveform values or companded) or floating-point words. The process of analog-to-digital conversion produces a digital signal. The conversion process can be thought of as occurring in two steps: # sampling, which produces a continuous-valued discrete-time signal, and # quantization, which replaces each sample value with an approximation selected from a given discrete set (for example, by truncating or rounding). It can be shown that an analog signal can be reconstructed after c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recording
A record, recording or records may refer to: An item or collection of data Computing * Record (computer science), a data structure ** Record, or row (database), a set of fields in a database related to one entity ** Boot sector or boot record, record used to start an operating system ** Storage record, a basic input/output structure Documents * Record, a document ** Business record, of economic transactions ** Criminal record, a list of a person's criminal convictions ** Docket (court), the summary of proceedings in a court (US) ** Medical record, of a person's medical history and treatments ** Minutes, a summary of the proceedings at a meeting ** Public records, information that has been filed or recorded by public agencies ** Recording (real estate), the act of documenting real estate transactions ** Service record, usually associated with military service ** Transcript (law), a verbatim ''record'' of some proceedings, in particular a court transcript is a record of a law co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Media Technology
Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different elementary particles, theoretically with the same amount of matter, have nonetheless different masses. Mass in modern physics has multiple definitions which are conceptually distinct, but physically equivalent. Mass can be experimentally defined as a measure of the body's inertia, meaning the resistance to acceleration (change of velocity) when a net force is applied. The object's mass also determines the strength of its gravitational attraction to other bodies. The SI base unit of mass is the kilogram (kg). In physics, mass is not the same as weight, even though mass is often determined by measuring the object's weight using a spring scale, rather than balance scale comparing it directly with known masses. An object on the Moon would weigh less t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film And Video Terminology
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere through the use of moving images. These images are generally accompanied by sound and, more rarely, other sensory stimulations. The word "cinema", short for cinematography, is often used to refer to filmmaking and the film industry, and to the art form that is the result of it. Recording and transmission of film The moving images of a film are created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual effects. Before the introduction of digital production, series of still images were recorded on a strip of chemically sensitize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Film And Video Technology
A film also called a movie, motion picture, moving picture, picture, photoplay or (slang) flick is a work of visual art that simulates experiences and otherwise communicates ideas, stories, perceptions, feelings, beauty, or atmosphere through the use of moving images. These images are generally accompanied by sound and, more rarely, other sensory stimulations. The word "cinema", short for cinematography, is often used to refer to filmmaking and the film industry, and to the art form that is the result of it. Recording and transmission of film The moving images of a film are created by photographing actual scenes with a motion-picture camera, by photographing drawings or miniature models using traditional animation techniques, by means of CGI and computer animation, or by a combination of some or all of these techniques, and other visual effects. Before the introduction of digital production, series of still images were recorded on a strip of chemically sensitize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timeline Of Audio Formats
An audio format is a medium for sound recording and reproduction. The term is applied to both the physical recording media and the recording formats of the audio content—in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to store the data. Music is recorded and distributed using a variety of audio formats, some of which store additional information. Timeline of audio format developments See also * Timeline of video formats * Format war * Audio data compression References External links History of Recording TechnologiesMuseum Of Obsolete Media – Audio Formats {{DEFAULTSORT:Audio Format Technology timelines audio Audio most commonly refers to sound, as it is transmitted in signal form. It may also refer to: Sound *Audio signal, an electrical representation of sound *Audio frequency, a frequency in the audio spectrum *Digital audio, representation of sound ... Obsolete tec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Sound Recording
The history of sound recording - which has progressed in waves, driven by the invention and commercial introduction of new technologies — can be roughly divided into four main periods: * The Acoustic era (1877–1925) * The Electrical era (1925–1945) * The Magnetic era (1945–1975) * The Digital era (1975–present) Experiments in capturing sound on a recording medium for preservation and reproduction began in earnest during the Industrial Revolution of the 1800s. Many pioneering attempts to record and reproduce sound were made during the latter half of the 19th century – notably Édouard-Léon Scott de Martinville's phonautograph of 1857 – and these efforts culminated in the invention of the phonograph by Thomas Edison in 1877. Digital recording emerged in the late 20th century and has since flourished with the popularity of digital music and online streaming services. Overview The Acoustic Era (1877–1925) The earliest practical recording technol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comparison Of Analog And Digital Recording
Sound can be recorded and stored and played using either digital or analog techniques. Both techniques introduce errors and distortions in the sound, and these methods can be systematically compared. Musicians and listeners have argued over the superiority of digital versus analog sound recordings. Arguments for analog systems include the absence of fundamental error mechanisms which are present in digital audio systems, including aliasing and quantization noise. Advocates of digital point to the high levels of performance possible with digital audio, including excellent linearity in the audible band and low levels of noise and distortion. Two prominent differences in performance between the two methods are the bandwidth and the signal-to-noise ratio (S/N ratio). The bandwidth of the digital system is determined, according to the Nyquist frequency, by the sample rate used. The bandwidth of an analog system is dependent on the physical and electronic capabilities of the analog c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete Number
In mathematics and statistics, a quantitative variable may be continuous or discrete if they are typically obtained by ''measuring'' or ''counting'', respectively. If it can take on two particular real values such that it can also take on all real values between them (even values that are arbitrarily close together), the variable is continuous in that interval. If it can take on a value such that there is a non-infinitesimal gap on each side of it containing no values that the variable can take on, then it is discrete around that value. In some contexts a variable can be discrete in some ranges of the number line and continuous in others. Continuous variable A continuous variable is a variable whose value is obtained by measuring, i.e., one which can take on an uncountable set of values. For example, a variable over a non-empty range of the real numbers is continuous, if it can take on any value in that range. The reason is that any range of real numbers between a and b wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantization (signal Processing)
Quantization, in mathematics and digital signal processing, is the process of mapping input values from a large set (often a continuous set) to output values in a (countable) smaller set, often with a finite number of elements. Rounding and truncation are typical examples of quantization processes. Quantization is involved to some degree in nearly all digital signal processing, as the process of representing a signal in digital form ordinarily involves rounding. Quantization also forms the core of essentially all lossy compression algorithms. The difference between an input value and its quantized value (such as round-off error) is referred to as quantization error. A device or algorithmic function that performs quantization is called a quantizer. An analog-to-digital converter is an example of a quantizer. Example For example, rounding a real number x to the nearest integer value forms a very basic type of quantizer – a ''uniform'' one. A typical (''mid-tread'') uni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonautograph
The phonautograph is the earliest known device for recording sound. Previously, tracings had been obtained of the sound-producing vibratory motions of tuning forks and other objects by physical contact with them, but not of actual sound waves as they propagated through air or other media. Invented by Frenchman Édouard-Léon Scott de Martinville, it was patented on March 25, 1857. It transcribed sound waves as undulations or other deviations in a line traced on smoke-blackened paper or glass. Intended solely as a laboratory instrument for the study of acoustics, it could be used to visually study and measure the amplitude envelopes and waveforms of speech and other sounds, or to determine the frequency of a given musical pitch by comparison with a simultaneously recorded reference frequency. Apparently, it did not occur to anyone before the 1870s that the recordings, called phonautograms, contained enough information about the sound that they could, in theory, be used to recre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
