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Low-frequency Oscillator
Low-frequency oscillation (LFO) is an electronic frequency that is usually below 20 Hz and creates a rhythmic pulse or sweep. This is used to modulate musical equipment such as synthesizers to create audio effects such as vibrato, tremolo and phasing. History Low-frequency oscillation was introduced with modular synthesizers of the 1960s, such as the Moog synthesizer. Often the LFO effect was accidental, as there were myriad configurations that could be "patched" by the synth operator. LFOs have since appeared in some form on almost every synthesizer. More recently other electronic musical instruments, such as samplers and software synthesizers, have included LFOs to increase their sound alteration capabilities. Overview The primary oscillator circuits of a synthesizer are used to create the audio signals. An LFO is a secondary oscillator that operates at a significantly lower frequency than other oscillators, typically below 20 Hz — that is, below the range of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tremolo
In music, ''tremolo'' (), or ''tremolando'' (), is a trembling effect. There are multiple types of tremolo: a rapid repetition of a note, an alternation between two different notes, or a variation in volume. Tremolos may be either ''measured'', in which the exact rate of repetition or oscillation is specified, or ''unmeasured'', in which it is not (the understanding being in that case that it should be performed as rapidly as possible). Types of tremolo Rapid reiteration or oscillation The rapid reiteration of a single Musical note, note is a characteristic effect of String instrument#Bowing, bowed string instruments, obtained by rapidly moving the bow back and forth. However, the technique may be performed on any instrument on which it is practicable. (Indeed, a slow measured tremolo is simply a shorthand notation for an ordinary repetition of notes; thus, tremolo notation may appear in written music for any instrument.) The notation for this effect consists of one or mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sine Wave
A sine wave, sinusoidal wave, or sinusoid (symbol: ∿) is a periodic function, periodic wave whose waveform (shape) is the trigonometric function, trigonometric sine, sine function. In mechanics, as a linear motion over time, this is ''simple harmonic motion''; as rotation, it corresponds to ''uniform circular motion''. Sine waves occur often in physics, including wind waves, sound waves, and light waves, such as monochromatic radiation. In engineering, signal processing, and mathematics, Fourier analysis decomposes general functions into a sum of sine waves of various frequencies, relative phases, and magnitudes. When any two sine waves of the same frequency (but arbitrary phase (waves), phase) are linear combination, linearly combined, the result is another sine wave of the same frequency; this property is unique among periodic waves. Conversely, if some phase is chosen as a zero reference, a sine wave of arbitrary phase can be written as the linear combination of two sine wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronization
Synchronization is the coordination of events to operate a system in unison. For example, the Conductor (music), conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronous or ''in sync''—and those that are not are ''Asynchronous system, asynchronous''. Today, time synchronization can occur between systems around the world through satellite navigation signals and other time and frequency transfer techniques. Navigation and railways Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and Radionavigation-satellite service, satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine History of longitude, how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th cent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tempo
In musical terminology, tempo (Italian for 'time'; plural 'tempos', or from the Italian plural), measured in beats per minute, is the speed or pace of a given musical composition, composition, and is often also an indication of the composition's character or atmosphere. In classical music, tempo is typically indicated with an instruction at the start of a piece (often using conventional Italian terms) and, if a specific metrical pace is desired, is usually measured in beat (music), beats per minute (bpm or BPM). In modern classical compositions, a "metronome mark" in beats per minute, indicating only measured speed and not any form of expression, may supplement or replace the normal tempo marking, while in modern genres like electronic dance music, tempo will typically simply be stated in bpm. Tempo (the underlying pulse of the music) is one of the three factors that give a piece of music its texture (music), texture. The others are meter (music), meter, which is indicated by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waveform
In electronics, acoustics, and related fields, the waveform of a signal is the shape of its Graph of a function, graph as a function of time, independent of its time and Magnitude (mathematics), magnitude Scale (ratio), scales and of any displacement in time.David Crecraft, David Gorham, ''Electronics'', 2nd ed., , CRC Press, 2002, p. 62 ''Periodic waveforms'' repeat regularly at a constant wave period, period. The term can also be used for non-periodic or aperiodic signals, like chirps and pulse (signal processing), pulses. In electronics, the term is usually applied to time-varying voltages, electric current, currents, or electromagnetic fields. In acoustics, it is usually applied to steady periodic sounds — variations of air pressure, pressure in air or other media. In these cases, the waveform is an attribute that is independent of the frequency, amplitude, or phase shift of the signal. The waveform of an electrical signal can be visualized with an oscilloscope or an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude. Definitions Peak amplitude and semi-amplitude For symmetric periodic waves, like sine waves or triangle waves, ''peak amplitude'' and ''semi amplitude'' are the same. Peak amplitude In audio system measurements, telecommunications and others where the measurand is a signal that swings above and below a reference value but is not sinusoidal, peak amplitude is often used. If the reference is zero, this is the maximum absolute value of the signal; if the reference is a mean value ( DC component), the peak amplitude is the maximum ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Filter
An audio filter is a frequency-dependent circuit, working in the audio frequency range, 0 Hz to 20 kHz. Audio filters can amplify (boost), pass or attenuate (cut) some frequency ranges. Many types of filters exist for different audio applications including hi-fi stereo systems, musical synthesizers, effects units, sound reinforcement systems, instrument amplifiers and virtual reality systems. Types ;Low-pass :Low-pass filters pass through frequencies below their cutoff frequencies, and progressively attenuate frequencies above the cutoff frequency. Low-pass filters are used in audio crossovers to remove high-frequency content from signals being sent to a low-frequency subwoofer system. ;High-pass :A high-pass filter does the opposite, passing high frequencies above the cutoff frequency, and progressively attenuating frequencies below the cutoff frequency. A high-pass filter can be used in an audio crossover to remove low-frequency content from a signal being sent to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase (waves)
In physics and mathematics, the phase (symbol φ or ϕ) of a wave or other periodic function F of some real variable t (such as time) is an angle-like quantity representing the fraction of the cycle covered up to t. It is expressed in such a scale that it varies by one full turn as the variable t goes through each period (and F(t) goes through each complete cycle). It may be measured in any angular unit such as degrees or radians, thus increasing by 360° or 2\pi as the variable t completes a full period. This convention is especially appropriate for a sinusoidal function, since its value at any argument t then can be expressed as \varphi(t), the sine of the phase, multiplied by some factor (the amplitude of the sinusoid). (The cosine may be used instead of sine, depending on where one considers each period to start.) Usually, whole turns are ignored when expressing the phase; so that \varphi(t) is also a periodic function, with the same period as F, that repeatedly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillation
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum and alternating current. Oscillations can be used in physics to approximate complex interactions, such as those between atoms. Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating of the human heart (for circulation), business cycles in economics, predator–prey population cycles in ecology, geothermal geysers in geology, vibration of strings in guitar and other string instruments, periodic firing of nerve cells in the brain, and the periodic swelling of Cepheid variable stars in astronomy. The term ''vibration'' is precisely used to describe a mechanical oscillation. Oscillation, especially rapid oscillation, may be an undesirable phenomenon in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random Number Generator
Random number generation is a process by which, often by means of a random number generator (RNG), a sequence of numbers or symbols is generated that cannot be reasonably predicted better than by random chance. This means that the particular outcome sequence will contain some patterns detectable in hindsight but impossible to foresee. True random number generators can be '' hardware random-number generators'' (HRNGs), wherein each generation is a function of the current value of a physical environment's attribute that is constantly changing in a manner that is practically impossible to model. This would be in contrast to so-called "random number generations" done by ''pseudorandom number generators'' (PRNGs), which generate numbers that only look random but are in fact predetermined—these generations can be reproduced simply by knowing the state of the PRNG. Various applications of randomness have led to the development of different methods for generating random data. Some of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rectifier
A rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction. The process is known as ''rectification'', since it "straightens" the direction of current. Physically, rectifiers take a number of forms, including Vacuum tube#Diodes, vacuum tube diodes, wet chemical cells, mercury-arc valves, stacks of copper and selenium rectifier, selenium oxide plates, Diode#Semiconductor diodes, semiconductor diodes, silicon-controlled rectifiers and other silicon-based semiconductor switches. Historically, even synchronous electromechanical switches and motor-generator sets have been used. Early radio receivers, called crystal radios, used a "Crystal detector#Cat whisker detector, cat's whisker" of fine wire pressing on a crystal of galena (lead sulfide) to serve as a point-contact rectifier or "crystal detector". Rectifiers have many uses, but are often found serving as component ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
