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Envelope Detection
An envelope detector (sometimes called a peak detector) is an electronic circuit that takes a (relatively) high-frequency signal as input and outputs the ''envelope'' of the original signal. Diode detector A simple form of envelope detector used in detectors for early radios is the diode detector. Its output approximates a voltage-shifted version of the input's upper envelope. Between the circuit's input and output is a diode that performs half-wave rectification, allowing substantial current flow only when the input voltage is around a diode drop higher than the output terminal. The output is connected to a capacitor of value C and resistor of value R in parallel to ground. The capacitor is charged as the input voltage approaches its positive peaks. At other times, the capacitor is gradually discharged through the resistor. The resistor and capacitor form a 1st-order low pass filter, which attenuates higher frequencies at a rate of -6 dB per octave above its cutoff fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
C Envelope Follower
C, or c, is the third letter of the Latin alphabet, used in the modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is ''cee'' (pronounced ), plural ''cees''. History "C" comes from the same letter as "G". The Semites named it gimel. The sign is possibly adapted from an Egyptian hieroglyph for a staff sling, which may have been the meaning of the name ''gimel''. Another possibility is that it depicted a camel, the Semitic name for which was ''gamal''. Barry B. Powell, a specialist in the history of writing, states "It is hard to imagine how gimel = "camel" can be derived from the picture of a camel (it may show his hump, or his head and neck!)". In the Etruscan language, plosive consonants had no contrastive voicing, so the Greek ' Γ' (Gamma) was adopted into the Etruscan alphabet to represent . Already in the Western Greek alphabet, Gamma first took a '' form in Early Etruscan, then '' in Classical Et ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Signal
Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths greater than , about the diameter of a grain of rice. Radio waves with frequencies above about 1 GHz and wavelengths shorter than 30 centimeters are called microwaves. Like all electromagnetic waves, radio waves in vacuum travel at the speed of light, and in the Earth's atmosphere at a slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna, which radiates the waves. They are received ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frequency Modulation
Frequency modulation (FM) is a signal modulation technique used in electronic communication, originally for transmitting messages with a radio wave. In frequency modulation a carrier wave is varied in its instantaneous frequency in proportion to a property, primarily the instantaneous amplitude, of a message signal, such as an audio signal. The technology is used in telecommunications, radio broadcasting, signal processing, and Run-length limited#FM: .280.2C1.29 RLL, computing. In Analog signal, analog frequency modulation, such as radio broadcasting of voice and music, the instantaneous frequency deviation, i.e. the difference between the frequency of the carrier and its center frequency, has a functional relation to the modulating signal amplitude. Digital data can be encoded and transmitted with a type of frequency modulation known as frequency-shift keying (FSK), in which the instantaneous frequency of the carrier is shifted among a set of frequencies. The frequencies m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude Modulation
Amplitude modulation (AM) is a signal modulation technique used in electronic communication, most commonly for transmitting messages with a radio wave. In amplitude modulation, the instantaneous amplitude of the wave is varied in proportion to that of the message signal, such as an audio signal. This technique contrasts with angle modulation, in which either the frequency of the carrier wave is varied, as in frequency modulation, or its Phase (waves), phase, as in phase modulation. AM was the earliest modulation method used for transmitting audio in radio broadcasting. It was developed during the first quarter of the 20th century beginning with Roberto Landell de Moura and Reginald Fessenden's radiotelephone experiments in 1900. This original form of AM is sometimes called double-sideband amplitude modulation (DSBAM), because the standard method produces sidebands on either side of the carrier frequency. Single-sideband modulation uses bandpass filters to eliminate one of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analytic
Analytic or analytical may refer to: Chemistry * Analytical chemistry, the analysis of material samples to learn their chemical composition and structure * Analytical technique, a method that is used to determine the concentration of a chemical compound or chemical element * Analytical concentration Mathematics * Abstract analytic number theory, the application of ideas and techniques from analytic number theory to other mathematical fields * Analytic combinatorics, a branch of combinatorics that describes combinatorial classes using generating functions * Analytic element method, a numerical method used to solve partial differential equations * Analytic expression or analytic solution, a mathematical expression using well-known operations that lend themselves readily to calculation * Analytic geometry, the study of geometry based on numerical coordinates rather than axioms * Analytic number theory, a branch of number theory that uses methods from mathematical analysis Mathema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bass Instrument
Bass ( ) (also called bottom end) describes tones of low (also called "deep") frequency, pitch and range from 16 to 250 Hz (C0 to middle C4) and bass instruments that produce tones in the low-pitched range C2-C4. They belong to different families of instruments and can cover a wide range of musical roles. Since producing low pitches usually requires a long air column or string, and for stringed instruments, a large hollow body, the string and wind bass instruments are usually the largest instruments in their families or instrument classes. Musical role When bass notes are played in a musical ensemble such an orchestra, they are frequently used to provide a counterpoint or counter-melody, in a harmonic context either to outline or juxtapose the progression of the chords, or with percussion to underline the rhythm. Rhythm section In popular music, the bass part, which is called the "bassline", typically provides harmonic and rhythmic support to the band. The bass player is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Filter
Electronic filters are a type of signal processing filter in the form of electrical circuits. This article covers those filters consisting of lumped-element model, lumped electronic components, as opposed to distributed-element filters. That is, using components and interconnections that, in analysis, can be considered to exist at a single point. These components can be in discrete packages or part of an integrated circuit. Electronic filters remove unwanted frequency components from the applied signal, enhance wanted ones, or both. They can be: *Passive filter, passive or active filter, active *analogue filter, analog or digital filter, digital *high-pass filter, high-pass, low-pass filter, low-pass, band-pass filter, band-pass, band-stop filter, band-stop (band-rejection; notch), or all-pass filter, all-pass. *discrete-time (sampled) or Continuous signal, continuous-time *linear filter, linear or non-linear filter, non-linear *infinite impulse response (IIR type) or finite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schottky Diode
The Schottky diode (named after the German physicist Walter H. Schottky), also known as Schottky barrier diode or hot-carrier diode, is a semiconductor diode formed by the junction of a semiconductor with a metal. It has a low forward voltage drop and a very fast switching action. The cat's-whisker detectors used in the early days of wireless and metal rectifiers used in early power applications can be considered primitive Schottky diodes. When sufficient forward voltage is applied, a current flows in the forward direction. A silicon p–n diode has a typical forward voltage of 600–700 mV, while the Schottky's forward voltage is 150–450 mV. This lower forward voltage requirement allows higher switching speeds and better system efficiency. Construction A metal–semiconductor junction is formed between a metal and a semiconductor, creating a Schottky barrier (instead of a semiconductor–semiconductor junction as in conventional diodes). Typical metals used ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germanium
Germanium is a chemical element; it has Symbol (chemistry), symbol Ge and atomic number 32. It is lustrous, hard-brittle, grayish-white and similar in appearance to silicon. It is a metalloid or a nonmetal in the carbon group that is chemically similar to silicon. Like silicon, germanium naturally Chemical reaction, reacts and forms complexes with oxygen in nature. Because it seldom appears in high concentration, germanium was found comparatively late in the Timeline of chemical element discoveries, discovery of the elements. Germanium ranks 50th Abundance of elements in Earth's crust, in abundance of the elements in the Earth's crust. In 1869, Dmitri Mendeleev Mendeleev's predicted elements, predicted its existence and some of its Chemical property, properties from its position on his periodic table, and called the element ekasilicon. On February 6, 1886, Clemens Winkler at Freiberg University found the new element, along with silver and sulfur, in the mineral argyrodite. Winkle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diode
A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance and conductance, resistance in one direction and high (ideally infinite) resistance in the other. A semiconductor diode, the most commonly used type today, is a Crystallinity, crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an Exponential function, exponential current–voltage characteristic. Semiconductor diodes were the first Semiconductor device, semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a Crystal, crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow through semiconductors, electrical insulation, insulators, or even through a vacuum as in electron beam, electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A archaism, term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''Electric current, current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains Electronics, electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alternating Current
Alternating current (AC) is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction. Alternating current is the form in which electric power is delivered to businesses and residences, and it is the form of electrical energy that consumers typically use when they plug kitchen appliances, televisions, Fan (machine), fans and electric lamps into a wall socket. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', respectively, as when they modify ''Electric current, current'' or ''voltage''. The usual waveform of alternating current in most electric power circuits is a sine wave, whose positive half-period corresponds with positive direction of the current and vice versa (the full period is called a ''wave cycle, cycle''). "Alternating current" most commonly refers to power distribution, but a wide range of other appl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
