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In-phase And Quadrature Components
In electrical engineering, a sinusoid with angle modulation can be decomposed into, or synthesized from, two amplitude-modulated sinusoids that are offset in phase by one-quarter cycle (90 degrees or /2 radians). All three functions have the same center frequency. Such amplitude modulated sinusoids are known as the in-phase and quadrature components. In some contexts it is more convenient to refer to only the amplitude modulation (''baseband'') itself by those terms. Concept In vector analysis, a vector with polar coordinates and Cartesian coordinates can be represented as the sum of orthogonal components: Similarly in trigonometry, the angle sum identity expresses: : And in functional analysis, when is a linear function of some variable, such as time, these components are sinusoids, and they are orthogonal functions. A phase-shift of changes the identity to: : , in which case is the in-phase component. In both conventions is the in-phase amplitude modulation, w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quadrature Amplitude Modulation
Quadrature amplitude modulation (QAM) is the name of a family of digital modulation methods and a related family of analog modulation methods widely used in modern telecommunications to transmit information. It conveys two analog message signals, or two digital bit streams, by changing (''modulating'') the amplitudes of two carrier waves, using the amplitude-shift keying (ASK) digital modulation scheme or amplitude modulation (AM) analog modulation scheme. The two carrier waves are of the same frequency and are out of phase with each other by 90°, a condition known as orthogonality or quadrature. The transmitted signal is created by adding the two carrier waves together. At the receiver, the two waves can be coherently separated (demodulated) because of their orthogonality property. Another key property is that the modulations are low-frequency/low-bandwidth waveforms compared to the carrier frequency, which is known as the narrowband assumption. Phase modulation (analog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
In-phase And Quadrature Components Of Angle Modulation
In physics and mathematics, the phase of a 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 denoted \phi(t) and 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 \phi(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 \phi(t) is also a periodic function, with the same period as F, that repeatedly scans the same range ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IQ Mod Demod Block Diagram
An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term ''Intelligenzquotient'', his term for a scoring method for intelligence tests at University of Breslau he advocated in a 1912 book. Historically, IQ was a score obtained by dividing a person's mental age score, obtained by administering an intelligence test, by the person's chronological age, both expressed in terms of years and months. The resulting fraction (quotient) was multiplied by 100 to obtain the IQ score. For modern IQ tests, the raw score is transformed to a normal distribution with mean 100 and standard deviation 15. This results in approximately two-thirds of the population scoring between IQ 85 and IQ 115 and about 2.5 percent each above 130 and below 70. Scores from intelligence tests are estimates of intelligence. Unlike, for exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Single-sideband Modulation
In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves. A refinement of amplitude modulation, it uses transmitter power and bandwidth more efficiently. Amplitude modulation produces an output signal the bandwidth of which is twice the maximum frequency of the original baseband signal. Single-sideband modulation avoids this bandwidth increase, and the power wasted on a carrier, at the cost of increased device complexity and more difficult tuning at the receiver. Basic concept Radio transmitters work by mixing a radio frequency (RF) signal of a specific frequency, the carrier wave, with the audio signal to be broadcast. In AM transmitters this mixing usually takes place in the final RF amplifier (high level modulation). It is less common and much less efficient to do the mixing at low power and then amplify it in a linear a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polar Modulation
Polar modulation is analogous to quadrature modulation in the same way that polar coordinates are analogous to Cartesian coordinates. Quadrature modulation makes use of Cartesian coordinates, ''x'' and ''y''. When considering quadrature modulation, the ''x'' axis is called the ''I'' (in-phase) axis, and the ''y'' axis is called the ''Q'' (quadrature) axis. Polar modulation makes use of polar coordinates, ''r'' (amplitude) and ''Θ'' (phase). The quadrature modulator approach to digital radio transmission requires a linear RF power amplifier which creates a design conflict between improving power efficiency or maintaining amplifier linearity. Compromising linearity causes degraded signal quality, usually by adjacent channel degradation, which can be a fundamental factor in limiting network performance and capacity. Additional problems with linear RF power amplifiers, including device parametric restrictions, temperature instability, power control accuracy, wideband noise and pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phasor
In physics and engineering, a phasor (a portmanteau of phase vector) is a complex number representing a sinusoidal function whose amplitude (''A''), angular frequency (''ω''), and initial phase (''θ'') are time-invariant. It is related to a more general concept called analytic representation,Bracewell, Ron. ''The Fourier Transform and Its Applications''. McGraw-Hill, 1965. p269 which decomposes a sinusoid into the product of a complex constant and a factor depending on time and frequency. The complex constant, which depends on amplitude and phase, is known as a phasor, or complex amplitude, and (in older texts) sinor or even complexor. A common situation in electrical networks powered by time varying current is the existence of multiple sinusoids all with the same frequency, but different amplitudes and phases. The only difference in their analytic representations is the complex amplitude (phasor). A linear combination of such functions can be represented as a linear co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Constellation Diagram
A constellation diagram is a representation of a signal modulated by a digital modulation scheme such as quadrature amplitude modulation or phase-shift keying. It displays the signal as a two-dimensional ''xy''-plane scatter diagram in the complex plane at symbol sampling instants. In a manner similar to that of a phasor diagram, the angle of a point, measured counterclockwise from the horizontal axis, represents the phase shift of the carrier wave from a reference phase; the distance of a point from the origin represents a measure of the amplitude or power of the signal. In a digital modulation system, information is transmitted as a series of samples, each occupying a uniform time slot. During each sample, the carrier wave has a constant amplitude and phase, which is restricted to one of a finite number of values. So each sample encodes one of a finite number of "symbols", which in turn represent one or more binary digits (bits) of information. Each symbol is encoded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IQ Imbalance
IQ imbalance is a performance-limiting issue in the design of a class of radio receivers known as direct conversion receivers. These translate the received radio frequency (RF, or pass-band) signal directly from the carrier frequency f_c to baseband using a single mixing stage. Direct conversion receivers contain a '' local oscillator'' (LO) which generates both a sine wave at f_c and a copy delayed by 90°. These are individually mixed with the RF signal, producing what are known respectively as the ''in-phase'' and ''quadrature'' signals, labelled \texttt I and \texttt Q. However, in the analog domain, the phase difference is never exactly 90°. Neither is the gain perfectly matched between the parallel sections of circuitry dealing with the two signal paths. IQ imbalance results from these two imperfections, and is one of the two major drawbacks of direct-conversion receivers compared to traditional superheterodyne receivers. (The other is DC offset.) Their design must incl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carrier Frequency
In telecommunications, a carrier wave, carrier signal, or just carrier, is a waveform (usually sinusoidal) that is modulated (modified) with an information-bearing signal for the purpose of conveying information. This carrier wave usually has a much higher frequency than the input signal does. The purpose of the carrier is usually either to transmit the information through space as an electromagnetic wave (as in radio communication), or to allow several carriers at different frequencies to share a common physical transmission medium by frequency division multiplexing (as in a cable television system). The term originated in radio communication, where the carrier wave creates the waves which carry the information (modulation) through the air from the transmitter to the receiver. The term is also used for an unmodulated emission in the absence of any modulating signal. In music production, carrier signals can be controlled by a modulating signal to change the sound property of a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VI Phase
VI or Vi may refer to: Arts, entertainment and media Characters * Vi (League of Legends), a character from the ''League of Legends'' video game franchise *Vi (Buffy the Vampire Slayer), a minor character in the American TV series ''Buffy the Vampire Slayer'' *Vi, Violet Parr's nickname, a character of Walt Disney Pictures animated film ''The Incredibles'' *Vi Praskins, a major character in the 1950s American TV series '' Private Secretary'' Music * Submediant chord, symbolized "VI" or "vi" * ''VI'' (Circle Jerks album), 1987 * ''VI'' (The Danse Society album), 2015 * ''VI'' (Onslaught album), 2013 * ''VI'' (You Me at Six album), 2018 *'' Ice-T VI: Return of the Real'', an album by Ice-T, 1996 *VI Music, a Puerto Rican record label Magazines *''Voetbal International'', a prominent Dutch football (soccer) magazine * ''Vi'' (magazine), a Swedish lifestyle magazine Businesses and organizations *Vi Senior Living, a provider of retirement communities in the United States * Victoria Ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Shifter Using IQ Modulator
Phase or phases may refer to: Science * State of matter, or phase, one of the distinct forms in which matter can exist *Phase (matter), a region of space throughout which all physical properties are essentially uniform *Phase space, a mathematical space in which each possible state of a physical system is represented by a point — this equilibrium point is also referred to as a "microscopic state" ** Phase space formulation, a formulation of quantum mechanics in phase space *Phase (waves), the position of a point in time (an instant) on a waveform cycle ** Instantaneous phase, generalization for both cyclic and non-cyclic phenomena * AC phase, the phase offset between alternating current electric power in multiple conducting wires **Single-phase electric power, distribution of AC electric power in a system where the voltages of the supply vary in unison **Three-phase electric power, a common method of AC electric power generation, transmission, and distribution * Phase problem, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IQ Phasor Diagram
An intelligence quotient (IQ) is a total score derived from a set of standardized tests or subtests designed to assess human intelligence. The abbreviation "IQ" was coined by the psychologist William Stern for the German term ''Intelligenzquotient'', his term for a scoring method for intelligence tests at University of Breslau he advocated in a 1912 book. Historically, IQ was a score obtained by dividing a person's mental age score, obtained by administering an intelligence test, by the person's chronological age, both expressed in terms of years and months. The resulting fraction (quotient) was multiplied by 100 to obtain the IQ score. For modern IQ tests, the raw score is transformed to a normal distribution with mean 100 and standard deviation 15. This results in approximately two-thirds of the population scoring between IQ 85 and IQ 115 and about 2.5 percent each above 130 and below 70. Scores from intelligence tests are estimates of intelligence. Unlike, for exam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
