|
Balanced Audio
Balanced audio is a method of interconnecting audio equipment using balanced interfaces. This type of connection is very important in sound recording and production because it allows the use of long cables while reducing susceptibility to external noise caused by electromagnetic interference. The balanced interface guarantees that induced noise appears as common-mode voltages at the receiver which can be rejected by a differential device. Balanced connections typically use shielded twisted-pair cable and three-conductor connectors. The connectors are usually three-pin XLR or TRS phone connectors. When used in this manner, each cable carries one channel, therefore stereo audio (for example) would require two of them. A common misconception is that balanced audio requires the signal source to deliver equal waveforms of opposite polarity to the two signal conductors of the balanced line. However, many balanced devices actively drive only one side of the line, but do so at an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise Rejection On Balanced Line
Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arises when the brain receives and perceives a sound. Acoustic noise is any sound in the acoustic domain, either deliberate (e.g., music or speech) or unintended. In contrast, noise in electronics may not be audible to the human ear and may require instruments for detection. In audio engineering, noise can refer to the unwanted residual electronic noise signal that gives rise to acoustic noise heard as a hiss. This signal noise is commonly measured using A-weighting or ITU-R 468 weighting. In experimental sciences, noise can refer to any random fluctuations of data that hinders perception of a signal. Measurement Sound is measured based on the amplitude and frequency of a sound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Amplifier
A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs. It is an analog circuit with two inputs V_\text^- and V_\text^+ and one output V_\text, in which the output is ideally Proportionality (mathematics), proportional to the difference between the two voltages: : V_\text = A(V_\text^+ - V_\text^-), where A is the Gain (electronics), gain of the amplifier. Single amplifiers are usually implemented by either adding the appropriate feedback resistors to a standard Operational amplifier, op-amp, or with a dedicated integrated circuit containing internal feedback resistors. It is also a common sub-component of larger integrated circuits handling analog signals. Mathematics of the amplifier : V_\text = A_\text(V_\text^+ - V_\text^-), where V_\text^+ and V_\text^- are the input voltages, and A_\text is the differential gain. In practice, however, the gain is not quite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Signal Integrity
Signal integrity or SI is a set of measures of the quality of an electrical signal. In digital electronics, a stream of binary values is represented by a voltage (or current) waveform. However, digital signals are fundamentally analog signal, analog in nature, and all signals are subject to effects such as electrical noise, noise, distortion, and loss. Over short distances and at low bit rates, a simple conductor can transmit this with sufficient fidelity. At high bit rates and over longer distances or through various mediums, various effects can degrade the electrical signal to the point where errors occur and the system or device fails. Signal integrity engineering is the task of analyzing and mitigating these effects. It is an important activity at all levels of electronics packaging and assembly, from internal connections of an integrated circuit (IC), A survey of the field of electronic design automation. Portions of IC section of this article were derived (with permission) fro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanced Circuit
In electrical engineering, a balanced circuit is electronic circuitry for use with a balanced line, or the balanced line itself. Balanced lines are a common method of Signal transmission, transmitting many types of electrical Signal (electronics), signals between two points on two wires. In a balanced line, the two signal lines are of a Impedance matching, matched impedance to help ensure that Electromagnetic interference, interference, Electromagnetic induction, induced in the line, is common-mode signal, common-mode and can be removed at the receiving end by circuitry with good common-mode rejection. To maintain the balance, circuit blocks which interface to the line or are connected in the line must also be balanced. Balanced lines work because the interfering Electronic noise, noise from the surrounding environment induces equal noise voltages into both wires. By measuring the voltage difference between the two wires at the receiving end, the original signal is recovered wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Supply Rejection Ratio
In electronic systems, power supply rejection ratio (PSRR), also supply-voltage rejection ratio (''k''SVR; SVR), is a term widely used to describe the capability of an electronic circuit to suppress any power supply variations to its output signal. In the specifications of operational amplifiers, the PSRR is defined as the ratio of the change in supply voltage to the equivalent (differential) output voltage it produces, often expressed in decibels. An ideal op-amp would have infinite PSRR, as the device should have no change to the output voltage with any changes to the power supply voltage. The output voltage will depend on the feedback circuit, as is the case of regular input offset voltages. But testing is not confined to DC (zero frequency); often an operational amplifier will also have its PSRR given at various frequencies (in which case the ratio is one of RMS amplitudes of sinewaves present at a power supply compared with the output, with gain taken into account). Unwanted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Headroom (audio Signal Processing)
In digital and analog audio, headroom refers to the amount by which the signal-handling capabilities of an audio system can exceed a designated nominal level. Headroom can be thought of as a safety zone allowing transient audio peaks to exceed the nominal level without damaging the system or the audio signal, e.g., via clipping. Standards bodies differ in their recommendations for nominal level and headroom. Digital audio In digital audio, headroom is defined as the amount by which digital full scale (FS) exceeds the nominal level in decibels (dB). The European Broadcasting Union (EBU) specifies several nominal levels and resulting headroom for different applications. Analog audio In analog audio, headroom can mean low-level signal capabilities as well as the amount of extra power reserve available within the amplifiers that drive the loudspeakers. Alignment level Alignment level is an anchor point 9 dB below the nominal level, a reference level that exists th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nominal Level
Nominal level is the operating level at which an electronic signal processing device is designed to operate. The electronic circuits that make up such equipment are limited in the maximum signal they can handle and the low-level internally generated electronic noise they add to the signal. The difference between the internal noise and the maximum level is the device's dynamic range. The nominal level is the level that these devices were designed to operate at, for best dynamic range and adequate headroom. When a signal is chained with improper gain staging through many devices, clipping may occur or the system may operate with reduced dynamic range. In audio, a related measurement, signal-to-noise ratio, is usually defined as the difference between the nominal level and the noise floor, leaving the headroom as the difference between nominal and maximum output. The measured level is a time average, meaning that the peaks of audio signals regularly exceed the measured average l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Source Impedance
In electrical engineering, the output impedance of an electrical network is the measure of the opposition to current flow ( impedance), both static ( resistance) and dynamic ( reactance), into the load network being connected that is ''internal'' to the electrical source. The output impedance is a measure of the source's propensity to drop in voltage when the load draws current, the source network being the portion of the network that transmits and the load network being the portion of the network that consumes. Because of this the output impedance is sometimes referred to as the source impedance or internal impedance. Description All devices and connections have non-zero resistance and reactance, and therefore no device can be a perfect source. The output impedance is often used to model the source's response to current flow. Some portion of the device's measured output impedance may not physically exist within the device; some are artifacts that are due to the chemical, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; ) is an international standards organization that prepares and publishes international standards for all electrical, electronics, electronic and related technologies. IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology, and marine energy, as well as many others. The IEC also manages four global conformity assessment systems that certify whether equipment, system or components conform to its international standards. All electrotechnologies are covered by IEC Standards, including energy production and distribution, electronics, magnetics and electromagnetics, electroacoustics, multimedia, telecommunications and medical technology, as well as associated general disciplines such as terminology and symbols, electromagnetic compatibility, measurement and performance, dependa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Polarity
The following Outline (list), outline is provided as an overview of and topical guide to electrical polarity (also called electric polarity). Positive and negative polarity * In electrical engineering, electrical polarity defines the direction in which the electrical current would flow once a source is connected; usually used for the direct current sources, where terminals are traditionally labeled with polarity symbols + (positive) and - (negative), with the conventional current chosen to flow from the positive to negative terminal. ** By analogy, when in electronics a signal is observed across two terminals, the measurement of voltage between the terminals yields opposing signs for the positive and negative polarity. * In physics and chemistry, electric polarity defines the electric charge separation into positive and negative charges within a system or molecule (for example, water molecules have unequal distribution of electrons between the oxygen and hydrogen atoms). The q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Signaling
Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conductors can be wires in a twisted-pair or ribbon cable or traces on a printed circuit board. Electrically, the two conductors carry voltage signals which are equal in magnitude, but of opposite polarity. The receiving circuit responds to the difference between the two signals, which results in a signal with a magnitude twice as large. The symmetrical signals of differential signalling may be referred to as ''balanced'', but this term is more appropriately applied to balanced circuits and balanced lines which reject common-mode interference when fed into a differential receiver. Differential signalling does not make a line balanced, nor does noise rejection in balanced circuits require differential signalling. Differential signalli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Loop (electricity)
In an electrical system, a ground loop or earth loop occurs when two points of a circuit are intended to have the same ground reference potential but instead have a different potential between them. This is typically caused when enough current is flowing in the connection between the two ground points to produce a voltage drop and cause the two points to be at different potentials. Current may be produced in a ground loop by electromagnetic induction. Ground loops are a major cause of noise, hum, and interference in audio, video, and computer systems. Wiring practices that protect against ground loops include ensuring that all vulnerable signal circuits are referenced to one point as ground. The use of differential signaling can provide rejection of ground-induced interference. The removal of ground connections to equipment in an effort to eliminate ground loops will also eliminate the protection the safety ground connection is intended to provide. Description A ground l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
