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Referred-to-input
Equivalent input (also input-referred, referred-to-input (RTI), or input-related), is a method of referring to the signal or noise level at the output of a system as if it were due to an input to the same system. This input's value is called the Equivalent input. This is accomplished by removing all signal changes (e.g. amplifier gain, transducer sensitivity, etc.) to get the units to match the input. Examples Equivalent input noise A microphone converts acoustical energy to electrical energy. Microphones have some level of electrical noise at their output. This noise may have contributions from random diaphragm movement, thermal noise, or a dozen other sources, but those can all be thought of as an imaginary acoustic noise source injecting sound into the (now noiseless) microphone. The units on this noise are no longer volts, but units of sound pressure (pascals or dBSPL), which can be directly compared to the desired sound pressure inputs. This is called ''equivalent input ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost the voltage or current ( power, voltage or current amplifier). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude of a signal applied to its input terminals, producing a greater amplitude signal at its output. The ratio of output to input voltage, current, or power is termed gain (voltage, current, or power gain). An amplifier, by definition has gain greater than unity (if the gain is less than unity, the device is an attenuator). An amplifier can either be a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Noise
A thermal column (or thermal) is a rising mass of buoyant air, a convective current in the atmosphere, that transfers heat energy vertically. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example of convection, specifically atmospheric convection. Thermals on Earth The Sun warms the ground, which in turn warms the air directly above. The warm air near the surface expands, becoming less dense than the surrounding air. The lighter air rises and cools due to its expansion in the lower pressure at higher altitudes. It stops rising when it has cooled to the same temperature, thus density, as the surrounding air. Associated with a thermal is a downward flow surrounding the thermal column. The downward-moving exterior is caused by colder air being displaced at the top of the thermal. The size and strength of thermals are influenced by the properties of the lower atmosphere (the ''troposphere''). When the air is cold, bubbles of wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. It is one of the top 10 semiconductor companies worldwide based on sales volume. The company's focus is on developing analog chips and embedded processors, which account for more than 80% of its revenue. TI also produces TI digital light processing technology and education technology products including calculators, microcontrollers, and multi-core processors. The company holds 45,000 patents worldwide as of 2016. Texas Instruments emerged in 1951 after a reorganization of Geophysical Service Incorporated, a company founded in 1930 that manufactured equipment for use in the seismic industry, as well as defense electronics. TI produced the world's first commercial silicon transistor in 1954, and the same year designed and manufac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hearing
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory science. Sound may be heard through solid, liquid, or gaseous matter. It is one of the traditional five senses. Partial or total inability to hear is called hearing loss. In humans and other vertebrates, hearing is performed primarily by the auditory system: mechanical waves, known as vibrations, are detected by the ear and transduced into nerve impulses that are perceived by the brain (primarily in the temporal lobe). Like touch, audition requires sensitivity to the movement of molecules in the world outside the organism. Both hearing and touch are types of mechanosensation. Hearing mechanism There are three main components of the human auditory system: the outer ear, the middle ear, and the inner ear. Outer ear Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic Artifact
In sound and music production, sonic artifact, or simply artifact, refers to sonic material that is accidental or unwanted, resulting from the editing or manipulation of a sound. Types Because there are always technical restrictions in the way a sound can be recorded (in the case of acoustic sounds) or designed (in the case of synthesised or processed sounds), sonic errors often occur. These errors are termed artifacts (or sound/sonic artifacts), and may be pleasing or displeasing. A sonic artifact is sometimes a type of digital artifact, and in some cases is the result of data compression (not to be confused with dynamic range compression, which also may create sonic artifacts). Often an artifact is deliberately produced for creative reasons. For example to introduce a change in timbre of the original sound or to create a sense of cultural or stylistic context. A well-known example is the overdriving of an electric guitar or electric bass signal to produce a clipped, distort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromagnetic Interference
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction. The disturbance may degrade the performance of the circuit or even stop it from functioning. In the case of a data path, these effects can range from an increase in error rate to a total loss of the data. Both man-made and natural sources generate changing electrical currents and voltages that can cause EMI: ignition systems, cellular network of mobile phones, lightning, solar flares, and auroras (northern/southern lights). EMI frequently affects AM radios. It can also affect mobile phones, FM radios, and televisions, as well as observations for radio astronomy and atmospheric science. EMI can be used intentionally for radio jamming, as in electronic warfare. History Since the earliest days of rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DBSPL
Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured using a microphone, and in water with a hydrophone. The SI unit of sound pressure is the pascal (Pa). Mathematical definition A sound wave in a transmission medium causes a deviation (sound pressure, a ''dynamic'' pressure) in the local ambient pressure, a ''static'' pressure. Sound pressure, denoted ''p'', is defined by p_\text = p_\text + p, where * ''p''total is the total pressure, * ''p''stat is the static pressure. Sound measurements Sound intensity In a sound wave, the complementary variable to sound pressure is the particle velocity. Together, they determine the sound intensity of the wave. ''Sound intensity'', denoted I and measured in W· m−2 in SI units, is defined by \mathbf I = p \mathbf v, where * ''p'' is the sound pressure, * v is the particle velocity. Acousti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pascal (unit)
The pascal (symbol: Pa) is the unit of pressure in the International System of Units (SI), and is also used to quantify internal pressure, stress, Young's modulus, and ultimate tensile strength. The unit, named after Blaise Pascal, is defined as one newton per square metre and is equivalent to 10 barye (Ba) in the CGS system. The unit of measurement called standard atmosphere (atm) is defined as 101,325 Pa. Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa), which is equal to one millibar, and the kilopascal (1 kPa = 1000 Pa), which is equal to one centibar. Meteorological observations typically report atmospheric pressure in hectopascals per the recommendation of the World Meteorological Organization, thus a standard atmosphere (atm) or typical sea-level air pressure is about 1013 hPa. Reports in the United States typically use inches of mercury or millibars (hectopascals). In Canada these reports are given in ki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volt
The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Definition One volt is defined as the electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points. Equivalently, it is the potential difference between two points that will impart one joule of energy per coulomb of charge that passes through it. It can be expressed in terms of SI base units ( m, kg, s, and A) as : \text = \frac = \frac = \frac. It can also be expressed as amperes times ohms (current times resistance, Ohm's law), webers per second (magnetic flux per time), watts per ampere (power per current), or joules per coulomb (energy per charge), which is also equivalent to electronvolts per elementary charge: : \text = \text\Omega = \fra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diaphragm (acoustics)
In the field of acoustics, a diaphragm is a transducer intended to inter-convert mechanical vibrations to sounds, or vice versa. It is commonly constructed of a thin membrane or sheet of various materials, suspended at its edges. The varying air pressure of sound waves imparts mechanical vibrations to the diaphragm which can then be converted to some other type of signal; examples of this type of diaphragm are found in microphones and the human eardrum. Conversely a diaphragm vibrated by a source of energy beats against the air, creating sound waves. Examples of this type of diaphragm are loudspeaker cones and earphone diaphragms and are found in air horns. Loudspeaker In a dynamic loudspeaker, a diaphragm is the thin, semi-rigid membrane attached to the voice coil, which moves in a magnetic gap, vibrating the diaphragm, and producing sound. It can also be called a cone, though not all speaker diaphragms are cone-shaped. Diaphragms are also found in headphones. Quality mid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gain (electronics)
In electronics, gain is a measure of the ability of a two-port circuit (often an amplifier) to increase the power or amplitude of a signal from the input to the output port by adding energy converted from some power supply to the signal. It is usually defined as the mean ratio of the signal amplitude or power at the output port to the amplitude or power at the input port. It is often expressed using the logarithmic decibel (dB) units ("dB gain"). A gain greater than one (greater than zero dB), that is amplification, is the defining property of an active component or circuit, while a passive circuit will have a gain of less than one. The term ''gain'' alone is ambiguous, and can refer to the ratio of output to input voltage (''voltage gain''), current (''current gain'') or electric power (''power gain''). In the field of audio and general purpose amplifiers, especially operational amplifiers, the term usually refers to voltage gain, but in radio frequency amplifiers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. 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 wave. Amplitude measures how forceful the wave is. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
