что такое equivalent input noise voltage
equivalent input noise voltage
Смотреть что такое «equivalent input noise voltage» в других словарях:
Noise temperature — In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce… … Wikipedia
Noise (electronics) — Electronic noise [1] is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal noise is… … Wikipedia
Equivalent noise resistance — In telecommunication, an equivalent noise resistance is a quantitative representation in resistance units of the spectral density of a noise voltage generator, given byR n = frac
Noise (audio) — Noise in audio, recording, and broadcast systems refers to the residual low level sound (usually hiss and hum) that is heard in quiet periods of a programme. In audio engineering, it can refer either to the acoustic noise from loudspeakers, or to … Wikipedia
Noise — This article is about noise as an unwanted phenomenon. For other uses, see Noise (disambiguation). NASA researchers at Glenn Research Center conducting tests on aircraft engine noise in 1967 In common use, the word noise means any unwanted … Wikipedia
Noise reduction — For sound proofing, see soundproofing. For scientific aspects of noise reduction of machinery and products, see noise control. Noise reduction is the process of removing noise from a signal. All recording devices, both analogue or digital, have… … Wikipedia
Voltage regulator tube — A voltage regulator tube (VR tube) is an electronic component used as a shunt regulator to hold a voltage constant at a pre determined level.Physically, these devices resemble vacuum tubes, but there are two main differences: * Their glass… … Wikipedia
Input impedance — The input impedance, load impedance, or external impedance of a circuit or electronic device is the Thévenin equivalent impedance looking into its input.In audio systemsGenerally in audio and hi fi, the input impedance of components is several… … Wikipedia
Electronic noise — is an unwanted signal characteristic of all electronic circuits. Depending on the circuit, the noise put out by electronic devices can vary greatly. This noise comes from many different electronic effects.Thermal noise and shot noise are inherent … Wikipedia
Signal-to-noise ratio — For signal to noise ratio in statistics, see Cohen s d. Signal to noise ratio (often abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined… … Wikipedia
Current-to-voltage converter — In electronics, a transimpedance amplifier is an amplifier that converts current to voltage. Its input ideally has zero impedance, and the input signal is a current. Its output may have low impedance, or in high frequency applications, may be… … Wikipedia
Модульные синтезаторы
Сайт об электронике, модулях, синтезаторах и DIY
Снижение шумности Doepfer A-138 с помощью OP470
При работе с модульной системой одним из неизбежно используемых элементов является микшер — им смешиваются сигналы с осцилляторов, смешиваются управляющие напряжения (линейными версиями), могут смешиваться Gate испульсы и т.д. Микшеры, равно как и VCA или фильтры, содержат усилители. В случае конкретно микшера или сумматора, мы имеем дело с операционным усилителем работающим с незначительным коэффициентом усиления, который равен числу каналов или немного его превышает.
К сожалению, сложные компоненты такие как ОУ довольно шумны. Более того, микшерам часто приходится работать с широким динамическим диапазоном, когда сигнал на пике граничит с напряжением питания ОУ. Всё это может привести к шумности всей системы в целом. Бывали ли у вас ситуации, когда вы сделали очень приятный звук своими заказными VCO, смягчили звук НЧ-фильтром, настроили какие-либо модуляции, но всё портит связка VCA-микшер? Вы пытаетесь увеличить громкость звука, но либо перегружается вход микшера, либо тепловой шум становится явно слышимым. Это одна из причин, почему модули должны соответствовать друг другу по уровню качества, а следовательно, ключевые электронные компоненты должны быть точными и дорогими.
Я провёл небольшое исследование касательно шумовых характеристик операционных усилителей и провёл серию экспериментов со своей модульной системой. Вот что я обнаружил.
Схема микшера Doepfer A-138 исключительно проста: 4 пассивных аттенюатора построенных вокруг счетверённого ОУ и дополнительный аттенюатор для общего уровня громкости. Вот и всё, но эта система может быть довольно легко перегружена и она оказывается довольно шумна. При одинаковом уровне громкости, система при которой источник звука выводится сразу после VCA, оказывается менее шумной, чем идентичная цепочка также пропущенная через один канал A-138.
Вот модели ОУ, которые обычно Doepfer использует в своих системах:
LM324, TL062, TL064, TL084.
Посмотрим на их характеристики взятые из даташитов ST и AD:
Как можно видеть, LM324 — далеко не лучший из существующих на свете ОУ для звука, хотя на самом деле эта модель куда лучше многих других, кои годятся разве что для использования в схемах фильтрации питания.
Теперь посмотрим на современную микросхему Analog Devices. OP470 — высококлассный операционный усилитель специально предназначенный для аудио. Он имеет одни из лучших характеристик и имеет вполне обычные для использования в модульном синтезе требования к питанию и входному току : питание до ±18В, Rail-to-rail вход, высокая линейность, и т.п. Кроме того, он по выводам совместим с LM324 (Не все высококачественные ОУ имеют ту же цоколёвку). Так что он отлично подходит в качестве прямой замены ОУ используемых в некоторых модулях.
Было бы интересно услышать о других подобных удачных заменах.
1 В России можно купить OP470 в пластиковом корпусе примерно за 330р в Платане.
2 Cписок модулей, которые не удалось улучшить заменой ОУ на OP470: Dark Energy, A-116, A-130, A-119, A-120, A-121
equivalent input noise voltage
Смотреть что такое «equivalent input noise voltage» в других словарях:
Noise temperature — In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce… … Wikipedia
Noise (electronics) — Electronic noise [1] is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal noise is… … Wikipedia
Equivalent noise resistance — In telecommunication, an equivalent noise resistance is a quantitative representation in resistance units of the spectral density of a noise voltage generator, given byR n = frac
Noise (audio) — Noise in audio, recording, and broadcast systems refers to the residual low level sound (usually hiss and hum) that is heard in quiet periods of a programme. In audio engineering, it can refer either to the acoustic noise from loudspeakers, or to … Wikipedia
Noise — This article is about noise as an unwanted phenomenon. For other uses, see Noise (disambiguation). NASA researchers at Glenn Research Center conducting tests on aircraft engine noise in 1967 In common use, the word noise means any unwanted … Wikipedia
Noise reduction — For sound proofing, see soundproofing. For scientific aspects of noise reduction of machinery and products, see noise control. Noise reduction is the process of removing noise from a signal. All recording devices, both analogue or digital, have… … Wikipedia
Voltage regulator tube — A voltage regulator tube (VR tube) is an electronic component used as a shunt regulator to hold a voltage constant at a pre determined level.Physically, these devices resemble vacuum tubes, but there are two main differences: * Their glass… … Wikipedia
Input impedance — The input impedance, load impedance, or external impedance of a circuit or electronic device is the Thévenin equivalent impedance looking into its input.In audio systemsGenerally in audio and hi fi, the input impedance of components is several… … Wikipedia
Electronic noise — is an unwanted signal characteristic of all electronic circuits. Depending on the circuit, the noise put out by electronic devices can vary greatly. This noise comes from many different electronic effects.Thermal noise and shot noise are inherent … Wikipedia
Signal-to-noise ratio — For signal to noise ratio in statistics, see Cohen s d. Signal to noise ratio (often abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise. It is defined… … Wikipedia
Current-to-voltage converter — In electronics, a transimpedance amplifier is an amplifier that converts current to voltage. Its input ideally has zero impedance, and the input signal is a current. Its output may have low impedance, or in high frequency applications, may be… … Wikipedia
equivalent input noise current
Смотреть что такое «equivalent input noise current» в других словарях:
Noise temperature — In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce… … Wikipedia
Noise (electronics) — Electronic noise [1] is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal noise is… … Wikipedia
Noise — This article is about noise as an unwanted phenomenon. For other uses, see Noise (disambiguation). NASA researchers at Glenn Research Center conducting tests on aircraft engine noise in 1967 In common use, the word noise means any unwanted … Wikipedia
Current mirror — A current mirror is a circuit designed to copy a current through one active device by controlling the current in another active device of a circuit, keeping the output current constant regardless of loading. The current being copied can be, and… … Wikipedia
Current-to-voltage converter — In electronics, a transimpedance amplifier is an amplifier that converts current to voltage. Its input ideally has zero impedance, and the input signal is a current. Its output may have low impedance, or in high frequency applications, may be… … Wikipedia
Electronic noise — is an unwanted signal characteristic of all electronic circuits. Depending on the circuit, the noise put out by electronic devices can vary greatly. This noise comes from many different electronic effects.Thermal noise and shot noise are inherent … Wikipedia
Image noise — Noise clearly visible in an image from a digital camera Image noise is random (not present in the object imaged) variation of brightness or color information in images, and is usually an aspect of electronic noise. It can be produced by the… … Wikipedia
Johnson–Nyquist noise — (thermal noise, Johnson noise, or Nyquist noise) is the electronic noise generated by the thermal agitation of the charge carriers (usually the electrons) inside an electrical conductor at equilibrium, which happens regardless of any applied… … Wikipedia
Shot noise — Photon noise simulation. Shot noise is a type of electronic noise that may be dominant when the finite number of particles that carry energy (such as electrons in an electronic circuit or photons in an optical device) is sufficiently small so… … Wikipedia
List of noise topics — This is a list of noise topics. Contents 1 Engineering and physics 2 Environmental 3 Noise reduction 4 Music … Wikipedia
Operational amplifier — A Signetics μa741 operational amplifier, one of the most successful op amps. An operational amplifier ( op amp ) is a DC coupled high gain electronic voltage amplifier with a differential input and, usually, a single ended output.[1] An op amp… … Wikipedia
equivalent input noise
Смотреть что такое «equivalent input noise» в других словарях:
Noise temperature — In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce… … Wikipedia
Noise (electronics) — Electronic noise [1] is a random fluctuation in an electrical signal, a characteristic of all electronic circuits. Noise generated by electronic devices varies greatly, as it can be produced by several different effects. Thermal noise is… … Wikipedia
Equivalent noise resistance — In telecommunication, an equivalent noise resistance is a quantitative representation in resistance units of the spectral density of a noise voltage generator, given byR n = frac
Noise figure — (NF) is a measure of degradation of the signal to noise ratio (SNR), caused by components in a radio frequency (RF) signal chain. The noise figure is defined as the ratio of the output noise power of a device to the portion thereof attributable… … Wikipedia
Noise shaping — is a technique typically used in digital audio, image, and video processing, usually in combination with dithering, as part of the process of quantization or bit depth reduction of a digital signal. Its purpose is to increase the apparent signal… … Wikipedia
Noise (audio) — Noise in audio, recording, and broadcast systems refers to the residual low level sound (usually hiss and hum) that is heard in quiet periods of a programme. In audio engineering, it can refer either to the acoustic noise from loudspeakers, or to … Wikipedia
Noise measurement — is carried out in various fields. In acoustics, it can be for the purpose of measuring environmental noise, or part of a test procedure using white noise, or some other specialised form of test signal. In electronics it relates to the sensitivity … Wikipedia
Noise — This article is about noise as an unwanted phenomenon. For other uses, see Noise (disambiguation). NASA researchers at Glenn Research Center conducting tests on aircraft engine noise in 1967 In common use, the word noise means any unwanted … Wikipedia
Noise (radio) — In radio reception, noise is the superposition of white noise (also called static ) and other disturbing influences on the signal, caused either by thermal noise and other electronic noise from receiver input circuits or by interference from… … Wikipedia
Noise reduction — For sound proofing, see soundproofing. For scientific aspects of noise reduction of machinery and products, see noise control. Noise reduction is the process of removing noise from a signal. All recording devices, both analogue or digital, have… … Wikipedia
Noise spectral density — In communications, noise spectral density No is the noise power per unit of bandwidth; that is, it is the power spectral density of the noise. It has dimension of power/frequency (see dimensional analysis), whose SI coherent unit is watts per… … Wikipedia