Misplaced Pages

#53946

62-463: In electronics , a digital-to-analog converter ( DAC , D/A , D2A , or D-to-A ) is a system that converts a digital signal into an analog signal . An analog-to-digital converter (ADC) performs the reverse function. There are several DAC architectures ; the suitability of a DAC for a particular application is determined by figures of merit including: resolution , maximum sampling frequency and others. Digital-to-analog conversion can degrade

124-432: A mass-production basis, which limited them to a number of specialised applications. The MOSFET was invented at Bell Labs between 1955 and 1960. It was the first truly compact transistor that could be miniaturised and mass-produced for a wide range of uses. Its advantages include high scalability , affordability, low power consumption, and high density . It revolutionized the electronics industry , becoming

186-403: A radio antenna , practicable. Vacuum tubes (thermionic valves) were the first active electronic components which controlled current flow by influencing the flow of individual electrons , and enabled the construction of equipment that used current amplification and rectification to give us radio , television , radar , long-distance telephony and much more. The early growth of electronics

248-491: A transformerless output stage , the devices are essentially in series with the power supply and output load (such as a loudspeaker), possibly via some large capacitor and/or small resistances. For some years following the introduction of solid-state amplifiers, their perceived sound did not have the excellent audio quality of the best valve amplifiers (see valve audio amplifier ). This led audiophiles to believe that "tube sound" or valve sound had an intrinsic quality due to

310-439: A whiffletree mechanism to produce finer steps. The IBM Selectric typewriter uses such a system. DACs are widely used in modern communication systems enabling the generation of digitally-defined transmission signals. High-speed DACs are used for mobile communications and ultra-high-speed DACs are employed in optical communications systems. The most common types of electronic DACs are: The most important characteristics of

372-401: A DAC are: Other measurements, such as phase distortion and jitter , can also be very important for some applications, some of which (e.g. wireless data transmission, composite video) may even rely on accurate production of phase-adjusted signals. Non-linear PCM encodings (A-law / μ-law, ADPCM, NICAM) attempt to improve their effective dynamic ranges by using logarithmic step sizes between

434-528: A continually varying physical signal . Provided that a signal's bandwidth meets the requirements of the Nyquist–;Shannon sampling theorem (i.e., a baseband signal with bandwidth less than the Nyquist frequency ) and was sampled with infinite resolution, the original signal can theoretically be reconstructed from the sampled data. However, an ADC's filtering can't entirely eliminate all frequencies above

496-418: A leading role in the field of microwave and high power transmission as well as television receivers until the middle of the 1980s. Since then, solid-state devices have all but completely taken over. Vacuum tubes are still used in some specialist applications such as high power RF amplifiers , cathode-ray tubes , specialist audio equipment, guitar amplifiers and some microwave devices . In April 1955,

558-676: A linear contrast ratio (difference between darkest and brightest output levels) of 1000:1 or greater, equivalent to 10 bits of audio precision even though it may only accept signals with 8-bit precision and use an LCD panel that only represents 6 or 7 bits per channel. Video signals from a digital source, such as a computer, must be converted to analog form if they are to be displayed on an analog monitor. As of 2007, analog inputs were more commonly used than digital, but this changed as flat-panel displays with DVI and/or HDMI connections became more widespread. A video DAC is, however, incorporated in any digital video player with analog outputs. The DAC

620-477: A minority continue to use tube preamps, tube power amps and tube effects units . While hi-fi enthusiasts and audio engineers doing live sound or monitoring tracks in the studio typically seek out amplifiers with the lowest distortion, electric instrument players in genres such as blues , rock music and heavy metal music , among others, use tube amplifiers because they like the natural overdrive that tube amps produce when pushed hard. The Class-D amplifier , which

682-566: A mix of the two types. Analog circuits are becoming less common, as many of their functions are being digitized. Analog circuits use a continuous range of voltage or current for signal processing, as opposed to the discrete levels used in digital circuits. Analog circuits were common throughout an electronic device in the early years in devices such as radio receivers and transmitters. Analog electronic computers were valuable for solving problems with continuous variables until digital processing advanced. As semiconductor technology developed, many of

SECTION 10

#1732858152054

744-468: A packaged IC) would typically be extremely high-speed low-resolution power-hungry types, as used in military radar systems. Very high-speed test equipment, especially sampling oscilloscopes , may also use discrete DACs. A DAC converts an abstract finite-precision number (usually a fixed-point binary number ) into a physical quantity (e.g., a voltage or a pressure ). In particular, DACs are often used to convert finite-precision time series data to

806-540: A physical space, although in more recent years the trend has been towards electronics lab simulation software , such as CircuitLogix , Multisim , and PSpice . Today's electronics engineers have the ability to design circuits using premanufactured building blocks such as power supplies , semiconductors (i.e. semiconductor devices, such as transistors), and integrated circuits. Electronic design automation software programs include schematic capture programs and printed circuit board design programs. Popular names in

868-442: A power amplifier mounted in a 19" road case . Power amplifiers are available in standalone units, which are used by hi-fi audio enthusiasts and designers of public address systems (PA systems) and sound reinforcement systems . A hi-fi user of power amplifiers may have a stereo power amplifier to drive left and right speakers and a single-channel (mono) power amplifier to drive a subwoofer . The number of power amplifiers used in

930-420: A signal, so a DAC should be specified that has insignificant errors in terms of the application. DACs are commonly used in music players to convert digital data streams into analog audio signals . They are also used in televisions and mobile phones to convert digital video data into analog video signals . These two applications use DACs at opposite ends of the frequency/resolution trade-off. The audio DAC

992-623: A sound reinforcement setting depends on the size of the venue. A small coffeehouse may have a single power amp driving two PA speakers. A nightclub may have several power amps for the main speakers, one or more power amps for the monitor speakers (pointing towards the band) and an additional power amp for the subwoofer. A stadium concert may have a large number of power amps mounted in racks. Most consumer electronics sound products, such as TVs , boom boxes , home cinema sound systems, Casio and Yamaha electronic keyboards , "combo" guitar amps and car stereos have power amplifiers integrated inside

1054-490: A type of power MOSFET. Hitachi was the only LDMOS manufacturer between 1977 and 1983, during which time LDMOS was used in audio power amplifiers from manufacturers such as HH Electronics (V-series) and Ashly Audio , and were used for music and public address systems . Class-D amplifiers became successful in the mid-1980s when low-cost, fast-switching MOSFETs were made available. Many transistor amps use MOSFET devices in their power sections, because their distortion curve

1116-401: A volume control and source selector. One alternative to a separate preamp is to simply use passive volume and switching controls, sometimes integrated into a power amplifier to form an integrated amplifier . The final stage of amplification, after preamplifiers, is the output stage, where the highest demands are placed on the transistors or tubes. For this reason, the design choices made around

1178-524: Is a low-frequency, high-resolution type while the video DAC is a high-frequency low- to medium-resolution type. Due to the complexity and the need for precisely matched components , all but the most specialized DACs are implemented as integrated circuits (ICs). These typically take the form of metal–oxide–semiconductor (MOS) mixed-signal integrated circuit chips that integrate both analog and digital circuits . Discrete DACs (circuits constructed from multiple discrete electronic components instead of

1240-548: Is defined as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit. Noise is associated with all electronic circuits. Noise may be electromagnetically or thermally generated, which can be decreased by lowering the operating temperature of the circuit. Other types of noise, such as shot noise cannot be removed as they are due to limitations in physical properties. Many different methods of connecting components have been used over

1302-606: Is more tube-like . In the 2010s, there are still audio enthusiasts, musicians (particularly electric guitarists , electric bassists , Hammond organ players and Fender Rhodes electric piano players, among others), audio engineers and music producers who prefer tube-based amplifiers, and what is perceived as a "warmer" tube sound . Key design parameters for audio power amplifiers are frequency response , gain , noise , and distortion . These are interdependent; increasing gain often leads to undesirable increases in noise and distortion. While negative feedback actually reduces

SECTION 20

#1732858152054

1364-422: Is much more efficient than Class AB amplifiers, is now widely used in consumer electronics audio products, bass amplifiers and sound reinforcement system gear, as Class-D amplifiers are much lighter in weight and produce much less heat. Since modern digital devices, including CD and DVD players, radio receivers and tape decks already provide a "flat" signal at line level, the preamp is not needed other than as

1426-504: Is the semiconductor industry , which in response to global demand continually produces ever-more sophisticated electronic devices and circuits. The semiconductor industry is one of the largest and most profitable sectors in the global economy, with annual revenues exceeding $ 481 billion in 2018. The electronics industry also encompasses other sectors that rely on electronic devices and systems, such as e-commerce, which generated over $ 29 trillion in online sales in 2017. The identification of

1488-595: Is the voltage comparator which receives a continuous range of voltage but only outputs one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch , having essentially two levels of output. Analog circuits are still widely used for signal amplification, such as in the entertainment industry, and conditioning signals from analog sensors, such as in industrial measurement and control. Digital circuits are electric circuits based on discrete voltage levels. Digital circuits use Boolean algebra and are

1550-403: Is then reconstructed into analog using a DAC on the receiving party's end. Video sampling tends to work on a completely different scale altogether thanks to the highly nonlinear response both of cathode ray tubes (for which the vast majority of digital video foundation work was targeted) and the human eye, using a "gamma curve" to provide an appearance of evenly distributed brightness steps across

1612-448: Is therefore the process of defining and developing complex electronic devices to satisfy specified requirements of the user. Due to the complex nature of electronics theory, laboratory experimentation is an important part of the development of electronic devices. These experiments are used to test or verify the engineer's design and detect errors. Historically, electronics labs have consisted of electronics devices and equipment located in

1674-510: Is usually integrated with some memory ( RAM ), which contains conversion tables for gamma correction , contrast and brightness, to make a device called a RAMDAC . A device that is distantly related to the DAC is the digitally controlled potentiometer , used to control an analog signal digitally. A one-bit mechanical actuator assumes two positions: one when on, another when off. The motion of several one-bit actuators can be combined and weighted with

1736-621: The IBM 608 was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the first all-transistorized calculator to be manufactured for the commercial market. The 608 contained more than 3,000 germanium transistors. Thomas J. Watson Jr. ordered all future IBM products to use transistors in their design. From that time on transistors were almost exclusively used for computer logic circuits and peripheral devices. However, early junction transistors were relatively bulky devices that were difficult to manufacture on

1798-566: The Williamson amplifier of 1947–9). Audio power amplifiers based on transistors became practical with the wide availability of inexpensive transistors in the late 1960s. Since the 1970s, most modern audio amplifiers are based on solid-state transistors, especially the bipolar junction transistor (BJT) and the metal–oxide–semiconductor field-effect transistor (MOSFET). Transistor-based amplifiers are lighter in weight, more reliable and require less maintenance than tube amplifiers . The MOSFET

1860-408: The digital revolution . To illustrate, consider a typical long-distance telephone call. The caller's voice is converted into an analog electrical signal by a microphone , then the analog signal is converted to a digital stream by an ADC. The digital stream is then divided into network packets where it may be sent along with other digital data , not necessarily audio. The packets are then received at

1922-459: The electron in 1897 by Sir Joseph John Thomson , along with the subsequent invention of the vacuum tube which could amplify and rectify small electrical signals , inaugurated the field of electronics and the electron age. Practical applications started with the invention of the diode by Ambrose Fleming and the triode by Lee De Forest in the early 1900s, which made the detection of small electrical voltages, such as radio signals from

Digital-to-analog converter - Misplaced Pages Continue

1984-399: The hi-fi audiophile market (a niche market) of audio enthusiasts and sound reinforcement system professionals, many consumer electronics audio products such as an integrated amplifier , a receiver , clock radios, boomboxes and televisions have both a preamplifier and a power amplifier contained in a single chassis. The audio amplifier was invented around 1912 by Lee de Forest . This

2046-448: The 1960s, U.S. manufacturers were unable to compete with Japanese companies such as Sony and Hitachi who could produce high-quality goods at lower prices. By the 1980s, however, U.S. manufacturers became the world leaders in semiconductor development and assembly. However, during the 1990s and subsequently, the industry shifted overwhelmingly to East Asia (a process begun with the initial movement of microchip mass-production there in

2108-531: The 1970s), as plentiful, cheap labor, and increasing technological sophistication, became widely available there. Over three decades, the United States' global share of semiconductor manufacturing capacity fell, from 37% in 1990, to 12% in 2022. America's pre-eminent semiconductor manufacturer, Intel Corporation , fell far behind its subcontractor Taiwan Semiconductor Manufacturing Company (TSMC) in manufacturing technology. By that time, Taiwan had become

2170-709: The EDA software world are NI Multisim, Cadence ( ORCAD ), EAGLE PCB and Schematic, Mentor (PADS PCB and LOGIC Schematic), Altium (Protel), LabCentre Electronics (Proteus), gEDA , KiCad and many others. Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Heat dissipation is mostly achieved by passive conduction/convection. Means to achieve greater dissipation include heat sinks and fans for air cooling, and other forms of computer cooling such as water cooling . These techniques use convection , conduction , and radiation of heat energy . Electronic noise

2232-546: The Nyquist frequency, which will alias into the baseband frequency range. And the ADC's digital sampling process introduces some quantization error (rounding error), which manifests as low-level noise. These errors can be kept within the requirements of the targeted application (e.g. under the limited dynamic range of human hearing for audio applications). DACs and ADCs are part of an enabling technology that has contributed greatly to

2294-409: The basis of all digital computers and microprocessor devices. They range from simple logic gates to large integrated circuits, employing millions of such gates. Digital circuits use a binary system with two voltage levels labelled "0" and "1" to indicated logical status. Often logic "0" will be a lower voltage and referred to as "Low" while logic "1" is referred to as "High". However, some systems use

2356-459: The circuit, thus slowing the computer. The invention of the integrated circuit by Jack Kilby and Robert Noyce solved this problem by making all the components and the chip out of the same block (monolith) of semiconductor material. The circuits could be made smaller, and the manufacturing process could be automated. This led to the idea of integrating all components on a single-crystal silicon wafer, which led to small-scale integration (SSI) in

2418-531: The concept of comparing the ratio between the input distortion and the output distortion of an amplifier. This new idea helped audio design engineers to better evaluate the distortion processes within an amplifier. Important applications include public address systems, theatrical and concert sound reinforcement systems , and domestic systems such as a stereo or home-theatre system . Instrument amplifiers including guitar amplifiers and electric keyboard amplifiers also use audio power amplifiers. In some cases,

2480-803: The destination, but each packet may take a completely different route and may not even arrive at the destination in the correct time order. The digital voice data is then extracted from the packets and assembled into a digital data stream. A DAC converts this back into an analog electrical signal, which drives an audio amplifier , which in turn drives a speaker , which finally produces sound. Most modern audio signals are stored in digital form (for example MP3s and CDs ), and in order to be heard through speakers, they must be converted into an analog signal. DACs are therefore found in CD players , digital music players , and PC sound cards . Specialist standalone DACs can also be found in high-end hi-fi systems. These normally take

2542-492: The digital output of a compatible CD player or dedicated transport (which is basically a CD player with no internal DAC) and convert the signal into an analog line-level output that can then be fed into an amplifier to drive speakers. Similar digital-to-analog converters can be found in digital speakers such as USB speakers, and in sound cards . In voice over IP applications, the source must first be digitized for transmission, so it undergoes conversion via an ADC and

Digital-to-analog converter - Misplaced Pages Continue

2604-442: The display's full dynamic range - hence the need to use RAMDACs in computer video applications with deep enough color resolution to make engineering a hardcoded value into the DAC for each output level of each channel impractical (e.g. an Atari ST or Sega Genesis would require 24 such values; a 24-bit video card would need 768...). Given this inherent distortion, it is not unusual for a television or video projector to truthfully claim

2666-874: The early 1960s, and then medium-scale integration (MSI) in the late 1960s, followed by VLSI . In 2008, billion-transistor processors became commercially available. An electronic component is any component in an electronic system either active or passive. Components are connected together, usually by being soldered to a printed circuit board (PCB), to create an electronic circuit with a particular function. Components may be packaged singly, or in more complex groups as integrated circuits . Passive electronic components are capacitors , inductors , resistors , whilst active components are such as semiconductor devices; transistors and thyristors , which control current flow at electron level. Electronic circuit functions can be divided into two function groups: analog and digital. A particular device may consist of circuitry that has either or

2728-452: The electronic logic gates to generate binary states. Highly integrated devices: Electronic systems design deals with the multi-disciplinary design issues of complex electronic devices and systems, such as mobile phones and computers . The subject covers a broad spectrum, from the design and development of an electronic system ( new product development ) to assuring its proper function, service life and disposal . Electronic systems design

2790-562: The following ways: The electronics industry consists of various sectors. The central driving force behind the entire electronics industry is the semiconductor industry sector, which has annual sales of over $ 481 billion as of 2018. The largest industry sector is e-commerce , which generated over $ 29 trillion in 2017. The most widely manufactured electronic device is the metal-oxide-semiconductor field-effect transistor (MOSFET), with an estimated 13   sextillion MOSFETs having been manufactured between 1960 and 2018. In

2852-489: The functions of analog circuits were taken over by digital circuits, and modern circuits that are entirely analog are less common; their functions being replaced by hybrid approach which, for instance, uses analog circuits at the front end of a device receiving an analog signal, and then use digital processing using microprocessor techniques thereafter. Sometimes it may be difficult to classify some circuits that have elements of both linear and non-linear operation. An example

2914-630: The gain, it also reduces distortion. Most audio amplifiers are linear amplifiers operating in class AB . Until the 1970s, most amplifiers used vacuum tubes . During the 1970s, tube amps were increasingly replaced with transistor -based amplifiers, which were lighter in weight, more reliable, and lower maintenance. Nevertheless, tube preamplifiers are still sold in niche markets , such as with home hi-fi enthusiasts, audio engineers and music producers (who use tube preamplifiers in studio recordings to "warm up" microphone signals) and electric guitarists, electric bassists and Hammond organ players, of whom

2976-498: The input signal to an audio power amplifier, such as the signal from an electric guitar, may measure only a few hundred microwatts , its output may be a few watts for small consumer electronics devices, such as clock radios , tens or hundreds of watts for a home stereo system , several thousand watts for a nightclub 's sound system or tens of thousands of watts for a large rock concert sound reinforcement system. While power amplifiers are available in standalone units, typically aimed at

3038-399: The most widely used electronic device in the world. The MOSFET is the basic element in most modern electronic equipment. As the complexity of circuits grew, problems arose. One problem was the size of the circuit. A complex circuit like a computer was dependent on speed. If the components were large, the wires interconnecting them must be long. The electric signals took time to go through

3100-618: The output device (for single-ended output stages, such as in single-ended triode amplifiers) or devices (for push-pull output stages), such as the Class of operation of the output devices is often taken as the description of the whole power amplifier. For example, a Class B amplifier will probably have just the high power output devices operating cut off for half of each cycle, while the other devices (such as differential amplifier, voltage amplifier and possibly even driver transistors) operate in Class A. In

3162-429: The output signal strengths represented by each data bit. This trades greater quantization distortion of loud signals for better performance of quiet signals. Electronics Electronic devices have hugely influenced the development of many aspects of modern society, such as telecommunications , entertainment, education, health care, industry, and security. The main driving force behind the advancement of electronics

SECTION 50

#1732858152054

3224-422: The power amplifier for an instrument amplifier is integrated into a single amplifier "head" which contains a preamplifier, tone controls, and electronic effects. These components may be mounted in a wooden speaker cabinet to create a "combo amplifier". Musicians with unique performance needs and/or a need for very powerful amplification may create a custom setup with separate rackmount preamplifiers, equalizers, and

3286-540: The reverse definition ("0" is "High") or are current based. Quite often the logic designer may reverse these definitions from one circuit to the next as they see fit to facilitate their design. The definition of the levels as "0" or "1" is arbitrary. Ternary (with three states) logic has been studied, and some prototype computers made, but have not gained any significant practical acceptance. Universally, Computers and Digital signal processors are constructed with digital circuits using Transistors such as MOSFETs in

3348-416: The signal from a radio receiver or an electric guitar pickup , to a level that is high enough for driving loudspeakers or headphones . Audio power amplifiers are found in all manner of sound systems including sound reinforcement , public address , home audio systems and musical instrument amplifiers like guitar amplifiers . It is the final electronic stage in a typical audio playback chain before

3410-447: The signal is sent to the loudspeakers. The preceding stages in such a chain are low-power audio amplifiers which perform tasks like pre-amplification of the signal, equalization , mixing different input signals . The inputs can also be any number of audio sources like record players , CD players , digital audio players and cassette players . Most audio power amplifiers require these low-level inputs, which are line level . While

3472-537: The solution for TIM distortion, including increasing slew rate , decreasing preamp frequency bandwidth, and the insertion of a lag compensation circuit in the input stage of the amplifier. In high-quality modern amplifiers the open loop response is at least 20 kHz, canceling TIM distortion. The next step in advanced design was the Baxandall Theorem, created by Peter Baxandall in England. This theorem introduced

3534-604: The vacuum tube technology itself. In 1970, Matti Otala published a paper on the origin of a previously unobserved form of distortion: transient intermodulation distortion (TIM), later also called slew-induced distortion (SID) by others. TIM distortion was found to occur during very rapid increases in amplifier output voltage. TIM did not appear at steady state sine tone measurements, helping to hide it from design engineers prior to 1970. Problems with TIM distortion stem from reduced open loop frequency response of solid-state amplifiers. Further works of Otala and other authors found

3596-641: The world's leading source of advanced semiconductors —followed by South Korea , the United States , Japan , Singapore , and China . Important semiconductor industry facilities (which often are subsidiaries of a leading producer based elsewhere) also exist in Europe (notably the Netherlands ), Southeast Asia, South America, and Israel . Audio amplifier An audio power amplifier (or power amp ) amplifies low-power electronic audio signals , such as

3658-756: The years. For instance, early electronics often used point to point wiring with components attached to wooden breadboards to construct circuits. Cordwood construction and wire wrap were other methods used. Most modern day electronics now use printed circuit boards made of materials such as FR4 , or the cheaper (and less hard-wearing) Synthetic Resin Bonded Paper ( SRBP , also known as Paxoline/Paxolin (trade marks) and FR2) – characterised by its brown colour. Health and environmental concerns associated with electronics assembly have gained increased attention in recent years, especially for products destined to go to European markets. Electrical components are generally mounted in

3720-471: Was invented at Bell Labs between 1955 and 1960. was adapted into a power MOSFET for audio by Jun-ichi Nishizawa at Tohoku University in 1974. Power MOSFETs were soon manufactured by Yamaha for their hi-fi audio amplifiers. JVC , Pioneer Corporation , Sony and Toshiba also began manufacturing amplifiers with power MOSFETs in 1974. In 1977, Hitachi introduced the LDMOS (lateral diffused MOS),

3782-536: Was made possible by his invention of the first practical amplifying electrical component, the triode vacuum tube (or "valve" in British English) in 1907. The triode was a three-terminal device with a control grid that can modulate the flow of electrons from the filament to the plate. The triode vacuum amplifier was used to make the first AM radio . Early audio power amplifiers were based on vacuum tubes and some of these achieved notably high audio quality (e.g.,

SECTION 60

#1732858152054

3844-484: Was rapid, and by the 1920s, commercial radio broadcasting and telecommunications were becoming widespread and electronic amplifiers were being used in such diverse applications as long-distance telephony and the music recording industry. The next big technological step took several decades to appear, when the first working point-contact transistor was invented by John Bardeen and Walter Houser Brattain at Bell Labs in 1947. However, vacuum tubes continued to play

#53946