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 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. (Full article...)
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Rowhammer (also written as row hammer or RowHammer) is a computer security exploit that takes advantage of an unintended and undesirable side effect in dynamic random-access memory (DRAM) in which memory cells interact electrically between themselves by leaking their charges, possibly changing the contents of nearby memory rows that were not addressed in the original memory access. This circumvention of the isolation between DRAM memory cells results from the high cell density in modern DRAM, and can be triggered by specially crafted memory access patterns that rapidly activate the same memory rows numerous times.
Staggered tuning is a technique used in the design of multi-stage tuned amplifiers whereby each stage is tuned to a slightly different frequency. In comparison to synchronous tuning (where each stage is tuned identically) it produces a wider bandwidth at the expense of reduced gain. It also produces a sharper transition from the passband to the stopband. Both staggered tuning and synchronous tuning circuits are easier to tune and manufacture than many other filter types.
The function of stagger-tuned circuits can be expressed as a rational function and hence they can be designed to any of the major filter responses such as Butterworth and Chebyshev. The poles of the circuit are easy to manipulate to achieve the desired response because of the amplifier buffering between stages. (Full article...)
Figure 1. Waveguide slotted line Slotted lines are used for microwave measurements and consist of a movable probe inserted into a slot in a transmission line. They are used in conjunction with a microwave power source and usually, in keeping with their low-cost application, a low cost Schottky diode detector and VSWR meter rather than an expensive microwave power meter.
Slotted lines can measure standing waves, wavelength, and, with some calculation or plotting on Smith charts, a number of other parameters including reflection coefficient and electrical impedance. A precision variable attenuator is often incorporated in the test setup to improve accuracy. This is used to make level measurements, while the detector and VSWR meter are retained only to mark a reference point for the attenuator to be set to, thus eliminating entirely the detector and meter measurement errors. The parameter most commonly measured by a slotted line is SWR. This serves as a measure of the accuracy of the impedance match to the item under test. This is especially important for transmitting antennas and their feed lines; high standing wave ratio on a radio or TV antenna can distort the signal, increase transmission line loss and potentially damage components in the transmission path, possibly even the transmitter. (Full article...)
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The Revox B215 is a cassette deck manufactured by Studer from 1985 until around 1990. A professional version with different control layout and audio path electronics was manufactured concurrently as the Studer A721. A later improved version was marketed as the Revox B215S. Because it was expensive compared to other consumer models and had exceptionally good mechanical performance and durability, the B215 was used primarily by professional customers—radio stations, recording studios and real-time cassette duplicators.
The B215 used a proven, reliable four-motor tape transport derived from the earlier B710 model. The B215 differed from the B710 and competing decks of the period in having an unusual, computer-like control panel and elaborate automation performed by three Philipsmicrocontrollers. The deck was equipped with automatic tape calibration, microcontroller-assisted setting of recording levels, and non-volatile memory. (Full article...)
This approach is especially useful in the design of mechanical filters—these use mechanical devices to implement an electrical function. However, the technique can be used to solve purely mechanical problems, and can also be extended into other, unrelated, energy domains. Nowadays, analysis by analogy is a standard design tool wherever more than one energy domain is involved. It has the major advantage that the entire system can be represented in a unified, coherent way. Electrical analogies are particularly used by transducer designers, by their nature they cross energy domains, and in control systems, whose sensors and actuators will typically be domain-crossing transducers. A given system being represented by an electrical analogy may conceivably have no electrical parts at all. For this reason domain-neutral terminology is preferred when developing network diagrams for control systems. (Full article...)
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Foster's reactance theorem is an important theorem in the fields of electrical network analysis and synthesis. The theorem states that the reactance of a passive, lossless two-terminal (one-port) network always strictly monotonically increases with frequency. It is easily seen that the reactances of inductors and capacitors individually increase or decrease with frequency respectively and from that basis a proof for passive lossless networks generally can be constructed. The proof of the theorem was presented by Ronald Martin Foster in 1924, although the principle had been published earlier by Foster's colleagues at American Telephone & Telegraph.
The theorem can be extended to admittances and the encompassing concept of immittances. A consequence of Foster's theorem is that zeros and poles of the reactance must alternate with frequency. Foster used this property to develop two canonical forms for realising these networks. Foster's work was an important starting point for the development of network synthesis. (Full article...)
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The first-generation iPad (/ˈaɪpæd/; EYE-pad) (retrospectively referred to unofficially as the iPad 1 or original iPad) is a tablet computer designed and marketed by Apple Inc. as the first device in the iPad lineup of tablet computers. It features an Apple A4SoC, a 9.7 in (250 mm) touchscreen display, and, on certain variants, the capability of accessing cellular networks. Using the iOS operating system, the iPad can play music, send and receive emails and browse the web. Other functions, which include the ability to play games and access references, GPS navigation software and social network services, can be enabled by downloading apps.
The device was announced and unveiled on January 27, 2010, by Steve Jobs, Apple's CEO, at an Apple press event. On April 3, 2010, the Wi-Fi variant of the device was released in the United States, followed by the release of the "Wi-Fi + 3G" variant on April 30. On May 28, 2010, it was released in Australia, Canada, France, Japan, Italy, Germany, Spain, Switzerland and the United Kingdom. (Full article...)
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The impedance analogy is a method of representing a mechanical system by an analogous electrical system. The advantage of doing this is that there is a large body of theory and analysis techniques concerning complex electrical systems, especially in the field of filters. By converting to an electrical representation, these tools in the electrical domain can be directly applied to a mechanical system without modification. A further advantage occurs in electromechanical systems: Converting the mechanical part of such a system into the electrical domain allows the entire system to be analysed as a unified whole.
The mathematical behaviour of the simulated electrical system is identical to the mathematical behaviour of the represented mechanical system. Each element in the electrical domain has a corresponding element in the mechanical domain with an analogous constitutive equation. All laws of circuit analysis, such as Kirchhoff's circuit laws, that apply in the electrical domain also apply to the mechanical impedance analogy. (Full article...)
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The Linn Isobarik DMS (with in-built crossover) in a domestic setting The Linn Isobarik, nicknamed "Bariks" or "Briks", is a loudspeaker designed and manufactured by Linn Products. The Isobarik is known for both its reproduction of low bass frequencies and being very demanding on amplifiers.
Launched in 1973, the Isobarik DMS, Linn's maiden and flagship loudspeaker was based on and named for the isobaric loading principle invented in the 1950s. The speaker exists also as the Isobarik PMS – destined for the professional market. Although discontinued in 1992, it remains popular among audiophiles. (Full article...)
The actual impedance may vary quite considerably from the nominal figure with changes in frequency. In the case of cables and other transmission lines, there is also variation along the length of the cable, if it is not properly terminated. (Full article...)
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Telephone cable containing multiple twisted-pair lines The primary line constants are parameters that describe the characteristics of conductive transmission lines, such as pairs of copper wires, in terms of the physical electrical properties of the line. The primary line constants are only relevant to transmission lines and are to be contrasted with the secondary line constants, which can be derived from them, and are more generally applicable. The secondary line constants can be used, for instance, to compare the characteristics of a waveguide to a copper line, whereas the primary constants have no meaning for a waveguide.
The constants are conductor resistance and inductance, and insulator capacitance and conductance, which are by convention given the symbols R, L, C, and G respectively. The constants are enumerated in terms of per unit length. The circuit representation of these elements requires a distributed-element model and consequently calculus must be used to analyse the circuit. The analysis yields a system of two first order, simultaneous linear partial differential equations which may be combined to derive the secondary constants of characteristic impedance and propagation constant. (Full article...)
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The Nakamichi Dragon is an audio cassette deck that was introduced by Nakamichi in 1982 and marketed until 1994. The Dragon was the first Nakamichi model with bidirectional replay capability and the world's first production tape recorder with an automatic azimuth correction system; this feature, which was invented by Philips engineers and improved by Niro Nakamichi, continuously adjusts the azimuth of the replay head to minimize apparent head skew and correctly reproduce the treble signal present on the tape. The system allows the correct reproduction of mechanically skewed cassettes and recordings made on misaligned decks. Apart from the Dragon, similar systems have only been used in the Nakamichi TD-1200 car cassette player and the Marantz SD-930 cassette deck.
At the time of its introduction, the Dragon had the lowest-ever wow and flutter and the highest-ever dynamic range, losing marginally to the former Nakamichi flagship the 1000ZXL in frequency response. Competing models by Sony, Studer, Tandberg and TEAC that were introduced later in the 1980s sometimes surpassed the Dragon in mechanical quality and feature set but none could deliver the same mix of sound quality, flexibility and technological advancement. The Dragon, despite inherent issues with long-term reliability, remained the highest point of compact cassette technology. (Full article...)
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A time-domain reflectometer; an instrument used to locate the position of faults on lines from the time taken for a reflected wave to return from the discontinuity. A signal travelling along an electrical transmission line will be partly, or wholly, reflected back in the opposite direction when the travelling signal encounters a discontinuity in the characteristic impedance of the line, or if the far end of the line is not terminated in its characteristic impedance. This can happen, for instance, if two lengths of dissimilar transmission lines are joined.
This article is about signal reflections on electrically conducting lines. Such lines are loosely referred to as copper lines, and indeed, in telecommunications are generally made from copper, but other metals are used, notably aluminium in power lines. Although this article is limited to describing reflections on conducting lines, this is essentially the same phenomenon as optical reflections in fibre-optic lines and microwave reflections in waveguides. (Full article...)
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Air stripline is a form of electrical planar transmission line whereby a conductor in the form of a thin metal strip is suspended between two ground planes. The idea is to make the dielectric essentially air. Mechanical support of the line may be a thin substrate, periodical insulated supports, or the device connectors and other electrical items.
Air stripline is most commonly used at microwave frequencies, especially in the C band. Its advantage over standard stripline and other planar technologies is that its air dielectric avoids dielectric loss. Many useful circuits can be constructed with air stripline and it is also easier to achieve strong coupling between components in this technology than with other planar formats. It was invented by Robert M. Barrett in the 1950s. (Full article...)
Carl Friedrich Gauss (Gauß) (30 April 1777 – 23 February 1855) was a Germanmathematician and scientist of profound genius who contributed significantly to many fields, including number theory, analysis, differential geometry, geodesy, magnetism, astronomy and optics. Sometimes known as "the prince of mathematicians" and "greatest mathematician since antiquity", Gauss had a remarkable influence in many fields of mathematics and science and is ranked as one of history's most influential mathematicians. Gauss was a child prodigy, and made his first ground-breaking mathematical discoveries while still a teenager. The cgsunit for magnetic induction was named gauss in his honor.
Early development was prompted by a 1936 memo from Henry Tizard on the topic of night fighting. The memo was sent to Robert Watson-Watt, director of the radar research efforts, who agreed to allow physicist Edward George "Taffy" Bowen to form a team to study the problem of air interception. The team had a test bed system in flights later that year, but progress was delayed for four years by emergency relocations, three abandoned production designs and Bowen's increasingly adversarial relationship with Watt's replacement, Albert Rowe. Ultimately, Bowen was forced from the team just as the system was finally maturing. (Full article...)
... that in 2019, Chinese electronics company Xiaomi posted a video of their third-quarterly financial report featuring a parody of the anime song "Renai Circulation"?
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