A pickup is a transducer that captures or senses mechanical vibrations produced by musical instruments stringed instruments such as the electric guitar, converts these to an electrical signal, amplified using an instrument amplifier to produce musical sounds through a loudspeaker in a speaker enclosure. The signal from a pickup can be recorded directly. Most electric guitars and electric basses use magnetic pickups. Acoustic guitars, upright basses and fiddles use a piezoelectric pickup. A typical magnetic pickup is a transducer that consists of one or more permanent magnets wrapped with a coil of several thousand turns of fine enameled copper wire; the magnet creates a magnetic field, focused by the pickup's pole piece or pieces. The permanent magnet in the pickup magnetises the guitar string above it. So the string is, in essence, a magnet itself and its magnetic field is in alignment with that of the permanent magnet that magnetized it; when the string is plucked, the magnetic field around it moves down with the string.
This moving magnetic field induces a current in the coil of the pickup. The pickup is connected with a patch cable to an amplifier, which amplifies the signal to a sufficient magnitude of power to drive a loudspeaker. A pickup can be connected to recording equipment via a patch cable; the pickup is most mounted on the body of the instrument, but can be attached to the bridge, neck or pickguard. Pickups have magnetic polepieces centered on each string. On most guitars, the strings are not parallel: they converge at the nut and diverge at the bridge. Thus, bridge and middle pickups have different polepiece spacings on the same guitar. There are string spacing between the poles. Spacing is measured either as a distance between 1st to 6th polepieces' centers, or as a distance between adjacent polepieces' centers; some high-output pickups employ strong magnets, thus creating more flux and thereby more output. This can be detrimental to the final sound because the magnet's pull on the strings can cause problems with intonation as well as damp the strings and reduce sustain.
Other high-output pickups have more turns of wire to increase the voltage generated by the string's movement. However, this increases the pickup's output resistance/impedance, which can affect high frequencies if the pickup is not isolated by a buffer amplifier or a DI unit; the turns of wire in proximity to each other have an equivalent self-capacitance that, when added to any cable capacitance present, resonates with the inductance of the winding. This resonance can accentuate certain frequencies; the more turns of wire in the winding, the higher the output voltage but the lower this resonance frequency. The inductive source impedance inherent in this type of transducer makes it less linear than other forms of pickups, such as piezo-electric or optical; the external load consists of resistance and capacitance between the hot lead and shield in the guitar cable. The electric cable has a capacitance, which can be a significant portion of the overall system capacitance; this arrangement of passive components forms a resistively-damped second-order low-pass filter.
Pickups are designed to feed a high input impedance a megohm or more, a low-impedance load reduces the high-frequency response of the pickup because of the filtering effect of the inductance. Single-coil pickups act like a directional antenna and are prone to pick up mains hum — nuisance alternating current electromagnetic interference from electrical power cables, power transformers, fluorescent light ballasts, video monitors or televisions — along with the musical signal. Mains hum consists of a fundamental signal at a nominal 50 or 60 Hz, depending on local current frequency, some harmonic content. To overcome this, the humbucking pickup was invented by Joseph Raymond "Ray" Butts, but Seth Lover of Gibson was working on one. Who developed it first is a matter of some debate, but Ray Butts was awarded the first patent and Seth Lover came next. A humbucking pickup is composed of two coils; each set of six magnetic poles is opposite in polarity. Since ambient hum from electrical devices reaches the coils as common-mode noise, it induces an equal voltage in each coil, but 180 degrees out of phase between the two voltages.
These cancel each other, while the signal from the guitar string is doubled. When wired in series, as is most common, the overall inductance of the pickup is increased, which lowers its resonance frequency and attenuates the higher frequencies, giving a less trebly tone than either of the two component single-coil pickups would give alone. An alternative wiring places the coils in buck parallel, which has a more neutral effect on resonant frequency; this pickup wiring is rare, as guitarists have come to expect that humbucking pickups'have a sound', are not so neutral. On fine jazz guitars, the parallel wiring produces cleaner sound, as the lowered source impedance drives capacitive cable with lower high frequency attenuation. A side-by-side humbucking pickup senses a wider section of each strin
Pseudocode is an informal high-level description of the operating principle of a computer program or other algorithm. It uses the structural conventions of a normal programming language, but is intended for human reading rather than machine reading. Pseudocode omits details that are essential for machine understanding of the algorithm, such as variable declarations, system-specific code and some subroutines; the programming language is augmented with natural language description details, where convenient, or with compact mathematical notation. The purpose of using pseudocode is that it is easier for people to understand than conventional programming language code, that it is an efficient and environment-independent description of the key principles of an algorithm, it is used in textbooks and scientific publications that are documenting various algorithms, in planning of computer program development, for sketching out the structure of the program before the actual coding takes place. No standard for pseudocode syntax exists.
Pseudocode resembles skeleton programs. Flowcharts, drakon-charts and Unified Modeling Language charts can be thought of as a graphical alternative to pseudocode, but are more spacious on paper. Languages such as HAGGIS bridge the gap between pseudocode and code written in programming languages. Textbooks and scientific publications related to computer science and numerical computation use pseudocode in description of algorithms, so that all programmers can understand them if they do not all know the same programming languages. In textbooks, there is an accompanying introduction explaining the particular conventions in use; the level of detail of the pseudocode may in some cases approach that of formalized general-purpose languages. A programmer who needs to implement a specific algorithm an unfamiliar one, will start with a pseudocode description, "translate" that description into the target programming language and modify it to interact with the rest of the program. Programmers may start a project by sketching out the code in pseudocode on paper before writing it in its actual language, as a top-down structuring approach, with a process of steps to be followed as a refinement.
Pseudocode does not obey the syntax rules of any particular language. Some writers borrow style and syntax from control structures from some conventional programming language, although this is discouraged; some syntax sources include Fortran, Pascal, BASIC, C, C++, Lisp, ALGOL. Variable declarations are omitted. Function calls and blocks of code, such as code contained within a loop, are replaced by a one-line natural language sentence. Depending on the writer, pseudocode may therefore vary in style, from a near-exact imitation of a real programming language at one extreme, to a description approaching formatted prose at the other; this is an example of pseudocode: In numerical computation, pseudocode consists of mathematical notation from set and matrix theory, mixed with the control structures of a conventional programming language, also natural language descriptions. This is a compact and informal notation that can be understood by a wide range of mathematically trained people, is used as a way to describe mathematical algorithms.
For example, the sum operator or the product operator may represent a for-loop and a selection structure in one expression: Return ∑ k ∈ S x k Normally non-ASCII typesetting is used for the mathematical equations, for example by means of markup languages, such as TeX or MathML, or proprietary formula editors. Mathematical style pseudocode is sometimes referred to as pidgin code, for example pidgin ALGOL, pidgin Fortran, pidgin BASIC, pidgin Pascal, pidgin C, pidgin Lisp. Here follows a longer example of mathematical-style pseudocode, for the Ford–Fulkerson algorithm: algorithm ford-fulkerson is input: Graph G with flow capacity c, source node s, sink node t output: Flow f such that f is maximal from s to t for each edge in GE do f ← 0 f ← 0 while there exists a path p from s to t in the residual network Gf do let cf be the flow capacity of the residual network Gf cf ← min for each edge in p do f ← f + cf f ← −f return f Various attempts to bring elements of natural language grammar into computer programming have produced programming languages such as HyperTalk, AppleScript, SQL, Inform and to some extent Python.
In these languages and other special characters are replaced by prepositions, resulting in quite talkative code. These languages are dynamically typed, meaning that variable declarations and other boilerplate code can be omitted; such languages may make it easier for a person without knowledge about the language to understand the code and also to learn the language. However, the similarity to natural language is more cosmetic than genuine; the syntax rules may be just as strict and formal as in conventional programming, do not make development of the programs easier. An alternative to using mathematical pseudocode (involving set theory notation or m
Cracked is a defunct American humor magazine. Founded in 1958, Cracked proved to be the most durable of the many publications to be launched in the wake of Mad magazine. In print, Cracked conspicuously copied Mad's layouts and style, featured a simpleminded, wide-cheeked mascot named Sylvester P. Smythe on its covers; the Smythe character was referred to as Cracked's janitor. Unlike Neuman, who appears on covers, Smythe sometimes spoke and was seen inside the magazine, interacting with parody subjects and other regular characters. A 1998 reader contest led to Smythe getting a full middle name: "Phooey." An article on Cracked.com, the website which adopted Cracked's name after the magazine perished, joked that the magazine was "created as a knock-off of Mad magazine just over 50 years ago", it "spent nearly half a century with a fan base comprised of people who got to the store after Mad sold out."Cracked's publication frequency was reduced in the 1990s, was erratic in the 2000s. In 2006, the magazine was revived with a new editorial formula that represented a significant departure from its prior Mad style.
The new format was more akin to "lad" magazines like Maxim and FHM. The new formula, was unsuccessful and Cracked again canceled its print magazine in February 2007 after three issues; that year, the brand was carried over to a website, Cracked.com, now owned by E. W. Scripps; the magazine's first editor was Sol Brodsky, better known as a journeyman artist and production manager and a publishing vice president at Marvel Comics. Cracked's original publisher, Robert C. Sproul's Major Publications imitated other companies' successes in various genres, such as westerns, men's adventure, the Warren Publications mid-1960s revival of horror comics. Editor Terry Bisson recalled, "The whole company was about lowball imitations; the publisher, Robert Sproul, wanted to put out some imitations of western and astrology mags, I was hired to put them together because of my romance mag experience... The pseudomags did pretty well." Many of the Cracked contributors would work on these titles. A number of monster-themed issues were printed under the Cracked umbrella, capitalizing on such publications as Fangoria and Famous Monsters of Filmland.
Sproul published Cracked into the 1980s. However as the company chased publishing trends, its long-running flagship title was Cracked Magazine—or Cracked Mazagine, as its cover read, deliberately misspelling "magazine"; some notable artists have appeared in particular John Severin. Severin was one of the original artists on Mad and worked on EC Comics' war books, as well as being one of the pre-eminent artists in western comics, but he would come to be best known as Cracked's house cartoonist. For 40 years, he was the magazine's mainstay artist illustrating multiple articles in the same issue, all of its covers. Reacting to his own company's obituary of Severin in 2012, Fantagraphics co-publisher Kim Thompson wrote, "I don't think I'm in thinking of Cracked for most of its run as'a bunch of crap, John Severin.'"The magazine regularly featured good girl artist Bill Ward, comic book stalwart Howard Nostrand, gag cartoonists Don Orehek and Charles Rodrigues. In years, the magazine was a useful training ground for such future independent comic book creators as Rick Altergott, Dan Clowes, Peter Bagge.
Clowes would discuss his childhood ambivalence for the magazine with an interviewer: "No one was a fan of Cracked. We would buy Mad every month, but about two weeks we would get anxious for new material. We would tell ourselves,'OK, we are not going to buy Cracked. Never again!' And we'd hold out for a while, but as the month dragged on it just became,'OK, I guess I'll buy Cracked.' You'd bring it home, you'd remember,'Oh yeah, I hate Cracked !'"Other name artists who contributed at least once to Cracked include such Mad veterans as Jack Davis, Will Elder, Al Jaffee, Basil Wolverton, such future Mad contributors as Jack Rickard, Angelo Torres, Bill Wray, Greg Theakston, Dennis Snee, Mike Snider, Dean Norman, Charlie Kadau, May Sakami and Tom Richmond. Others included Marvel Comics regulars Gene Colan. Jack Kirby contributed once in 1960. In its days, Cracked found it difficult to attract and retain the level of talent that the better-paying, better-selling Mad could. Richmond, who drew four articles for Cracked, reported on his webpage that he was paid just $100 for a finished page, a small fraction of what he earned for his first Mad assignment.
Richmond wrote about the bad feeling caused by his short tenure at Cracked: " was upset about my leaving Cracked for Mad, but let’s be real... not doing so would have been the same as a minor league Triple-A shortstop refusing a call up to the majors. That was no decision at all." Mike Snider had been submitting to both publications, made the move to Mad after it accepted an article, okayed by Cracked. One publisher who looked into buying the Cracked operation felt that Mad was "in a class by itself" and that "Cracked couldn't top Mad's lineup". A typical issue of Cracked included two movie parodies illustrated by Severin; the magazine published "interview" articles featuring the recurring character Nanny Dickering. One of the magazine's lon