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Analog-to-digital converter

In electronics, an analog-to-digital converter is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may provide an isolated measurement such as an electronic device that converts an input analog voltage or current to a digital number representing the magnitude of the voltage or current; the digital output is a two's complement binary number, proportional to the input, but there are other possibilities. There are several ADC architectures. Due to the complexity and the need for matched components, all but the most specialized ADCs are implemented as integrated circuits. A digital-to-analog converter performs the reverse function. An ADC converts a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal; the conversion involves quantization of the input, so it introduces a small amount of error or noise. Furthermore, instead of continuously performing the conversion, an ADC does the conversion periodically, sampling the input, limiting the allowable bandwidth of the input signal.

The performance of an ADC is characterized by its bandwidth and signal-to-noise ratio. The bandwidth of an ADC is characterized by its sampling rate; the SNR of an ADC is influenced by many factors, including the resolution and accuracy, aliasing and jitter. The SNR of an ADC is summarized in terms of its effective number of bits, the number of bits of each measure it returns that are on average not noise. An ideal ADC has an ENOB equal to its resolution. ADCs are required SNR of the signal to be digitized. If an ADC operates at a sampling rate greater than twice the bandwidth of the signal per the Nyquist–Shannon sampling theorem, perfect reconstruction is possible; the presence of quantization error limits the SNR of an ideal ADC. However, if the SNR of the ADC exceeds that of the input signal, its effects may be neglected resulting in an perfect digital representation of the analog input signal; the resolution of the converter indicates the number of discrete values it can produce over the range of analog values.

The resolution determines the magnitude of the quantization error and therefore determines the maximum possible average signal-to-noise ratio for an ideal ADC without the use of oversampling. The values are stored electronically in binary form, so the resolution is expressed as the audio bit depth. In consequence, the number of discrete values available is assumed to be a power of two. For example, an ADC with a resolution of 8 bits can encode an analog input to one in 256 different levels; the values can represent the ranges depending on the application. Resolution can be defined electrically, expressed in volts; the change in voltage required to guarantee a change in the output code level is called the least significant bit voltage. The resolution Q of the ADC is equal to the LSB voltage; the voltage resolution of an ADC is equal to its overall voltage measurement range divided by the number of intervals: Q = E F S R 2 M, where M is the ADC's resolution in bits and EFSR is the full scale voltage range.

EFSR is given by E F S R = V R e f H i − V R e f L o w, where VRefHi and VRefLow are the upper and lower extremes of the voltages that can be coded. The number of voltage intervals is given by N = 2 M, where M is the ADC's resolution in bits; that is, one voltage interval is assigned in between two consecutive code levels. Example: Coding scheme as in figure 1 Full scale measurement range = 0 to 1 volt ADC resolution is 3 bits: 23 = 8 quantization levels ADC voltage resolution, Q = 1 V / 8 = 0.125 V. In many cases, the useful resolution of a converter is limited by the signal-to-noise ratio and other errors in the overall system expressed as an ENOB. Quantization error is introduced by quantization in an ideal ADC, it is a rounding error between the analog input voltage to the output digitized value. The error is signal-dependent. In an ideal ADC, where the quantization error is uniformly distributed between −1/2 LSB and +1/2 LSB, the signal has a uniform distribution covering all quantization levels, the Signal-to-quantization-noise ratio is given by S Q N R = 20 log 10 ⁡ ≈ 6.02 ⋅ Q d B where Q is the number of quantization bits.

For example, for a 16-bit ADC, the quantization error is 96.3 dB below the maximum level. Quantization error is distributed from DC to the Nyquist frequency if part of the ADC's bandwidth is not used, as is the case

Wiegenlied, D 498 (Schubert)

Franz Schubert's Wiegenlied "Schlafe, holder süßer Knabe", D 498, Op. 98, No. 2, is a lullaby composed in November 1816. The song is known as "Mille cherubini in coro" after an Italian language arrangement for voice and orchestra by Alois Melichar; the author of the lyrics is unknown. Alois Melichar arranged Wiegenlied along with incidental music from Schubert's opera Rosamunde to form the song "Mille cherubini in coro" for the 1935 film Vergiß mein nicht, it was performed by the tenor Beniamino Gigli with the Berlin State Opera Orchestra. In more recent times the song was notably sung by tenor Luciano Pavarotti in his Christmas concerts. ScoresInternational Music Score Library Project Indiana University Sheet

Vinton Freedley

Vinton Freedley was an American theater and television producer known for his productions of the works of Cole Porter, George Gershwin, Richard Rodgers and television shows such as Talent Jackpot and Showtime U. S. A.. Freedley was born in Pennsylvania, he graduated Harvard University in 1914 where he was a member of The Delphic Club and The Hasty Pudding. He attended The University of Pennsylvania where he earned a JD degree, he became a member of the historic theatrical club, The Lambs in 1918 Soon after graduating college, Freedley met Alexander A. Aarons with whom he formed a long term producing partnership, their first major hit was Lady Be Good! with music and lyrics by George and Ira Gershwin and featuring Fred Astaire and Adele Astaire. Over the next ten years the pair produced some of the most important works in the Broadway musical canon, featuring some of the most famous songs to emerge from the tin pan alley era, part of what is referred to as "The Great American Songbook." The shows that followed included Tip-Toes, Oh, Kay!, Funny Face, again starring the Astaires.

All the scores were written by the Gershwins. In 1928 Aarons and Freedley produced Here's Howe, featuring the music of Gus Kahn, Joseph Meyer, Irving Caesar. In 1929 followed Spring Is Here and Heads Up!, both with songs by Richard Rodgers and Lorenz Hart. Another Gershwin hit was Girl Crazy; the partnership ended in 1932. Freedley produced 30 shows total on Broadway. Aarons and Freedley built the Alvin Theatre, today known as the Neil Simon Theatre, it is a "musical" house on West 52nd St. in New York with a capacity that fluctuates between 1400 and 1500 depending on the seating configuration. The theatre was designed by architect Herbert J. Krapp; the original name is a portmanteau of the names of the two producers: ALex Aarons and VINton Freedley. Showtime, U. S. A. TV Series 1950, Emcee Talent Jackpot, TV Series 1949, Emcee Stage Door Canteen, 1943 A Dangerous Affair, 1919

Catherine Butler

Catherine Butler is an English academic and author of children's fiction. Butler's most important academic work, Four British fantasists: place and culture in the children's fantasies of Penelope Lively, Alan Garner, Diana Wynne Jones, Susan Cooper won the Mythopoeic Fantasy Award in the Mythopoeic Scholarship category and is in 236 libraries according to WorldCat, has been reviewed in the standard book review sources and academic journals. Another academic work, Teaching Children's Fiction is in 148 libraries. Of Butler's fiction, Timon's Tide is the most held and reviewed: over 300 libraries & reviews. Among her other fiction, Death of a Ghost, The Fetch of Mardy Watt, Calypso Dreaming, The Lurkers, are each in about 100 libraries and with journal reviews. Butler's works include: As Charles Butler: Female Replies to Swetnam the Woman-Hater, ed; the Darkling Timon's Tide Calypso Dreaming The Fetch of Mardy Watt Death of a Ghost The Lurkers Teaching Children's Fiction, ed. Four British Fantasists: Place and Culture in the Children's Fantasies of Penelope Lively, Alan Garner, Diana Wynne Jones, Susan Cooper Kiss of Death Hand of Blood As Catherine Butler: Reading History in Children's Books, with Hallie O'Donovan Roald Dahl: A New Casebook, ed. with Ann Alston Twisted Winter, ed. Philip Pullman: A New Casebook, ed. with Tommy Halsdorf Modern Children's Literature: An Introduction, ed. with Kimberley Reynolds Literary Studies Deconstructed: A Polemic, At some point between 2009 and 2012 Butler began using the name Catherine instead of Charles, evidently as part of transitioning from male to female gender.

Butler is the sister of Martin Butler and the granddaughter of Montagu C. Butler. Catherine Butler's Web Site Charles Butler at the Internet Speculative Fiction Database

Church of St. Michael, Vilnius

St Michael's Church or St. Michael the Archangel Church is a former Roman Catholic church in Vilnius' Old Town, on the right bank of the Vilnia River, it now hosts the Church Heritage Museum. In 1594-97 the church was commissioned by the Chancellor of the Grand Duchy of Lithuania Lew Sapieha as a mausoleum for his family; the construction was finished. 1604, but in 1627 the roofing fell in. During the 1655-61 war with Moscow the Cossacks ravaged the church. A Baroque belfry was built in the 1st quarter of the 18th century; the church was closed down by the tsarist authorities in 1888, in 1905 returned to Sapiehas, renovated in 1905-12. In 1933 both the church and monastery were renovated again. In 1972-2006 the Museum of Architecture operated in the church. Church Heritage Museum was established in 2009 at the church. Museum exhibits the oldest sacral valuables. In the centre of the exposition is treasury of Vilnius Cathedral. Lectures, book presentations are held in the Museum. Educational programmes for children and adults introduce the history of Lithuanian Church, sacral art and architecture.

The harmonious whitewashed façade of St. Michael is built in a transitional style from Renaissance into Baroque; the façade is divided by pilasters with original capitals decorated with floral motifs. Atop the belfry sits an iron weathervane representing Saint Michael the Archangel crushing the devil underfoot; the interior is austere. It is a single-nave space with tunnel vaults; the high altar is of the late Renaissance style, made of black, brown, dark green marble, decorated with white alabaster.

Tropical Storm Ana (2003)

Tropical Storm Ana was the first of two named tropical cyclones, along with Tropical Storm Arlene in 2017, on record in the North Atlantic basin to exist in the month of April. The first tropical cyclone of the 2003 season, it developed as a subtropical cyclone from a non-tropical low on April 20 to the west of Bermuda, it tracked east-southeastward and organized, on April 21 it transitioned into a tropical cyclone with peak winds of 60 mph. Tropical Storm Ana turned east-northeastward weakening due to wind shear and an approaching cold front, on April 24 it became an extratropical cyclone; the storm brushed Bermuda with light rain, the remnants produced precipitation in the Azores and the United Kingdom. Swells generated by the storm capsized a boat along the Florida coastline. A non-tropical low pressure area developed about 240 miles south-southwest of Bermuda on April 18 through the interaction of an upper-level trough and a surface frontal trough; the surface trough, which extended from the gale center to Hispaniola, brought a plume of moisture northward from the Caribbean Sea into the circulation, which caused heavy rainfall in Puerto Rico.

The non-tropical low tracked northward, with a ridge to its east and west, on April 19 the system began producing sporadic convection near its center. After turning to the northwest, it looped southeastward and became separated from the surface frontal system, due to the deepening of the upper-level trough over the system. Convection became better organized over the center, it is estimated the system developed into Subtropical Storm Ana early on April 20 while located about 250 miles west of Bermuda. Operationally, the subtropical cyclone was not classified by the National Hurricane Center until 21 hours later; the subtropical storm tracked east-southeastward and continued to organize, by late on April 20 an upper-level warm core was present over the system. Based on its organization, Ana is estimated to have become a tropical storm by 0000 UTC on April 21. Upon becoming a tropical storm, Ana attained a peak intensity of 60 mph, based on estimates from the Hebert-Poteat technique and data from QuikSCAT.

Shortly thereafter, it made its closest point of approach to Bermuda, when it passed about 130 miles southwest of the island. Operationally, the cyclone was first classified by the National Hurricane Center around this time, when it was considered a subtropical cyclone. Strong upper-level wind shear removed much of the convection, though a small area of thunderstorms persisted near the center; the storm became separated from the upper-level system, the cyclone re-organized, developing an eye feature late on April 21. Embedded within the flow of a cyclone to its north, Ana continued eastward, early on April 22 the wind shear again removed the convection from the center. Convection waxed and waned throughout the day, by April 23 the circulation had deteriorated in organization. After turning to the northeast, the circulation center merged with an approaching cold front on April 24, Tropical Storm Ana completed the transition into an extratropical cyclone; the extratropical storm accelerated east-northeastward before losing its identity within the frontal zone on April 27 southeast of the Azores.

Prior to the development of Ana, the government of Bermuda issued a gale warning for the island. Upon its classification by the National Hurricane Center, a tropical storm warning was issued for Bermuda. Meandering near the island for several days while developing, the storm dropped 2.63 inches of precipitation in a six-day period at the Bermuda International Airport. Winds on the island did not reach tropical storm force. Swells from the storm impacted the coast of Florida; the combination of the swells and an outgoing tide caused a boat to capsize in Jupiter Inlet on April 20. As an extratropical storm, the remnants of Ana dropped 0.87 inches of precipitation in the city of Ponta Delgada in the Azores. Moisture from the remnants of Ana produced beneficial rainfall in the United Kingdom. Two ships recorded tropical storm force winds in association with Ana. On April 20, Ana became the second subtropical cyclone on record in the Atlantic basin in the month of April, after a subtropical storm in 1992.

After attaining tropical characteristics, it became the first tropical storm on record in the month of April, was among the earliest forming tropical or subtropical cyclones in the Atlantic basin. Other storms of the same name List of Bermuda hurricanes List of Azores hurricanes List of off-season Atlantic hurricanes Tropical Storm Ana Tropical Cyclone Report