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Digital-to-analog converter

In electronics, a digital-to-analog converter is a system that converts a digital signal into an analog signal. An analog-to-digital converter performs the reverse function. There are several DAC architectures. Digital-to-analog conversion can degrade a signal, so a DAC should be specified that has insignificant errors in terms of the application. DACs are used in music players to convert digital data streams into analog audio signals, they are used in televisions and mobile phones to convert digital video data into analog video signals which connect to the screen drivers to display monochrome or color images. These two applications use DACs at opposite ends of the frequency/resolution trade-off; the audio DAC 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 matched components, all but the most specialized DACs are implemented as integrated circuits. Discrete DACs would be high-speed low-resolution power-hungry types, as used in military radar systems.

High-speed test equipment sampling oscilloscopes, may use discrete DACs. A DAC converts an abstract finite-precision number into a physical quantity. In particular, DACs are used to convert finite-precision time series data to a continually varying physical signal. An ideal DAC converts the abstract numbers into a conceptual sequence of impulses that are processed by a reconstruction filter using some form of interpolation to fill in data between the impulses. A conventional practical DAC converts the numbers into a piecewise constant function made up of a sequence of rectangular functions, modeled with the zero-order hold. Other DAC methods produce a pulse-density modulated output that can be filtered to produce a smoothly varying signal; as per the Nyquist–Shannon sampling theorem, a DAC can reconstruct the original signal from the sampled data provided that its bandwidth meets certain requirements. Digital sampling introduces quantization error that manifests as low-level noise in the reconstructed signal.

DACs and ADCs are part of an enabling technology that has contributed to 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 the analog signal is converted to a digital stream by an ADC. The digital stream is divided into network packets where it may be sent along with other digital data, not audio; the packets are received at the destination, but each packet may take a different route and may not arrive at the destination in the correct time order. The digital voice data is 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 loudspeaker, which produces sound. Most modern audio signals are stored in digital form 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, PC sound cards.

Specialist standalone DACs can be found in high-end hi-fi systems. These take the digital output of a compatible CD player or dedicated transport and convert the signal into an analog line-level output that can be fed into an amplifier to drive speakers. Similar digital-to-analog converters can be found in digital speakers such as USB speakers, in sound cards. In voice over IP applications, the source must first be digitized for transmission, so it undergoes conversion via an ADC and is reconstructed into analog using a DAC on the receiving party's end. Video sampling tends to work on a different scale altogether thanks to the nonlinear response both of cathode ray tubes and the human eye, using a "gamma curve" to provide an appearance of evenly distributed brightness steps across 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.

Given this inherent distortion, it is not unusual for a television or video projector to truthfully claim a linear contrast ratio of 1000:1 or greater, equivalent to 10 bits of audio precision 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 used than digital, but this changed as flat panel displays with DVI and/or HDMI connections became more widespread. A video DAC is, incorporated in any digital video player with analog outputs; the DAC is integrated with some memory, which contains conversion tables for gamma correction and brightn


Monasteraden is a village in County Sligo, Ireland. The village is located on the shores of Lough Gara. St Aiden's church is the village's church. Other sights include Lough Gara Lodge, Slí na Croí's Roundhouse Ecolodge, Drury's pub and the general store. Monasteraden lies to the west of Lough Gara and with the Curlew Mountains inlier of sandstones and conglomerates to the North. To the west lies the townland of Clogher with Edmondstown and Ballaghaderreen in the neighbouring County Roscommon. Monasteraden is situated in the barony of Coolavin in the south of the County of Sligo. There is a holy well called St Attractas and, where many people used to get their drinking water; the lake is divided by the bridge at Clooncunny. Island Road railway station served Monasteraden and used to have many trains passing by on the Ballaghaderreen branch line with connections to Dublin but, closed in 1963 and they station building is now a comfortable home for a local family; the nearest railway station is now Boyle, some 10 miles away.

One Bus Éireann service a week stops at Monasteraden on its way to Dublin. The nearest bus station is in Ballaghaderreen, about 4 miles miles away and has several buses travelling to and from Dublin daily. There is a national school, St. Aiden's in Monasteraden, they have been noted for their work with film, including producing a 32 minute movie entitled "The Train" bringing together rare footage and interviews with local people associated with the Ballaghaderreen branch line which had a station serving they village. List of towns and villages in Ireland

Alastair Humphreys

Alastair Humphreys is an English adventurer and motivational speaker. Over a four-year period he bicycled 46,000 miles around the world, he was a National Geographic Adventurer of the Year in 2012. He is responsible for the rise of the idea of the microadventure – short, accessible adventures. Humphreys was educated at Shrewsbury School studied Zoology at Edinburgh and Oxford, he began his first expedition in August 2001 from his Yorkshire home. Passing south through Europe and Africa, he crossed to South America by sea from Cape Town and proceeded up the west coast of the Americas, crossed from Alaska to Magadan in Russia, Japan westward across China and Central Asia to return to Europe, his journey included raising funds and awareness for a charity called Homes for Children. Humphreys arrived home in November 2005, having ridden over 46,000 miles in four years and three months, he has written several books about his experiences, titled Moods of Future Joys, Ten Lessons from the Road and Sunshine and a series of three children's books called The Boy Who Biked the World.

Humphreys wrote a book about walking across India called There Are Other Rivers. Humphreys works as a motivational speaker and occasional adventure author; the President of the Royal Geographical Society said, "With the possible exception of Sir David Attenborough, the best lecture, the longest applause that I have heard in the past 15 years."In 2008, Humphreys competed in the Marathon des Sables, a 150 miles run across the Sahara desert. He broke his foot during the race but still completing the event, he narrowly missed being in the top-100 finishers. In February 2009, Humphreys rowed across the English Channel with Major Phil Packer to raise £1 million for Help for Heroes. In spring 2009, Humphreys walked across India, in 2010 he walked and packrafted across Iceland, his 2011 "Year of Microadventure" earned him the National Geographic accolade of "Adventurer of the Year". Humphreys pioneered the concept and coined the term "microadventure" which has since gained him a global following. "#microadventure" is now used as a popular hashtag on social media sites.

In 2012 he joined Marin Medak, Simon Osborne and Steve Bowens to row unsupported across the Atlantic Ocean. The team finished their journey in Barbados after 45 days and 15 hours at sea, he walked across the Empty Quarter desert with Leon McCarron and undertook an expedition in Greenland. In 2013, Humphreys released his first documentary film, Into the Empty Quarter, documenting his walk through the Empty Quarter desert with Leon McCarron The film premiered at the Royal Geographical Society, London, in November 2013. Alastair Humphreys, 2007. Moods of Future Joys: Around the World by Bike – Part 1. Eye Books. ISBN 978-1-903070-56-7. Alastair Humphreys, 2008. Thunder and Sunshine: Around the World by Bike – Part 2. Eye Books. ISBN 978-1-903070-54-3 Alastair Humphreys, 2009. Ten Lessons From The Road. Eye Books. Alastair Humphreys, 2011; the Boy Who Biked the World. Eye Books. Alastair Humphreys, 2011. There Are Other Rivers. Self Published. Alastair Humphreys, 2014. Microadventures. Harper Collins. Alastair Humphreys, 2016.

Grand Adventures. Harper Collins. Bicycle touring Alastair Humphreys' Homepage

Blair Hopping

Blair Robert Hopping is a field hockey player from New Zealand, who earned his first cap for the national team, nicknamed The Black Sticks, in 2000 against Pakistan. He competed for New Zealand at the 2004 Summer Olympics in Athens, the 2008 Summer Olympics in Beijing and the 2012 Summer Olympics in London and at the 2002 Commonwealth Games in Manchester and the 2006 Commonwealth Games in Melbourne. Hopping taught Physical Education at Rangitoto College on Auckland's North Shore and coaches the school's 1st XI, he left that to join TigerTurf, New Zealand's only Synthetic Sports Surface manufacturer, on a part-time basis in 2006 and full-time since 2011. After retiring from Hockey, Blair now helps to build new Hockey surfaces in New Zealand. 2001 – World Cup Qualifier 2002 – World Cup 2002 – Commonwealth Games 2003 – Sultan Azlan Shah Cup 2003 – Champions Challenge 2004 – Olympic Qualifying Tournament 2004 – Olympic Games 2004 – Champions Trophy 2005 – Sultan Azlan Shah Cup 2006 – Commonwealth Games 2006Hockey World Cup 2007 – Champions Challenge 2008 – Olympic Games 2012 – Olympic Games

Oleg Markov

Oleg Markov is a professional Australian rules footballer playing for the Richmond Football Club in the Australian Football League. He was drafted to Richmond in the third round of the 2015 national draft and made his debut in round 16 of the 2016 season. In 2019 he won a VFL premiership while playing with the club's reserves side. Markov was born in Vitebsk in the eastern European nation of Belarus, he moved with his family to Adelaide at the age of ten months. Markov has a mixed athletic background including in high jump, he was talented at the sport, placing fifth one year at the Australian All Schools championships. He began playing football for the first time at age ten, picking up the sport in the playground of his Adelaide school. Markov played his first junior football for Gepps Cross before moving to the North Adelaide Under 13s side. In 2014 Markov played Under 18's football with the North Adelaide Football Club, his season was limited however by two significant collar-bone injuries. Markov went undrafted in 2014 and instead returned to North Adelaide for the 2015 season.

He appeared in matches in the club's reserves and senior side. He played for the South Australian side at 2015's National Under-18 championships, appearing in five matches. In the second round of the tournament he kicked five goals and recorded 16 disposals in an impressive performance against Vic Metro. Markov was drafted by Richmond with the club's second selection and 50th selection overall in the 2015 draft. Markov made his AFL debut in round 16 of the 2016 season in a match against the Western Bulldogs at Etihad Stadium, he recorded nine marks for the match. The following week he kicked his first career goal, in a round 17 victory against Essendon. Markov finished the season having played eight consecutive matches to close out the season and holding averages of 15.4 disposals and 6.3 marks per game. He ranked ninth at the club for metres gained per match. After spending the first four weeks of the 2017 season in the reserves, Markov was called up to playing his first AFL match of the season in round 5 against Melbourne.

In round 6 he kicked an equal team high two goals in the club's loss to Adelaide. He remained in the club's senior side for the following two weeks, but was dropped after a six disposal game in the round 8 loss to Fremantle. Markov returned to senior football for a single match in round 15, being omitted form the side the following week, he had another two match streak in rounds 22 and 23, but was dropped from the club's qualifying final team to play the following week. Markov's year did not end there however; the streak included playing in the losing grand final against Port Melbourne. At season's end he had played seven senior matches. In the weeks following the end of the 2017 season, Markov underwent shoulder surgery. Though he would return to conditioning work the ongoing injury rehabilitation would limit his skills and contact training into the start of the 2018 calendar year; as a result Markov was not in selection consideration in the first month of the AFL season, instead playing reserves football in the VFL.

There he missed two weeks of football as a result. After returning from that injury Makov played a further four matches at VFL level including in a new role as a hybrid defensive player, taking a one-on-one role against opponents' third-tall forward in addition to his normal half-back rebounding role. In early-May though Markov sustained a match-ending knee injury during the first minute of a VFL match against Williamstown. Scans would reveal the injury to be a strained medial collateral ligament that would see him miss an expected four to six-weeks. Markov made a return to training behind schedule in early-July and played VFL football again in the penultimate weekend of the month, he sustained yet another knee injury in that match however, this time suffering a torn meniscus that required surgery to repair. Markov made a return to running and conditioning in mid-August and to competitive football in Richmond's losing VFL qualifying final against Williamstown in September, he recorded 15 disposals in the match and repeated the effort with a further 15 in the club's knock-out semi-final loss to the Essendon reserves side the following week.

Markov finished the season having played 10 matches with the club's reserves side in the VFL but failed to play a match at AFL level. After rebuilding some of his muscle mass lost during injury rehabilitation in the year prior, Markov spent the 2018/19 off-season developing his defensive skills in order to complement his rebounding abilities. In February he missed some training due to a minor knee complaint but recovered in time to feature in each of the club's two official pre-season matches in March. Despite showing improvements on his output from his last AFL match two years prior, he was unable to gain selection in round 1's season opener against Carlton. An injury to fellow half-back Bachar Houli saw Markov called up to AFL the next week however, contributing eight and 20 disposals over a two match stint at AFL level, he would be dropped back to VFL level after those two matches, where he managed to play just one match before suffering a torn meniscus in his right knee. While an initial diagnosis suggested a recovery time of six to eight weeks, a successful surgical operation allowed to Markov to return to VFL football within four.

He missed one further VFL match in early June due to illness before being suspended for another that month. In early July, AFL released GPS data identified Markov as the fastest player in the league that season, having achieved a top sprint speed of 37.4 kilometr

Ituxi Extractive Reserve

The Ituxi Extractive Reserve is an extractive reserve in the state of Amazonas, Brazil. The Ituxi Extractive Reserve is in the municipality of Amazonas, it has an area of 776,940 hectares. The reserve in on the banks of Ituxi River, a blackwater river, its tributaries, the Punicici and Curequetê; the Ituxi River, a tributary of the Purus River, flows through the reserve in an northeast direction. The reserve is bounded by the Mapinguari National Park to the south and east and the Iquiri National Forest to the west and north. Vegetation includes terra firma forest, seasonally flooded várzea forest and capoeira, with great biological diversity. Plant species include Parkia Pendula, Brazil nut and Copaíba; the reserve has many endemic fish species. There are about 500 people in 20 extractive communities; these communities include Mangutiari, Pedreiras do Amazonas, Praia Alta, Cabeçudo, Estirão da Pedreira, Vila Canaã, Vila Vitória, Curequetê, Carajuriã, São Luis, Punicici, Vera, Nova Esperança and Pacu.

The families extract fruit and other seasonal products such as Brazil nuts, natural rubber, copaiba, açaí palm fruit and vines. Fishing in the lakes and flooded forests provides an important source of food and income for the residents; the Ituxi Extractive Reserve was created by federal decree on 5 June 2008 with an area of about 776,940 hectares. IT is administered by the Chico Mendes Institute for Biodiversity Conservation, it is classed as IUCN protected area category VI. The purpose is to protect the livelihoods and ensure use and conservation of natural resources traditionally used by the communities in the reserve. On 18 September 2008 INCRA recognised the reserve as supporting 300 families of small farmers, who would be eligible for PRONAF support; the deliberative council of the reserve was created on 4 November 2010. An ordinance of 9 January 2012 established a joint planning process for conservation units in the BR-319 area of influence, which are the Abufari Biological Reserve, Cuniã Ecological Station, Nascentes do Lago Jari National Park, Mapinguari National Park, Balata-Tufari National Forest, Humaitá National Forest, Iquiri National Forest, Lago do Capanã-Grande Extractive Reserve, Ituxi Extractive Reserve, Médio Purus Extractive Reserve and Lago do Cuniã Extractive Reserve.

In July 2012 ICMBio arranged a three-day workshop in the Floresta community in the reserve, supported by a representative of the Tropical Forest Institute and others. Objectives included giving the residents an update on progress in preparing the community forest management plan, informing the residents about the business plan for commercializing wood; the institutes had entered a partnership with the Association of Agroextractive Producers of the Assembly of God of Ituxi River to prepare a training plan for forest management. The Sustainable Forestry Management Plan was approved in June 2014, covering an area of 1,400 hectares divided into ten units of annual production. Sustainable logging is allowed in the reserve as an alternative source of income. All wood must be certified under the DOF system operated by the Brazilian Institute of Environment and Renewable Natural Resources; as of 2016 the Ituxi Extractive Reserve was supported by the Amazon Region Protected Areas Program