Instruct: Given a question, retrieve relevant passages that can help answer the question.
Query: Is analog or digital more reliable?
Digital electronics or digital (electronic) circuits are electronics that operate on digital signals. In contrast, analog circuits manipulate analog signals whose performance is more subject to manufacturing tolerance, signal attenuation and noise. Digital techniques are helpful because it is a lot easier to get an electronic device to switch into one of a number of known states than to accurately reproduce a continuous range of values.
The nature of cellular technology renders many phones vulnerable to 'cloning': anytime a cell phone moves out of coverage (for example, in a road tunnel), when the signal is re-established, the phone sends out a 're-connect' signal to the nearest cell-tower, identifying itself and signalling that it is again ready to transmit. With the proper equipment, it's possible to intercept the re-connect signal and encode the data it contains into a 'blank' phone—in all respects, the 'blank' is then an exact duplicate of the real phone and any calls made on the 'clone' will be charged to the original account. This problem was widespread with the first generation analogue technology, however the modern digital standards such as GSM greatly improve security and make cloning hard to achieve.
The stations' digital signals are multiplexed:
KHON-TV discontinued regular programming on its analog signal, over VHF channel 2, on January 15, 2009, the official date in which full-power television stations in the State of Hawaii transitioned from analog to digital broadcasts (six months before the June 12 transition date for full-power stations on the U.S. mainland). The station's digital signal remained on its pre-transition VHF channel 8, using PSIP to display the station's virtual channel as its former VHF analog channel 2.
With respect to the terms "source" and "target" there are two distinct traditions of usage:In ancient Greek the word "αναλογια" ("analogia") originally meant proportionality, in the mathematical sense, and it was indeed sometimes translated to Latin as "proportio". From there analogy was understood as identity of relation between any two ordered pairs, whether of mathematical nature or not. Kant's "Critique of Judgment" held to this notion. Kant argued that there can be exactly the same relation between two completely different objects. The same notion of analogy was used in the US-based SAT tests, that included "analogy questions" in the form "A is to B as C is to "what"?" For example, "Hand is to palm as foot is to ____?" These questions were usually given in the Aristotelian format: HAND : PALM : : FOOT : ____ While most competent English speakers will immediately give the right answer to the analogy question ("sole"), it is more difficult to identify and describe the exact relation that holds both between pairs such as "hand" and "palm", and between "foot" and "sole". This relation is not apparent in some lexical definitions of "palm" and "sole", where the former is defined as "the inner surface of the hand", and the latter as "the underside of the foot". Analogy and abstraction are different cognitive processes, and analogy is often an easier one. This analogy is not comparing "all" the properties between a hand and a foot, but rather comparing the "relationship" between a hand and its palm to a foot and its sole. While a hand and a foot have many dissimilarities, the analogy focuses on their similarity in having an inner surface. A computer algorithm has achieved human-level performance on multiple-choice analogy questions from the SAT test. The algorithm measures the similarity of relations between pairs of words (e.g., the similarity between the pairs HAND:PALM and FOOT:SOLE) by statistical analysis of a large collection of text. It answers SAT questions by selecting the choice with the highest relational similarity.
Early attempts at digital audio workstations in the 1970s and 1980s faced limitations such as the high price of storage, and the vastly slower processing and disk speeds of the time. In 1978, Soundstream (who had made one of the first commercially available digital audio tape recorders in 1977) built what could be considered the first digital audio workstation using some of the most current computer hardware of the time. The "Digital Editing System", as Soundstream called it, consisted of a DEC PDP-11/60 minicomputer running a custom software package called DAP (Digital Audio Processor), a Braegen 14"-platter hard disk drive, a storage oscilloscope to display audio waveforms for editing, and a video display terminal for controlling the system. Interface cards that plugged into the PDP-11's Unibus slots (the "Digital Audio Interface", or "DAI") provided analog and digital audio input and output for interfacing to Soundstream's digital recorders and conventional analog tape recorders. The DAP software could perform edits to the audio recorded on the system's hard disks and provide effects such as crossfades.
Frequency numbers for Lima in analog TV. (most are also available on DTT)National channels from Telefónica's Cable Mágico, the country's most popular operator.Puerto Rico follows USA TV Code system
Before the transistor was invented, radios used vacuum tubes. Although portable vacuum tube radios were produced, they were typically bulky and heavy. The need for a low voltage high current source to power the filaments of the tubes and high voltage for the anode potential typically required two batteries. Vacuum tubes were also inefficient and fragile compared to transistors, and had a limited lifetime.
Around 1976, Philips and Sony showed prototypes of digital audio disc players, which were based on optical videodisc technology. In the interview by Tekla Perry for the IEEE Spectrum, May 2017, Immink explains that he got involved in the CD project at the end of 1979 when Sony and Philips had decided to jointly settle one design. Both Philips and Sony had shown prototype CD players to the press in 1978. The team at Philips, he says, "needed someone to do measurements of the two competing systems, the quality, how they coped with scratches, how they coped with imperfections of the disc. My job with the LaserDisc was finished, so I said, 'Sure, I could do it.'" Both Philips and Sony had come up with different rules for translating digital audio data to sequences of pits and lands. After a lot of experimentation, Immink improved the playing time by thirty percent by inventing a code that could better cope with the servo systems. The encoding system Immink devised came to be called Eight-to-fourteen modulation (EFM).
ITV Digital was a British digital terrestrial television broadcaster which launched a pay-TV service on the world's first digital terrestrial television network. Its main shareholders were Carlton Communications and Granada plc, two franchises of the ITV network. Starting as ONdigital in 1998, the service was re-branded as ITV Digital in July 2001. Low audience figures, piracy issues and an ultimately unaffordable multimillion-pound deal with the Football League led to the broadcaster suffering massive losses, forcing it to enter administration in March 2002. Pay television services ceased permanently on 1 May 2002, and the remaining free-to-air channels such as BBC One and Channel 4 had ceased when the company was liquidated in October, with the terrestrial multiplexes subsequently taken over by Crown Castle and the BBC to create Freeview later that month.
The Compact Cassette originally was intended for use in dictation machines. In this capacity, some later-model cassette-based dictation machines could also run the tape at half speed (⁄ in/s) as playback quality was not critical. The cassette soon became a popular medium for distributing prerecorded music—initially through The Philips Record Company (and subsidiary labels Mercury and Philips in the U.S.). As of 2009, one still finds cassettes used for a variety of purposes, such as journalism, oral history, meeting and interview transcripts, audio-books, and so on. Police are still big buyers of cassette tapes, as some lawyers "don't trust digital technology for interviews". However, they are starting to give way to Compact Discs and more "compact" digital storage media. Prerecorded cassettes were also employed as a way of providing chemotherapy information to recently diagnosed cancer patients as studies found anxiety and fear often gets in the way of the information processing.
Although the daguerreotype process is sometimes said to have died out completely in the early 1860s, documentary evidence indicates that some very slight use of it persisted more or less continuously throughout the following 150 years of its supposed extinction. A few first-generation daguerreotypists refused to entirely abandon their old medium when they started making the new, cheaper, easier to view but comparatively drab ambrotypes and tintypes. Historically minded photographers of subsequent generations, often fascinated by daguerreotypes, sometimes experimented with making their own or even revived the process commercially as a "retro" portraiture option for their clients. These eccentric late uses were extremely unusual and surviving examples reliably dated to between the 1860s and the 1960s are now exceedingly rare.
Since 1980, the popularity of portable radios has declined with the rise of portable audio players and smartphones, which allow users to carry and listen to the music of their choosing and may also include a radio tuner. This began in the late 1970s with boom boxes and portable cassette players such as the Sony Walkman, followed by portable CD players. A common type now is the portable digital audio player. This type of device is a popular choice with listeners who are dissatisfied with terrestrial music radio because of a limited selection of music and reception problems. However, transistor radios are still popular for news, talk radio, weather, live sporting events and emergency alert applications.
Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology would be marketed to consumers. After World War II, an improved form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US and most other developed countries. The availability of multiple types of archival storage media such as Betamax, VHS tape, local disks, DVDs, flash drives, high-definition Blu-ray Discs, and cloud digital video recorders has enabled viewers to watch pre-recorded material—such as movies—at home on their own time schedule. For many reasons, especially the convenience of remote retrieval, the storage of television and video programming now occurs on the cloud. At the end of the first decade of the 2000s, digital television transmissions greatly increased in popularity. Another development was the move from standard-definition television (SDTV) (576i, with 576 interlaced lines of resolution and 480i) to high-definition television (HDTV), which provides a resolution that is substantially higher. HDTV may be transmitted in various formats: 1080p, 1080i and 720p. Since 2010, with the invention of smart television, Internet television has increased the availability of television programs and movies via the Internet through streaming video services such as Netflix, Amazon Video, iPlayer, Hulu, Roku and Chromecast.
Walter stressed the importance of using purely analogue electronics to simulate brain processes at a time when his contemporaries such as Alan Turing and John von Neumann were all turning towards a view of mental processes in terms of digital computation. His work inspired subsequent generations of robotics researchers such as Rodney Brooks, Hans Moravec and Mark Tilden. Modern incarnations of Walter's "turtles" may be found in the form of BEAM robotics.
The first digitally operated and programmable robot was invented by George Devol in 1954 and was ultimately called the Unimate. This ultimately laid the foundations of the modern robotics industry. Devol sold the first Unimate to General Motors in 1960, and it was installed in 1961 in a plant in Trenton, New Jersey to lift hot pieces of metal from a die casting machine and stack them. Devol's patent for the first digitally operated programmable robotic arm represents the foundation of the modern robotics industry.
As the original American digital television transition date of 17 February 2009 approached, XETV had expressed intentions to follow other San Diego-area stations in ceasing transmission of its analog signal. While the U.S. switchover deadline of 17 February was later pushed back to 12 June 2009 and only applied to American-licensed stations in any case, plans were announced to voluntarily make the station's English-language programming digital-only. The analog signal would be repurposed to retransmit the Mexican Galavisión network (not to be confused with the American cable channel of the same name). Claims on XETV's website that the station was indeed going to transmit a digitally-exclusive signal were rescinded on 17 February 2009 as the station decided to delay cutting off its analog signal until after it secured approval from the Mexican government. XETV management later stated that it had decided to maintain its analog signal to benefit Mexican viewers. XETV's analog signal was eventually repurposed on 5 March 2012, when the station began multicasting on its digital signal with the addition of Televisa's youth-oriented Canal 5 network on subchannel 6.2 and on its analog feed, while digital channel 6.1 retained the newscasts, CW network and syndicated programs in English. On the same date, XHBJ-TV channel 45 dropped Canal 5 for Galavisión. Canal 5 replaced XETV's English-language programming on its analog signal, in order to serve Spanish-speaking viewers in Tijuana that did not have television sets with built-in digital tuners or digital converter boxes prior to the Tijuana market's 2013 transition to digital television. The affiliation switch coincided with the commencement of digital multicasting on Televisa's Tijuana stations. Canal 5 moved to its primary channel on 31 May 2017, at which point, the 6.2 subchannel was decommissioned.
The local terrain can also play a major role in limiting broadcast range. Mountain ranges block FM broadcasts, AM broadcasts, and TV broadcasts, and other signals in the VHF and especially UHF ranges, respectively. This terrain shielding occurs when the line of sight is blocked by something through which the radio waves cannot pass, particularly stone. At times this may be moot due to weather, such as when the tall cumulonimbus clouds of a squall line of thunderstorms reflect the signal over the top, like an extremely tall radio tower. Conversely, heavy rain may attenuate the range of even local stations. ATSC digital television is affected by wind and trees (even if not surrounding the transmitter or receiver locations), apparently related to its use of 8VSB modulation instead of COFDM.
So while 4K UHD sounds like it has a pixel structures with 1/4 the area of 1080p, that does not happen with pixel shifting. Only a true 4K projector offers that level of resolution. That's why "true" 4K projectors cost so much more than 4K UHD projectors with otherwise similar feature sets. They produce smaller pixels, finer resolution, no compromising of detail or color from overlapping pixels. By comparison, the slight difference in aspect ratio between DCI and 3840×2160 pixel displays without overlap is insignificant relative to the amount of detail.
This resolution is used mainly in digital cinema production, and has a total of 8,847,360 pixels with an aspect ratio 256135 (≈1910). It was standardized as the resolution of the 4K container format defined by Digital Cinema Initiatives in the Digital Cinema System Specification, and is the native resolution of all DCI-compliant 4K digital projectors and monitors. The DCI specification allows several different resolutions for the content inside the container, depending on the desired aspect ratio. The allowed resolutions are defined in SMPTE 428-1: The DCI 4K standard has twice the horizontal and vertical resolution of DCI 2K (), with four times as many pixels overall.
A recent review by Mikhail Dyakonov in IEEE Spectrum argues that practical quantum computers are not likely to be implemented. He says: "There is a tremendous gap between the rudimentary but very hard experiments that have been carried out with a few qubits and the extremely developed quantum-computing theory, which relies on manipulating thousands to millions of qubits to calculate anything useful. That gap is not likely to be closed anytime soon."
In 2000, XETV began transmitting a digital signal on UHF channel 23, becoming the first San Diego area station to begin digital television transmissions. It was also the first television station in Mexico to operate a digital signal; no other Mexican television station had begun digital operations at that time, and a digital television standard was not formally selected until 2004. It maps on digital tuners in both countries as virtual channel 6.1 through PSIP technology. In January 2006, the Secretariat of Communications and Transportation, which at the time still regulated broadcasting in Mexico, gave formal authorization for XETV's digital signal, with the full callsign XETV-TDT (a suffix standing for "Televisión digital terrestre", or Digital terrestrial television) and an effective radiated power of 402.8 kilowatts.
On May 26, 2012, Adam, C-P and Jeffball of DC949 gave a presentation at the LayerOne hacker conference detailing how they were able to achieve an automated solution with an accuracy rate of 99.1%. Their tactic was to use techniques from machine learning, a subfield of artificial intelligence, to analyse the audio version of reCAPTCHA which is available for the visually impaired. Google released a new version of reCAPTCHA just hours before their talk, making major changes to both the audio and visual versions of their service. In this release, the audio version was increased in length from 8 seconds to 30 seconds, and is much more difficult to understand, both for humans as well as bots. In response to this update and the following one, the members of DC949 released two more versions of Stiltwalker which beat reCAPTCHA with an accuracy of 60.95% and 59.4% respectively. After each successive break, Google updated reCAPTCHA within a few days. According to DC949, they often reverted to features that had been previously hacked.
Those who favour the digital format point to the results of blind tests, which demonstrate the high performance possible with digital recorders. The assertion is that the 'analog sound' is more a product of analog format inaccuracies than anything else. One of the first and largest supporters of digital audio was the classical conductor Herbert von Karajan, who said that digital recording was "definitely superior to any other form of recording we know". He also pioneered the unsuccessful Digital Compact Cassette and conducted the first recording ever to be commercially released on CD: Richard Strauss's "Eine Alpensinfonie".
Personal locator beacons operating on 406 MHz must be registered. PLBs should not be used in cases where normal emergency response (such as 9-1-1) exists.The most important aspect of a beacon in classification is the mode of transmission. There are two valid transmission modes: digital and analog. Where digital usually has a longer range, analog is more reliable. Analog beacons are useful to search parties and SAR aircraft, though they are no longer monitored by satellite.
Since digital circuits are made from analog components, digital circuits calculate more slowly than low-precision analog circuits that use a similar amount of space and power. However, the digital circuit will calculate more repeatably, because of its high noise immunity. On the other hand, in the high-precision domain (for example, where 14 or more bits of precision are needed), analog circuits require much more power and area than digital equivalents.
Analog meters are older designs, but are still preferred by many engineers and troubleshooters. One reason for this is that analog meters are more sensitive to changes in the circuit that is being measured. A digital multimeter samples the quantity being measured over time, and then displays it. Analog multimeters continuously read the test value. If there are slight changes in readings, the needle of an analog multimeter will track them, while digital multimeters may miss them, or be difficult to read. This continuous tracking feature becomes important when testing capacitors or coils, for example. A properly functioning capacitor should allow current to flow when voltage is applied, then the current slowly decreases to zero and this "signature" is easy to see on an analog multimeter but not on a digital multimeter. This is similar when testing a coil, except the current starts low and increases.