A digital signal is a signal, being used to represent data as a sequence of discrete values. This contrasts with an analog signal. Simple digital signals represent information in discrete bands of analog levels. All levels within a band of values represent the same information state. In most digital circuits, the signal can have two possible values, they are represented by two voltage bands: one near a reference value, the other a value near the supply voltage. These correspond to the two values "zero" and "one" of the Boolean domain, so at any given time a binary signal represents one binary digit; because of this discretization small changes to the analog signal levels do not leave the discrete envelope, as a result are ignored by signal state sensing circuitry. As a result, digital signals have noise immunity. Digital signals having more than two states are used. For example, signals that can assume three possible states are called three-valued logic. In a digital signal, the physical quantity representing the information may be a variable electric current or voltage, the intensity, phase or polarization of an optical or other electromagnetic field, acoustic pressure, the magnetization of a magnetic storage media, etcetera.
Digital signals are used in all digital electronics, notably computing equipment and data transmission. The term digital signal has related definitions in different contexts. In digital electronics a digital signal is a pulse train, i.e. a sequence of fixed-width square-wave electrical pulses or light pulses, each occupying one of a discrete number of levels of amplitude. A special case is a logic signal or a binary signal, which varies between a low and a high signal level. In digital signal processing, a digital signal is a representation of a physical signal, a sampled and quantized. A digital signal is an abstraction, discrete in time and amplitude; the signal's value only exists at regular time intervals, since only the values of the corresponding physical signal at those sampled moments are significant for further digital processing. The digital signal is a sequence of codes drawn from a finite set of values; the digital signal may be stored, processed or transmitted physically as a pulse-code modulation signal.
In digital communications, a digital signal is a continuous-time physical signal, alternating between a discrete number of waveforms, representing a bitstream. The shape of the waveform depends the transmission scheme, which may be either a line coding scheme allowing baseband transmission; such a carrier-modulated sine wave is considered a digital signal in literature on digital communications and data transmission, but considered as a bitstream converted to an analog signal in electronics and computer networking. In communications, sources of interference are present, noise is a significant problem; the effects of interference are minimized by filtering off interfering signals as much as possible and by using data redundancy. The main advantages of digital signals for communications are considered to be the noise immunity to noise capability, the ability, in many cases such as with audio and video data, to use data compression to decrease the bandwidth, required on the communication media.
A waveform that switches representing the two states of a Boolean value is referred to as a digital signal or logic signal or binary signal when it is interpreted in terms of only two possible digits. The two states are represented by some measurement of an electrical property: Voltage is the most common, but current is used in some logic families. A threshold is designed for each logic family; when below that threshold, the signal is low. The clock signal is a special digital signal, used to synchronize many digital circuits; the image shown can be considered the waveform of a clock signal. Logic changes are triggered either by the falling edge; the rising edge is the transition from a low voltage to a high voltage. The falling edge is the transition from a high voltage to a low one. Although in a simplified and idealized model of a digital circuit, we may wish for these transitions to occur instantaneously, no real world circuit is purely resistive and therefore no circuit can change voltage levels.
This means that during a short, finite transition time the output may not properly reflect the input, will not correspond to either a logically high or low voltage. To create a digital signal, an analog signal must be modulated with a control signal to produce it; the simplest modulation, a type of unipolar encoding, is to switch on and off a DC signal, so that high voltages represent a'1' and low voltages are'0'. In digital radio schemes one or more carrier waves are amplitude, frequency or phase modulated by the control signal to produce a digital signal suitable for transmission. Asymmetric Digital Subscriber Line over telephone wires, does not use binary logic.
European Patent Office
The European Patent Office is one of the two organs of the European Patent Organisation, the other being the Administrative Council. The EPO acts as executive body for the Organisation while the Administrative Council acts as its supervisory body as well as, to a limited extent, its legislative body; the actual legislative power to revise the European Patent Convention lies with the Contracting States themselves when meeting at a Conference of the Contracting States. Within the European Patent Office, examiners are in charge of studying European patent applications, filed by applicants, in order to decide whether to grant a patent for an invention; the patents granted by the European Patent Office are called European patents. The European Patent Office grants European patents for the Contracting States to the European Patent Convention; the EPO provides a single patent grant procedure, but not a single patent from the point of view of enforcement. Hence the patents granted are not European Union patents or Europe-wide patents, but a bundle of national patents.
Besides granting European patents, the EPO is in charge of establishing search reports for national patent applications on behalf of the patent offices of France, Belgium, Italy, Greece, Malta, San Marino, Lithuania and Monaco. The European Patent Office is not a legal entity as such, but an organ of the European Patent Organisation, which has a legal personality; the EPO headquarters are located in Germany. The EPO has a branch in The Hague, sub-offices in Berlin and Vienna, a "liaison bureau" in Brussels, Belgium. At the end of 2009, the European Patent Office had a staff of 6818; the predecessor of the European Patent Office was the Institut International des Brevets or IIB. The premises of the European Patent Office enjoy a form of extraterritoriality. In accordance with the Protocol on Privileges and Immunities, which forms an integral part of the European Patent Convention under Article 164 EPC, the premises of the European Patent Organisation, therefore those of the European Patent Office, are inviolable.
The authorities of the States in which the Organisation has its premises are not authorized to enter those premises, except with the consent of the President of the European Patent Office. Such consent is however "assumed in case of fire or other disaster requiring prompt protective action"; the European Patent Office is directed by a president, responsible for its activities to the Administrative Council. The president represents the European Patent Organisation; the president has therefore a dual role: representative of the European Patent Organisation and head of the European Patent Office. The President of the European Patent Office is appointed by the Administrative Council. A majority of three-quarters of the votes of the Contracting States represented and voting in the Administrative Council is required for the appointment of the President. More the "management of the EPO is dominated by the delegates of the contracting States in the Administrative Council," these delegates being, according to Otto Bossung guided by their national interests rather than by supranational interests such as for instance the implementation of the EU internal market.
The official languages of the European Patent Office are English and German and publications including the European Patent Bulletin and Official Journal of the European Patent Office are published in all three of those languages. Patent applications may be filed in any language provided that a translation into one of the official languages is submitted within two months; the official language that the application is filed in or translated into is taken to be the language of the proceedings and the application is published in that language. Documentary evidence may be submitted in any language, although the EPO may require a translation. Several Contracting States to the European Patent Convention have an official language, not an official language of the EPO, such as Dutch, Italian or Spanish and these languages are referred to as "admissible non-EPO languages". Residents or nationals of such States may submit any documents subject to a time limit in an official language of that State and there is a shorter period of one month for filing a translation into an official language or the document is deemed not to have been filed.
Many EPO fees are reduced by 30% for people who file patent application or other documents in an admissible non-EPO language and subsequently file the necessary translation. The European Patent Office includes the following departments: A Receiving Section, responsible for the examination on filing and the examination as to formal requirements of European patent applications Examining Divisions, responsible for prior art searches and the examination of European patent applications Opposition Divisions, responsible for the examination of oppositions against any European patent A Legal Division Boards of Appeal, responsible for the examination of appeals, An Enlarged Board of Appeal. In practice, the above departments of European Patent Office are organized into three "Directorates-General" and a Boards of Appeal Unit; the three DG, each being directed by a Vice-President, are: DG Patent Granting Process, DG Corporate Services, DG Legal and International Affairs. The European Patent Office does not make decisions on infringement matters.
National courts have jurisdiction over infringement matters regarding European patents. Regarding the validity of European patents however, both the European Patent Office during opposition proceedings (
In computer science, a lookup table is an array that replaces runtime computation with a simpler array indexing operation. The savings in terms of processing time can be significant, since retrieving a value from memory is faster than undergoing an "expensive" computation or input/output operation; the tables may be precalculated and stored in static program storage, calculated as part of a program's initialization phase, or stored in hardware in application-specific platforms. Lookup tables are used extensively to validate input values by matching against a list of valid items in an array and, in some programming languages, may include pointer functions to process the matching input. FPGAs make extensive use of reconfigurable, hardware-implemented, lookup tables to provide programmable hardware functionality. Before the advent of computers, lookup tables of values were used to speed up hand calculations of complex functions, such as in trigonometry and statistical density functions. In ancient India, Aryabhata created one of the first sine tables, which he encoded in a Sanskrit-letter-based number system.
In 493 AD, Victorius of Aquitaine wrote a 98-column multiplication table which gave the product of every number from 2 to 50 times and the rows were "a list of numbers starting with one thousand, descending by hundreds to one hundred descending by tens to ten by ones to one, the fractions down to 1/144" Modern school children are taught to memorize "times tables" to avoid calculations of the most used numbers. Early in the history of computers, input/output operations were slow – in comparison to processor speeds of the time, it made sense to reduce expensive read operations by a form of manual caching by creating either static lookup tables or dynamic prefetched arrays to contain only the most occurring data items. Despite the introduction of systemwide caching that now automates this process, application level lookup tables can still improve performance for data items that if change. Lookup tables were one of the earliest functionalities implemented in computer spreadsheets, with the initial version of VisiCalc including a LOOKUP function among its original 20 functions.
This has been followed by subsequent spreadsheets, such as Microsoft Excel, complemented by specialized VLOOKUP and HLOOKUP functions to simplify lookup in a vertical or horizontal table. This is known as a linear search or brute-force search, each element being checked for equality in turn and the associated value, if any, used as a result of the search; this is the slowest search method unless occurring values occur early in the list. For a one-dimensional array or linked list, the lookup is to determine whether or not there is a match with an'input' data value. An example of a "divide and conquer algorithm", binary search involves each element being found by determining which half of the table a match may be found in and repeating until either success or failure; this is only possible if the list is sorted but gives good performance if the list is lengthy. For a trivial hash function lookup, the unsigned raw data value is used directly as an index to a one-dimensional table to extract a result.
For small ranges, this can be amongst the fastest lookup exceeding binary search speed with zero branches and executing in constant time. One discrete problem, expensive to solve on many computers is that of counting the number of bits which are set to 1 in a number, sometimes called the population function. For example, the decimal number "37" is "00100101" in binary, so it contains three bits that are set to binary "1". A simple example of C code, designed to count the 1 bits in a int, might look like this: This simple algorithm can take hundreds of cycles on a modern architecture, because it makes many branches in the loop - and branching is slow; this can be ameliorated using some other compiler optimizations. There is however a simple and much faster algorithmic solution - using a trivial hash function table lookup. Construct a static table, bits_set, with 256 entries giving the number of one bits set in each possible byte value. Use this table to find the number of ones in each byte of the integer using a trivial hash function lookup on each byte in turn, sum them.
This requires no branches, just four indexed memory accesses faster than the earlier code. The above source can be improved by'recasting"x' as a 4 byte unsigned char array and, coded in-line as a single statement instead of being a function. Note that this simple algorithm can be too slow now, because the original code might run faster from the cache of modern processors, lookup tables do not fit well in caches and can cause a slower access to memory. In data analysis applications, such as image processing, a lookup table is used to transform the input data into a more desirable output format. For example, a grayscale picture of the planet Saturn will be transformed into a color image to emphasize the differences in its rings. A classic example of reducing run-time computations using lookup tables is to obtain the result of a trigonometry calculation, such as the sine of a value. Calculating trigonometric functions can slow a computing application; the same application can finish much sooner when it firs
In control engineering a servomechanism, sometimes shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism. It includes a built-in encoder or other position feedback mechanism to ensure the output is achieving the desired effect; the term applies only to systems where the feedback or error-correction signals help control mechanical position, speed or other parameters. For example, an automotive power window control is not a servomechanism, as there is no automatic feedback that controls position—the operator does this by observation. By contrast a car's cruise control uses closed-loop feedback, which classifies it as a servomechanism. A common type of servo provides position control. Servos are electrical, hydraulic or pneumatic, they operate on the principle of negative feedback, where the control input is compared to the actual position of the mechanical system as measured by some type of transducer at the output. Any difference between the actual and wanted values is amplified and used to drive the system in the direction necessary to reduce or eliminate the error.
This procedure is one used application of control theory. Typical servos can give a linear output. Speed control via a governor is another type of servomechanism; the steam engine uses mechanical governors. Prior to World War II the constant speed propeller was developed to control engine speed for maneuvering aircraft. Fuel controls for gas turbine engines employ either electronic governing. Positioning servomechanisms were first used in military fire-control and marine navigation equipment. Today servomechanisms are used in automatic machine tools, satellite-tracking antennas, remote control airplanes, automatic navigation systems on boats and planes, antiaircraft-gun control systems. Other examples are fly-by-wire systems in aircraft which use servos to actuate the aircraft's control surfaces, radio-controlled models which use RC servos for the same purpose. Many autofocus cameras use a servomechanism to move the lens. A hard disk drive has a magnetic servo system with sub-micrometre positioning accuracy.
In industrial machines, servos are used to perform complex motion, in many applications. A servomotor is a specific type of motor, combined with a rotary encoder or a potentiometer to form a servomechanism; this assembly may in turn form part of another servomechanism. A potentiometer provides a simple analog signal to indicate position, while an encoder provides position and speed feedback, which by the use of a PID controller allow more precise control of position and thus faster achievement of a stable position. Potentiometers are subject to drift when the temperature changes whereas encoders are more stable and accurate. Servomotors are used for both low-end applications. On the high end are precision industrial components that use a rotary encoder. On the low end are inexpensive radio control servos used in radio-controlled models which use a free-running motor and a simple potentiometer position sensor with an embedded controller; the term servomotor refers to a high-end industrial component while the term servo is most used to describe the inexpensive devices that employ a potentiometer.
Stepper motors are not considered to be servomotors, although they too are used to construct larger servomechanisms. Stepper motors have inherent angular positioning, owing to their construction, this is used in an open-loop manner without feedback, they are used for medium-precision applications. RC servos are used to provide actuation for various mechanical systems such as the steering of a car, the control surfaces on a plane, or the rudder of a boat. Due to their affordability and simplicity of control by microprocessors, they are used in small-scale robotics applications. A standard RC receiver sends pulse-width modulation signals to the servo; the electronics inside the servo translate the width of the pulse into a position. When the servo is commanded to rotate, the motor is powered until the potentiometer reaches the value corresponding to the commanded position. James Watt's steam engine governor is considered the first powered feedback system; the windmill fantail is an earlier example of automatic control, but since it does not have an amplifier or gain, it is not considered a servomechanism.
The first feedback position control device was the ship steering engine, used to position the rudder of large ships based on the position of the ship's wheel. John McFarlane Gray was a pioneer, his patented design was used on the SS Great Eastern in 1866. Joseph Farcot may deserve equal credit for the feedback concept, with several patents between 1862 and 1868; the telemotor was invented around 1872 by Andrew Betts Brown, allowing elaborate mechanisms between the control room and the engine to be simplified. Steam steering engines had the characteristics of a modern servomechanism: an input, an output, an error signal, a means for amplifying the error signal used for negative feedback to drive the error towards zero; the Ragonnet power reverse mechanism was a general purpose air or steam-powered servo amplifier for linear motion patented in 1909. Electrical servomechanisms were used as early as 1888 in Elisha Gray's Telautograph. Electrical servomechanisms require a power amplifier. World War II saw the development of electrical fire-control servomechanisms, using an amplidyne as the power amplifier.
Vacuum tube amplifiers were used in the UNISERVO tape drive for the UNIVAC I computer
DVD is a digital optical disc storage format invented and developed in 1995. The medium can store any kind of digital data and is used for software and other computer files as well as video programs watched using DVD players. DVDs offer higher storage capacity than compact discs. Prerecorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD; such discs are a form of DVD-ROM because data can only be not written or erased. Blank recordable DVD discs can be recorded once using a DVD recorder and function as a DVD-ROM. Rewritable DVDs can be erased many times. DVDs are used in DVD-Video consumer digital video format and in DVD-Audio consumer digital audio format as well as for authoring DVD discs written in a special AVCHD format to hold high definition material. DVDs containing other types of information may be referred to as DVD data discs; the Oxford English Dictionary comments that, "In 1995 rival manufacturers of the product named digital video disc agreed that, in order to emphasize the flexibility of the format for multimedia applications, the preferred abbreviation DVD would be understood to denote digital versatile disc."
The OED states that in 1995, "The companies said the official name of the format will be DVD. Toshiba had been using the name ‘digital video disc’, but, switched to ‘digital versatile disc’ after computer companies complained that it left out their applications.""Digital versatile disc" is the explanation provided in a DVD Forum Primer from 2000 and in the DVD Forum's mission statement. There were several formats developed for recording video on optical discs before the DVD. Optical recording technology was invented by David Paul Gregg and James Russell in 1958 and first patented in 1961. A consumer optical disc data format known as LaserDisc was developed in the United States, first came to market in Atlanta, Georgia in 1978, it used much larger discs than the formats. Due to the high cost of players and discs, consumer adoption of LaserDisc was low in both North America and Europe, was not used anywhere outside Japan and the more affluent areas of Southeast Asia, such as Hong-Kong, Singapore and Taiwan.
CD Video released in 1987 used analog video encoding on optical discs matching the established standard 120 mm size of audio CDs. Video CD became one of the first formats for distributing digitally encoded films in this format, in 1993. In the same year, two new optical disc storage formats were being developed. One was the Multimedia Compact Disc, backed by Philips and Sony, the other was the Super Density disc, supported by Toshiba, Time Warner, Matsushita Electric, Mitsubishi Electric, Thomson, JVC. By the time of the press launches for both formats in January 1995, the MMCD nomenclature had been dropped, Philips and Sony were referring to their format as Digital Video Disc. Representatives from the SD camp asked IBM for advice on the file system to use for their disc, sought support for their format for storing computer data. Alan E. Bell, a researcher from IBM's Almaden Research Center, got that request, learned of the MMCD development project. Wary of being caught in a repeat of the costly videotape format war between VHS and Betamax in the 1980s, he convened a group of computer industry experts, including representatives from Apple, Sun Microsystems and many others.
This group was referred to as the Technical Working Group, or TWG. On August 14, 1995, an ad hoc group formed from five computer companies issued a press release stating that they would only accept a single format; the TWG voted to boycott both formats unless the two camps agreed on a converged standard. They recruited president of IBM, to pressure the executives of the warring factions. In one significant compromise, the MMCD and SD groups agreed to adopt proposal SD 9, which specified that both layers of the dual-layered disc be read from the same side—instead of proposal SD 10, which would have created a two-sided disc that users would have to turn over; as a result, the DVD specification provided a storage capacity of 4.7 GB for a single-layered, single-sided disc and 8.5 GB for a dual-layered, single-sided disc. The DVD specification ended up similar to Toshiba and Matsushita's Super Density Disc, except for the dual-layer option and EFMPlus modulation designed by Kees Schouhamer Immink.
Philips and Sony decided that it was in their best interests to end the format war, agreed to unify with companies backing the Super Density Disc to release a single format, with technologies from both. After other compromises between MMCD and SD, the computer companies through TWG won the day, a single format was agreed upon; the TWG collaborated with the Optical Storage Technology Association on the use of their implementation of the ISO-13346 file system for use on the new DVDs. Movie and home entertainment distributors adopted the DVD format to replace the ubiquitous VHS tape as the primary consumer digital video distribution format, they embraced DVD as it produced higher quality video and sound, provided superior data lifespan, could be interactive. Interactivity on LaserDiscs had proven desirable to consumers collectors; when LaserDisc prices dropped from $100 per
In January 2004, Sony announced the Hi-MD media storage format as a further development of the MiniDisc format. With its release in 2004, came the ability to use newly developed, high-capacity 1 gigabyte Hi-MD discs, sporting the same dimensions as regular MiniDiscs; the Hi-MD format can be considered obsolete as the last recorder/player was discontinued in 2011. The discs themselves were withdrawn from sale in September 2012, though regular MiniDiscs are still available; the ability to save non-audio data such as documents and pictures Longer playback and recording times per disc The ability to record in linear PCM, offering CD-quality audio. This eliminates compression artifacts that occur when recording directly to lossy audio formats such as Sony's ATRAC, or other formats like MP3, AAC, Windows Media Audio; the introduction of a new ATRAC3plus codec with new Hi-LP and Hi-SP bitrates Compatibility with standard MiniDiscsHi-MD offers the choice of several codecs for audio recording: PCM, Hi-SP and Hi-LP, each selectable on the Hi-MD Walkman itself.
PCM is the highest quality mode, followed by Hi-SP Hi-LP. PCM mode allows 94 minutes of lossless CD-quality audio to be recorded to a 1 GB Hi-MD disc. Hi-SP allows seven hours and fifty-five minutes of audio to be recorded on a 1 GB Hi-MD. Hi-LP allows 34 hours on a 1 GB Hi-MD; each of these codecs is available natively for recording on standalone Hi-MD devices. Additional bitrates are available with SonicStage software on the computer. Up to 45 hours of audio can be recorded per disc at the lowest-quality setting via SonicStage PC transfer. All Hi-MD units have the ability to play back regular MiniDiscs. Most Hi-MD Walkmans have the capability to record standard MiniDiscs in standard SP, LP2 and LP4 codecs in MD mode, ideal for creating discs intended to be played back in older MiniDisc units. Hi-MD discs offer the ability to store computer files in addition to audio data. For example, a Hi-MD disc could have both school or work documents, videos, etc. as well as music if desired. When connected to a computer, a Hi-MD Walkman is seen as standard USB Mass Storage device, just like a USB stick or external hard drive.
On a Windows computer, a Hi-MD device is listed as "Removable Disk" in "My Computer". The disc has a FAT filesystem. Hi-MD units are powered by the USB bus when connected—just like USB flash drives, they do not require additional power when plugged into a computer. Sony's SonicStage music management software is not needed to manipulate files on the discs. However, when SonicStage software is active, the recorder is not treated as a data storage device—SonicStage "takes over" the management of the device; this is necessary. Among these are some for reading/writing DRM-data, setting/getting the date on the device, erasing/formatting of the disc, control of audio-playback and reading defect-lists; when connected to a PC, "PC--MD" appears on the Hi-MD device's display to indicate the unit is connected in PC—MD mode. In PC—MD mode, pressing Play on the unit, for example, results in "PC--MD" flashing, indicating this function cannot be activated from the device when connected to the computer, it is a slave to the computer in this mode.
PC—MD status is constant as long as the unit is connected via USB cable. To play back Hi-MD audio data on the PC, SonicStage is needed, it can be done in two ways: Launch SonicStage. Play audio from Hi-MD inside SonicStage; the audio is played back on the computer's PC speakers. SonicStage reads the audio data straight from the Hi-MD disc. Transfer the audio data to the PC in SonicStage. Play the audio back from the PC's hard drive. Once the operation of transferring audio with SonicStage is completed, the audio itself can be saved in any number of ways. Saving audio in SonicStage in standard WAV format is a accepted way to get the audio into many third-party applications like editors and sound analyzers; the user can proceed to record CDs, edit the audio, archive to format of choice, etc. Hi-MD units can play back standard MiniDiscs recorded in non-Hi-MD units, in addition to record on standard MiniDiscs and higher-capacity 1 GB Hi-MD discs. There are two user-selectable operational modes on Hi-MD units: Hi-MD mode.
These are automatically selected. However, when a blank disc is inserted, the recorder will default to the user-selectable Disc Mode for any recordings made on it; the default Disc Mode on Hi-MD devices is Hi-MD mode. MD mode is useful when intending to record on a standard MiniDisc using standard MD codecs for playback on devices that are not Hi-MD compatible. Data storage cannot be used in MD mode. Hi-MD mode is useful when the benefits of Hi-MD mode are to be used, such as increased capacity on standard MiniDiscs, new codec choices and the ability to save da
Kees Schouhamer Immink
Kornelis Antonie "Kees" Schouhamer Immink is a Dutch scientist and entrepreneur, who pioneered and advanced the era of digital audio and data recording, including popular digital media such as Compact Disc, DVD and Blu-ray Disc. He has been a prolific and influential engineer, who holds more than 1100 U. S. and international patents. A large portion of the used audio and video playback and recording devices use technologies based on his work, his contributions to coding systems assisted the digital video and audio revolution, by enabling reliable data storage at information densities unattainable. Immink received several tributes that summarize the impact of his contributions to the digital audio and video revolution. Among the accolades received are the IEEE Medal of Honor "for pioneering contributions to video and data recording technology, including compact disc, DVD, Blu-ray", the Edison Medal and an individual Technology Emmy award by the National Academy of Television Arts and Sciences.
Beatrix, Queen of the Netherlands bestowed him a knighthood in 2000. Immink holds the position of president of Turing Machines Inc, founded in 1998. During his career, Immink, in addition to his practical contributions, has contributed to information theory, he wrote including Codes for Mass Data Storage Media. He has been an adjunct professor at the Institute for Experimental Mathematics, University of Duisburg and Essen, since 1994, as well as affiliated with the National University of Singapore as a visiting professor since 1997. Immink obtained an Engineer's degree in electrical engineering and a PhD degree from Eindhoven University of Technology on a thesis entitled Properties and Constructions of Binary Channel Codes. Fresh from engineering school, in 1967, he joined Philips Research Labs in Eindhoven, where he spent thirty years in a fruitful association; the renowned physicist Hendrik Casimir was director of Philips Research till 1972. Immink described the atmosphere at that time: "We were able to conduct whatever research we found relevant, had no pre-determined tasks.
We went not knowing that we would do that day. This view – or rather ambiguous view – on how research should be conducted, led to amazing inventions as a result, it was an innovation heaven". Immink worked in various groups, in 1974, he joined the research group Optics, where pioneering work was done on optical laserdisc systems, he contributed to the electronics and servo technology of the video disc. In a joint effort, MCA and Philips brought the laserdisc system to the market. Laserdisc was first available in Atlanta in 1978, two years after the VHS and four years before the CD; the Laserdisc never managed a significant presence in market share. The Philips/MCA Laserdisc operation was not successful and discontinued in 1981. 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 on 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. Immink took part in the joint Sony–Philips task force, which developed the Compact Disc standard, the Red Book, he contributed to the CIRC coding schemes. In the article, "Shannon and the Compact Disc", Immink presents a historical review of the years leading up to the launch of the CD, the various crucial decisions made.
He refutes the urban legend that the compact disc's diameter was increased from 115 to 120 mm to hold the 74 minutes playing time of Beethoven's Ninth Symphony conducted by Wilhelm Furtwängler. Commercial disputes played a part. After the CD standard was set in 1980, Immink and his co-workers conducted pioneering experiments with magneto-optical audio recording on pre-grooved discs, they found a simple method to extend the analog videodisc standard with digital sound. The new systems were brought to market as CD Video. Laserdiscs fabricated after 1984 have digitally encoded sound signals. In 1993, Toshiba engineers developed the successor of the Compact Disc. Immink was a member of the Philips and Sony task force, which developed a competing disc format, called MultiMedia CD. Immink created EFMPlus, a more efficient successor of EFM used in CD; the electronics industry feared a repeat of the format war between Betamax in the 1980s. IBM's president, Lou Gerstner, urged them to adopt Immink’s EFMPlus coding scheme as EFM has a proven record.
In September 1995, an agreement was made among the major industries: Philips/Sony surrendered to Toshiba's SuperDensity Disc and Toshiba accepted the EFMPlus modulation. The DVD encompasses the sound-only Super Audio CD and DVD-audio formats, developed independently by Sony and Toshiba, which are incompatible formats for delivering high-fidelity audio content. SACD i