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78-599: The Kaiser window and its Fourier transform are given by : where : For digital signal processing , the function can be sampled symmetrically as : where the length of the window is N + 1 , {\displaystyle N+1,} and N can be even or odd. (see A list of window functions ) In the Fourier transform, the first null after the main lobe occurs at f = 1 + α 2 L , {\displaystyle f={\tfrac {\sqrt {1+\alpha ^{2}}}{L}},} which

156-501: A field-effect transistor , or may have two kinds of charge carriers in bipolar junction transistor devices. Compared with the vacuum tube , transistors are generally smaller and require less power to operate. Certain vacuum tubes have advantages over transistors at very high operating frequencies or high operating voltages, such as Traveling-wave tubes and Gyrotrons . Many types of transistors are made to standardized specifications by multiple manufacturers. The thermionic triode ,

234-532: A p-n-p transistor symbol, the arrow " P oints i N P roudly". However, this does not apply to MOSFET-based transistor symbols as the arrow is typically reversed (i.e. the arrow for the n-p-n points inside). The field-effect transistor , sometimes called a unipolar transistor , uses either electrons (in n-channel FET ) or holes (in p-channel FET ) for conduction. The four terminals of the FET are named source , gate , drain , and body ( substrate ). On most FETs,

312-655: A pulse train , which is typically generated by the switching of a transistor . Digital signal processing and analog signal processing are subfields of signal processing. DSP applications include audio and speech processing , sonar , radar and other sensor array processing, spectral density estimation , statistical signal processing , digital image processing , data compression , video coding , audio coding , image compression , signal processing for telecommunications , control systems , biomedical engineering , and seismology , among others. DSP can involve linear or nonlinear operations. Nonlinear signal processing

390-479: A real-time computing requirement and the signal data (either input or output) exists in data files, processing may be done economically with a general-purpose computer. This is essentially no different from any other data processing , except DSP mathematical techniques (such as the DCT and FFT ) are used, and the sampled data is usually assumed to be uniformly sampled in time or space. An example of such an application

468-476: A vacuum tube invented in 1907, enabled amplified radio technology and long-distance telephony . The triode, however, was a fragile device that consumed a substantial amount of power. In 1909, physicist William Eccles discovered the crystal diode oscillator . Physicist Julius Edgar Lilienfeld filed a patent for a field-effect transistor (FET) in Canada in 1925, intended as a solid-state replacement for

546-578: A device had been built. In 1934, inventor Oskar Heil patented a similar device in Europe. From November 17 to December 23, 1947, John Bardeen and Walter Brattain at AT&T 's Bell Labs in Murray Hill, New Jersey , performed experiments and observed that when two gold point contacts were applied to a crystal of germanium , a signal was produced with the output power greater than the input. Solid State Physics Group leader William Shockley saw

624-600: A few hundred milliwatts, but power and audio fidelity gradually increased as better transistors became available and amplifier architecture evolved. Modern transistor audio amplifiers of up to a few hundred watts are common and relatively inexpensive. Before transistors were developed, vacuum (electron) tubes (or in the UK "thermionic valves" or just "valves") were the main active components in electronic equipment. The key advantages that have allowed transistors to replace vacuum tubes in most applications are Transistors may have

702-425: A field-effect transistor (FET) by trying to modulate the conductivity of a semiconductor, but was unsuccessful, mainly due to problems with the surface states , the dangling bond , and the germanium and copper compound materials. Trying to understand the mysterious reasons behind this failure led them instead to invent the bipolar point-contact and junction transistors . In 1948, the point-contact transistor

780-412: A particular type, varies depending on the collector current. In the example of a light-switch circuit, as shown, the resistor is chosen to provide enough base current to ensure the transistor is saturated. The base resistor value is calculated from the supply voltage, transistor C-E junction voltage drop, collector current, and amplification factor beta. The common-emitter amplifier is designed so that

858-467: A silicon MOS transistor in 1959 and successfully demonstrated a working MOS device with their Bell Labs team in 1960. Their team included E. E. LaBate and E. I. Povilonis who fabricated the device; M. O. Thurston, L. A. D’Asaro, and J. R. Ligenza who developed the diffusion processes, and H. K. Gummel and R. Lindner who characterized the device. With its high scalability , much lower power consumption, and higher density than bipolar junction transistors,

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936-605: A small change in voltage ( V in ) changes the small current through the base of the transistor whose current amplification combined with the properties of the circuit means that small swings in V in produce large changes in V out . Various configurations of single transistor amplifiers are possible, with some providing current gain, some voltage gain, and some both. From mobile phones to televisions , vast numbers of products include amplifiers for sound reproduction , radio transmission , and signal processing . The first discrete-transistor audio amplifiers barely supplied

1014-562: A tool for analyzing stability issues of digital IIR filters. It is analogous to the Laplace transform , which is used to design and analyze analog IIR filters. A signal is represented as linear combination of its previous samples. Coefficients of the combination are called autoregression coefficients. This method has higher frequency resolution and can process shorter signals compared to the Fourier transform. Prony's method can be used to estimate phases, amplitudes, initial phases and decays of

1092-440: A type of 3D non-planar multi-gate MOSFET, originated from the research of Digh Hisamoto and his team at Hitachi Central Research Laboratory in 1989. Because transistors are the key active components in practically all modern electronics , many people consider them one of the 20th century's greatest inventions. The invention of the first transistor at Bell Labs was named an IEEE Milestone in 2009. Other Milestones include

1170-416: A weaker input signal, acting as an amplifier . It can also be used as an electrically controlled switch , where the amount of current is determined by other circuit elements. There are two types of transistors, with slight differences in how they are used: The top image in this section represents a typical bipolar transistor in a circuit. A charge flows between emitter and collector terminals depending on

1248-758: A window of length 2 N , where by construction d n satisfies the Princen-Bradley condition for the MDCT (using the fact that w N − n = w n ): d n + ( d n + N ) = 1 (interpreting n and n  +  N modulo 2 N ). The KBD window is also symmetric in the proper manner for the MDCT: d n  =  d 2 N −1− n . The KBD window is used in the Advanced Audio Coding digital audio format. Digital signal processing Digital signal processing ( DSP )

1326-461: A working bipolar NPN junction amplifying germanium transistor. Bell announced the discovery of this new "sandwich" transistor in a press release on July 4, 1951. The first high-frequency transistor was the surface-barrier germanium transistor developed by Philco in 1953, capable of operating at frequencies up to 60 MHz . They were made by etching depressions into an n-type germanium base from both sides with jets of indium(III) sulfate until it

1404-420: Is a semiconductor device used to amplify or switch electrical signals and power . It is one of the basic building blocks of modern electronics . It is composed of semiconductor material , usually with at least three terminals for connection to an electronic circuit . A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because

1482-440: Is a versatile field supported by a wide array of software tools. From high-level environments like MATLAB and Python to low-level programming with C/C++, these tools cater to various needs, whether for research, education, or industry applications. As DSP continues to evolve, these software tools play a critical role in advancing the capabilities and efficiencies of signal processing technologies. Transistor A transistor

1560-452: Is an open-source software development toolkit that provides signal processing blocks to implement software-defined radios (SDRs) and signal processing systems. GNU Radio is used in academic research, prototyping of communication systems, and hobbyist projects involving radio and wireless communications. GNU Octave is an open-source alternative to MATLAB, providing a similar environment for numerical computations and signal processing. Octave

1638-612: Is analysis of signal properties. The engineer can study the spectrum to determine which frequencies are present in the input signal and which are missing. Frequency domain analysis is also called spectrum- or spectral analysis . Filtering, particularly in non-realtime work can also be achieved in the frequency domain, applying the filter and then converting back to the time domain. This can be an efficient implementation and can give essentially any filter response including excellent approximations to brickwall filters . There are some commonly used frequency domain transformations. For example,

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1716-516: Is any wavelet transform for which the wavelets are discretely sampled. As with other wavelet transforms, a key advantage it has over Fourier transforms is temporal resolution: it captures both frequency and location information. The accuracy of the joint time-frequency resolution is limited by the uncertainty principle of time-frequency. Empirical mode decomposition is based on decomposition signal into intrinsic mode functions (IMFs). IMFs are quasiharmonical oscillations that are extracted from

1794-467: Is applicable to both streaming data and static (stored) data. To digitally analyze and manipulate an analog signal, it must be digitized with an analog-to-digital converter (ADC). Sampling is usually carried out in two stages, discretization and quantization . Discretization means that the signal is divided into equal intervals of time, and each interval is represented by a single measurement of amplitude. Quantization means each amplitude measurement

1872-433: Is approximated by a value from a finite set. Rounding real numbers to integers is an example. The Nyquist–Shannon sampling theorem states that a signal can be exactly reconstructed from its samples if the sampling frequency is greater than twice the highest frequency component in the signal. In practice, the sampling frequency is often significantly higher than this. It is common to use an anti-aliasing filter to limit

1950-504: Is closely related to nonlinear system identification and can be implemented in the time , frequency , and spatio-temporal domains . The application of digital computation to signal processing allows for many advantages over analog processing in many applications, such as error detection and correction in transmission as well as data compression . Digital signal processing is also fundamental to digital technology , such as digital telecommunication and wireless communications . DSP

2028-915: Is done by additional third-party DSP chips located on extension cards or external hardware boxes or racks. Many digital audio workstations such as Logic Pro , Cubase , Digital Performer and Pro Tools LE use native processing. Others, such as Pro Tools HD, Universal Audio 's UAD-1 and TC Electronic 's Powercore use DSP processing. General application areas for DSP include Specific examples include speech coding and transmission in digital mobile phones , room correction of sound in hi-fi and sound reinforcement applications, analysis and control of industrial processes , medical imaging such as CAT scans and MRI , audio crossovers and equalization , digital synthesizers , and audio effects units . DSP has been used in hearing aid technology since 1996, which allows for automatic directional microphones, complex digital noise reduction , and improved adjustment of

2106-489: Is just 1 + α 2 {\displaystyle {\sqrt {1+\alpha ^{2}}}} in units of N ( DFT "bins" ). As α increases, the main lobe increases in width, and the side lobes decrease in amplitude.  α  = 0 corresponds to a rectangular window. For large α, the shape of the Kaiser window (in both time and frequency domain) tends to a Gaussian curve.  The Kaiser window

2184-469: Is nearly optimal in the sense of its peak's concentration around frequency 0. {\displaystyle 0.} A related window function is the Kaiser–Bessel-derived (KBD) window, which is designed to be suitable for use with the modified discrete cosine transform (MDCT). The KBD window function is defined in terms of the Kaiser window of length N +1, by the formula : This defines

2262-481: Is not observed in modern devices, for example, at the 65 nm technology node. For low noise at narrow bandwidth , the higher input resistance of the FET is advantageous. FETs are divided into two families: junction FET ( JFET ) and insulated gate FET (IGFET). The IGFET is more commonly known as a metal–oxide–semiconductor FET ( MOSFET ), reflecting its original construction from layers of metal (the gate), oxide (the insulation), and semiconductor. Unlike IGFETs,

2340-421: Is often easier and cheaper to use a standard microcontroller and write a computer program to carry out a control function than to design an equivalent mechanical system. A transistor can use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals, a property called gain . It can produce a stronger output signal, a voltage or current, proportional to

2418-585: Is one of the most widely used software tools for DSP. It offers a high-level programming environment with built-in functions for signal processing, making it accessible for both beginners and experts. MATLAB is used for research, algorithm development, and prototyping in various fields such as telecommunications, audio processing, and biomedical engineering. Python is an open-source programming language that has gained popularity in scientific computing. Libraries such as NumPy and SciPy extend Python’s capabilities for numerical computations and signal processing. Python

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2496-541: Is particularly useful for educational purposes, allowing students to learn DSP concepts without the cost of MATLAB. For high-performance DSP applications, C and C++ are often used, especially when low-level control over hardware is required. Libraries such as Intel’s IPP (Integrated Performance Primitives) and ARM’s CMSIS-DSP provide optimized functions for signal processing. C/C++ is used in applications requiring real-time processing, such as telecommunications, embedded systems, and video processing. Digital signal processing

2574-401: Is processing digital photographs with software such as Photoshop . When the application requirement is real-time, DSP is often implemented using specialized or dedicated processors or microprocessors, sometimes using multiple processors or multiple processing cores. These may process data using fixed-point arithmetic or floating point. For more demanding applications FPGAs may be used. For

2652-400: Is the use of digital processing , such as by computers or more specialized digital signal processors , to perform a wide variety of signal processing operations. The digital signals processed in this manner are a sequence of numbers that represent samples of a continuous variable in a domain such as time, space, or frequency. In digital electronics , a digital signal is represented as

2730-514: Is widely used in research, machine learning, and data analysis, making it suitable for DSP applications in various domains. LabVIEW (Laboratory Virtual Instrument Engineering Workbench) is a system-design platform and development environment from National Instruments. It is particularly popular in industry for automated testing and measurement. LabVIEW is commonly used in embedded systems, instrumentation, and control systems, particularly in industries like telecommunications and automotive. GNU Radio

2808-455: The cepstrum converts a signal to the frequency domain through Fourier transform, takes the logarithm, then applies another Fourier transform. This emphasizes the harmonic structure of the original spectrum. Digital filters come in both infinite impulse response (IIR) and finite impulse response (FIR) types. Whereas FIR filters are always stable, IIR filters have feedback loops that may become unstable and oscillate. The Z-transform provides

2886-530: The frequency response . Digital Signal Processing (DSP) involves the manipulation of signals after they have been converted into a digital format. This field is supported by a variety of software tools that enable engineers, researchers, and hobbyists to design, analyze, and implement DSP algorithms. This article explores some of the most popular software tools used in DSP, highlighting their features, advantages, and common applications. MATLAB (Matrix Laboratory)

2964-546: The metal–oxide–semiconductor field-effect transistor (MOSFET), the MOSFET was invented at Bell Labs between 1955 and 1960. Transistors revolutionized the field of electronics and paved the way for smaller and cheaper radios , calculators , computers , and other electronic devices. Most transistors are made from very pure silicon , and some from germanium , but certain other semiconductor materials are sometimes used. A transistor may have only one kind of charge carrier in

3042-399: The surface state barrier that prevented the external electric field from penetrating the material. In 1955, Carl Frosch and Lincoln Derick accidentally grew a layer of silicon dioxide over the silicon wafer, for which they observed surface passivation effects. By 1957 Frosch and Derick, using masking and predeposition, were able to manufacture silicon dioxide field effect transistors;

3120-412: The MOSFET made it possible to build high-density integrated circuits, allowing the integration of more than 10,000 transistors in a single IC. Bardeen and Brattain's 1948 inversion layer concept forms the basis of CMOS technology today. The CMOS (complementary MOS ) was invented by Chih-Tang Sah and Frank Wanlass at Fairchild Semiconductor in 1963. The first report of a floating-gate MOSFET

3198-775: The Regency Division of Industrial Development Engineering Associates, I.D.E.A. and Texas Instruments of Dallas, Texas, the TR-1 was manufactured in Indianapolis, Indiana. It was a near pocket-sized radio with four transistors and one germanium diode. The industrial design was outsourced to the Chicago firm of Painter, Teague and Petertil. It was initially released in one of six colours: black, ivory, mandarin red, cloud grey, mahogany and olive green. Other colours shortly followed. The first production all-transistor car radio

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3276-531: The abstract process of sampling . Numerical methods require a quantized signal, such as those produced by an ADC. The processed result might be a frequency spectrum or a set of statistics. But often it is another quantized signal that is converted back to analog form by a digital-to-analog converter (DAC). DSP engineers usually study digital signals in one of the following domains: time domain (one-dimensional signals), spatial domain (multidimensional signals), frequency domain , and wavelet domains. They choose

3354-431: The analysis of signals with respect to time. Similarly, space domain refers to the analysis of signals with respect to position, e.g., pixel location for the case of image processing. The most common processing approach in the time or space domain is enhancement of the input signal through a method called filtering. Digital filtering generally consists of some linear transformation of a number of surrounding samples around

3432-431: The basis of modern digital electronics since the late 20th century, paving the way for the digital age . The US Patent and Trademark Office calls it a "groundbreaking invention that transformed life and culture around the world". Its ability to be mass-produced by a highly automated process ( semiconductor device fabrication ), from relatively basic materials, allows astonishingly low per-transistor costs. MOSFETs are

3510-404: The body is connected to the source inside the package, and this will be assumed for the following description. In a FET, the drain-to-source current flows via a conducting channel that connects the source region to the drain region. The conductivity is varied by the electric field that is produced when a voltage is applied between the gate and source terminals, hence the current flowing between

3588-437: The collector to the emitter. If the voltage difference between the collector and emitter were zero (or near zero), the collector current would be limited only by the load resistance (light bulb) and the supply voltage. This is called saturation because the current is flowing from collector to emitter freely. When saturated, the switch is said to be on . The use of bipolar transistors for switching applications requires biasing

3666-593: The components of signal. Components are assumed to be complex decaying exponents. A time-frequency representation of signal can capture both temporal evolution and frequency structure of analyzed signal. Temporal and frequency resolution are limited by the principle of uncertainty and the tradeoff is adjusted by the width of analysis window. Linear techniques such as Short-time Fourier transform , wavelet transform , filter bank , non-linear (e.g., Wigner–Ville transform ) and autoregressive methods (e.g. segmented Prony method) are used for representation of signal on

3744-455: The concept of a field-effect transistor (FET) in 1926, but it was not possible to construct a working device at that time. The first working device was a point-contact transistor invented in 1947 by physicists John Bardeen , Walter Brattain , and William Shockley at Bell Labs who shared the 1956 Nobel Prize in Physics for their achievement. The most widely used type of transistor is

3822-445: The concept of an inversion layer, forms the basis of CMOS and DRAM technology today. In the early years of the semiconductor industry , companies focused on the junction transistor , a relatively bulky device that was difficult to mass-produce , limiting it to several specialized applications. Field-effect transistors (FETs) were theorized as potential alternatives, but researchers could not get them to work properly, largely due to

3900-449: The controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more in miniature form are found embedded in integrated circuits . Because transistors are the key active components in practically all modern electronics , many people consider them one of the 20th century's greatest inventions. Physicist Julius Edgar Lilienfeld proposed

3978-559: The current in the base. Because the base and emitter connections behave like a semiconductor diode, a voltage drop develops between them. The amount of this drop, determined by the transistor's material, is referred to as V BE . (Base Emitter Voltage) Transistors are commonly used in digital circuits as electronic switches which can be either in an "on" or "off" state, both for high-power applications such as switched-mode power supplies and for low-power applications such as logic gates . Important parameters for this application include

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4056-465: The current sample of the input or output signal. The surrounding samples may be identified with respect to time or space. The output of a linear digital filter to any given input may be calculated by convolving the input signal with an impulse response . Signals are converted from time or space domain to the frequency domain usually through use of the Fourier transform . The Fourier transform converts

4134-456: The current switched, the voltage handled, and the switching speed, characterized by the rise and fall times . In a switching circuit, the goal is to simulate, as near as possible, the ideal switch having the properties of an open circuit when off, the short circuit when on, and an instantaneous transition between the two states. Parameters are chosen such that the "off" output is limited to leakage currents too small to affect connected circuitry,

4212-441: The domain in which to process a signal by making an informed assumption (or by trying different possibilities) as to which domain best represents the essential characteristics of the signal and the processing to be applied to it. A sequence of samples from a measuring device produces a temporal or spatial domain representation, whereas a discrete Fourier transform produces the frequency domain representation. Time domain refers to

4290-460: The drain and source is controlled by the voltage applied between the gate and source. As the gate–source voltage ( V GS ) is increased, the drain–source current ( I DS ) increases exponentially for V GS below threshold, and then at a roughly quadratic rate: ( I DS ∝ ( V GS − V T ) , where V T is the threshold voltage at which drain current begins) in the " space-charge-limited " region above threshold. A quadratic behavior

4368-463: The first planar transistors, in which drain and source were adjacent at the same surface. They showed that silicon dioxide insulated, protected silicon wafers and prevented dopants from diffusing into the wafer. After this, J.R. Ligenza and W.G. Spitzer studied the mechanism of thermally grown oxides, fabricated a high quality Si/ SiO 2 stack and published their results in 1960. Following this research, Mohamed Atalla and Dawon Kahng proposed

4446-454: The following limitations: Transistors are categorized by Hence, a particular transistor may be described as silicon, surface-mount, BJT, NPN, low-power, high-frequency switch . Convenient mnemonic to remember the type of transistor (represented by an electrical symbol ) involves the direction of the arrow. For the BJT , on an n-p-n transistor symbol, the arrow will " N ot P oint i N" . On

4524-450: The idea of a field-effect transistor that used an electric field as a "grid" was not new. Instead, what Bardeen, Brattain, and Shockley invented in 1947 was the first point-contact transistor . To acknowledge this accomplishment, Shockley, Bardeen and Brattain jointly received the 1956 Nobel Prize in Physics "for their researches on semiconductors and their discovery of the transistor effect". Shockley's team initially attempted to build

4602-418: The inventions of the junction transistor in 1948 and the MOSFET in 1959. The MOSFET is by far the most widely used transistor, in applications ranging from computers and electronics to communications technology such as smartphones . It has been considered the most important transistor, possibly the most important invention in electronics, and the device that enabled modern electronics. It has been

4680-613: The mechanical encoding from punched metal cards. The first prototype pocket transistor radio was shown by INTERMETALL, a company founded by Herbert Mataré in 1952, at the Internationale Funkausstellung Düsseldorf from August 29 to September 6, 1953. The first production-model pocket transistor radio was the Regency TR-1 , released in October 1954. Produced as a joint venture between

4758-409: The most demanding applications or high-volume products, ASICs might be designed specifically for the application. Parallel implementations of DSP algorithms, utilising multi-core CPU and many-core GPU architectures, are developed to improve the performances in terms of latency of these algorithms. Native processing is done by the computer's CPU rather than by DSP or outboard processing, which

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4836-927: The most numerously produced artificial objects in history, with more than 13 sextillion manufactured by 2018. Although several companies each produce over a billion individually packaged (known as discrete ) MOS transistors every year, the vast majority are produced in integrated circuits (also known as ICs , microchips, or simply chips ), along with diodes , resistors , capacitors and other electronic components , to produce complete electronic circuits. A logic gate consists of up to about 20 transistors, whereas an advanced microprocessor , as of 2022, may contain as many as 57 billion MOSFETs. Transistors are often organized into logic gates in microprocessors to perform computation. The transistor's low cost, flexibility and reliability have made it ubiquitous. Transistorized mechatronic circuits have replaced electromechanical devices in controlling appliances and machinery. It

4914-548: The potential in this, and over the next few months worked to greatly expand the knowledge of semiconductors . The term transistor was coined by John R. Pierce as a contraction of the term transresistance . According to Lillian Hoddeson and Vicki Daitch, Shockley proposed that Bell Labs' first patent for a transistor should be based on the field-effect and that he be named as the inventor. Having unearthed Lilienfeld's patents that went into obscurity years earlier, lawyers at Bell Labs advised against Shockley's proposal because

4992-405: The resistance of the transistor in the "on" state is too small to affect circuitry, and the transition between the two states is fast enough not to have a detrimental effect. In a grounded-emitter transistor circuit, such as the light-switch circuit shown, as the base voltage rises, the emitter and collector currents rise exponentially. The collector voltage drops because of reduced resistance from

5070-444: The signal bandwidth to comply with the sampling theorem, however careful selection of this filter is required because the reconstructed signal will be the filtered signal plus residual aliasing from imperfect stop band rejection instead of the original (unfiltered) signal. Theoretical DSP analyses and derivations are typically performed on discrete-time signal models with no amplitude inaccuracies ( quantization error ), created by

5148-556: The signal. DSP algorithms may be run on general-purpose computers and digital signal processors . DSP algorithms are also implemented on purpose-built hardware such as application-specific integrated circuit (ASICs). Additional technologies for digital signal processing include more powerful general purpose microprocessors , graphics processing units , field-programmable gate arrays (FPGAs), digital signal controllers (mostly for industrial applications such as motor control), and stream processors . For systems that do not have

5226-405: The time or space information to a magnitude and phase component of each frequency. With some applications, how the phase varies with frequency can be a significant consideration. Where phase is unimportant, often the Fourier transform is converted to the power spectrum, which is the magnitude of each frequency component squared. The most common purpose for analysis of signals in the frequency domain

5304-422: The time-frequency plane. Non-linear and segmented Prony methods can provide higher resolution, but may produce undesirable artifacts. Time-frequency analysis is usually used for analysis of non-stationary signals. For example, methods of fundamental frequency estimation, such as RAPT and PEFAC are based on windowed spectral analysis. In numerical analysis and functional analysis , a discrete wavelet transform

5382-409: The transistor so that it operates between its cut-off region in the off-state and the saturation region ( on ). This requires sufficient base drive current. As the transistor provides current gain, it facilitates the switching of a relatively large current in the collector by a much smaller current into the base terminal. The ratio of these currents varies depending on the type of transistor, and even for

5460-483: The transistor, the company rushed to get its "transistron" into production for amplified use in France's telephone network, filing his first transistor patent application on August 13, 1948. The first bipolar junction transistors were invented by Bell Labs' William Shockley, who applied for patent (2,569,347) on June 26, 1948. On April 12, 1950, Bell Labs chemists Gordon Teal and Morgan Sparks successfully produced

5538-486: The triode. He filed identical patents in the United States in 1926 and 1928. However, he did not publish any research articles about his devices nor did his patents cite any specific examples of a working prototype. Because the production of high-quality semiconductor materials was still decades away, Lilienfeld's solid-state amplifier ideas would not have found practical use in the 1920s and 1930s, even if such

5616-408: The widespread adoption of transistor radios. Seven million TR-63s were sold worldwide by the mid-1960s. Sony's success with transistor radios led to transistors replacing vacuum tubes as the dominant electronic technology in the late 1950s. The first working silicon transistor was developed at Bell Labs on January 26, 1954, by Morris Tanenbaum . The first production commercial silicon transistor

5694-525: Was a few ten-thousandths of an inch thick. Indium electroplated into the depressions formed the collector and emitter. AT&T first used transistors in telecommunications equipment in the No. 4A Toll Crossbar Switching System in 1953, for selecting trunk circuits from routing information encoded on translator cards. Its predecessor, the Western Electric No. 3A phototransistor , read

5772-486: Was announced by Texas Instruments in May 1954. This was the work of Gordon Teal , an expert in growing crystals of high purity, who had previously worked at Bell Labs. The basic principle of the field-effect transistor (FET) was first proposed by physicist Julius Edgar Lilienfeld when he filed a patent for a device similar to MESFET in 1926, and for an insulated-gate field-effect transistor in 1928. The FET concept

5850-521: Was developed by Chrysler and Philco corporations and was announced in the April 28, 1955, edition of The Wall Street Journal . Chrysler made the Mopar model 914HR available as an option starting in fall 1955 for its new line of 1956 Chrysler and Imperial cars, which reached dealership showrooms on October 21, 1955. The Sony TR-63, released in 1957, was the first mass-produced transistor radio, leading to

5928-918: Was independently invented by physicists Herbert Mataré and Heinrich Welker while working at the Compagnie des Freins et Signaux Westinghouse , a Westinghouse subsidiary in Paris . Mataré had previous experience in developing crystal rectifiers from silicon and germanium in the German radar effort during World War II . With this knowledge, he began researching the phenomenon of "interference" in 1947. By June 1948, witnessing currents flowing through point-contacts, he produced consistent results using samples of germanium produced by Welker, similar to what Bardeen and Brattain had accomplished earlier in December 1947. Realizing that Bell Labs' scientists had already invented

6006-455: Was later also theorized by engineer Oskar Heil in the 1930s and by William Shockley in the 1940s. In 1945 JFET was patented by Heinrich Welker . Following Shockley's theoretical treatment on JFET in 1952, a working practical JFET was made in 1953 by George C. Dacey and Ian M. Ross . In 1948, Bardeen and Brattain patented the progenitor of MOSFET at Bell Labs, an insulated-gate FET (IGFET) with an inversion layer. Bardeen's patent, and

6084-521: Was made by Dawon Kahng and Simon Sze in 1967. In 1967, Bell Labs researchers Robert Kerwin, Donald Klein and John Sarace developed the self-aligned gate (silicon-gate) MOS transistor, which Fairchild Semiconductor researchers Federico Faggin and Tom Klein used to develop the first silicon-gate MOS integrated circuit . A double-gate MOSFET was first demonstrated in 1984 by Electrotechnical Laboratory researchers Toshihiro Sekigawa and Yutaka Hayashi. The FinFET (fin field-effect transistor),

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