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Telecoil
A hearing aid is a device designed to improve hearing by making sound audible to a person with hearing loss. Hearing aids are classified as medical devices in most countries, and regulated by the respective regulations. Small audio amplifiers such as personal sound amplification products (PSAPs) or other plain sound reinforcing systems cannot be sold as "hearing aids". Early devices, such as ear trumpets or ear horns, were passive amplification cones designed to gather sound energy and direct it into the ear canal. Modern devices are computerised electroacoustic systems that transform environmental sound to make it audible, according to audiometrical and cognitive rules. Modern devices also utilize sophisticated digital signal processing, aiming to improve speech intelligibility and comfort for the user. Such signal processing includes feedback management, wide dynamic range compression, directionality, frequency lowering, and noise reduction. Modern hearing aids require ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlear Implant
A cochlear implant (CI) is a surgically implanted Neuroprosthetics, neuroprosthesis that provides a person who has moderate-to-profound sensorineural hearing loss with sound perception. With the help of therapy, cochlear implants may allow for improved speech understanding in both quiet and noisy environments. A CI bypasses acoustic hearing by direct electrical stimulation of the auditory nerve. Through everyday listening and auditory training, cochlear implants allow both children and adults to learn to interpret those signals as speech and sound. The implant has two main components. The outside component is generally worn behind the ear, but could also be attached to clothing, for example, in young children. This component, the sound processor, contains microphones, electronics that include digital signal processor (DSP) chips, battery, and a coil that transmits a signal to the implant across the skin. The inside component, the actual implant, has a coil to receive signals, elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hearing Loss
Hearing loss is a partial or total inability to hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to acquire spoken language, and in adults it can create difficulties with social interaction and at work. Hearing loss can be temporary or permanent. Hearing loss related to age usually affects both ears and is due to cochlear hair cell loss. In some people, particularly older people, hearing loss can result in loneliness. Hearing loss may be caused by a number of factors, including: genetics, ageing, exposure to noise, some infections, birth complications, trauma to the ear, and certain medications or toxins. A common condition that results in hearing loss is chronic ear infections. Certain infections during pregnancy, such as cytomegalovirus, syphilis and rubella, may also cause hearing loss in the child. Hearing loss is diagnosed when hearing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Occlusion Effect
The occlusion effect occurs when an object fills the outer portion of a person's ear canal, causing that person to perceive echo-like "hollow" or "booming" sounds generated from their voice, chewing, footsteps, or any other sounds originating in their own body. The bone-conducted sound travels to the cochlea through different pathways. The outer ear pathway corresponds to the sound pressure generated in the ear canal cavity due to the vibration of the ear canal wall, which constitutes the source of the occlusion effect. At low frequencies, the outer ear pathway is negligible when the ear canal is open but dominates when the ear canal is occluded. The occlusion effect is thus objectively characterized by an acoustic pressure increase in the occluded ear canal at low frequencies and which can be measured with a probe-tube microphone. Considering that the vibrating ear canal wall acts as an ideal source of volume velocity (also known as volumetric flow rate), the occlusion device inc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Emerging Markets
An emerging market (or an emerging country or an emerging economy) is a market that has some characteristics of a developed market, but does not fully meet its standards. This includes markets that may become developed markets in the future or were in the past. The term "frontier market" is used for Developing country, developing countries with smaller, riskier, or more illiquid capital markets than "emerging". As of 2006, the economies of Economy of China, China and Economy of India, India are considered to be the largest emerging markets. According to ''The Economist'', many people find the term outdated, but no new term has gained traction. Emerging market hedge fund capital reached a record new level in the first quarter of 2011 of $121 billion. Emerging market economies’ share of global PPP-adjusted GDP has risen from 27 percent in 1960 to around 53 percent by 2013. The ten largest emerging economies by List of countries by GDP (nominal), nominal GDP are 4 of the 9 BRICS cou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Playing Cards
A playing card is a piece of specially prepared card stock, heavy paper, thin cardboard, plastic-coated paper, cotton-paper blend, or thin plastic that is marked with distinguishing motifs. Often the front (face) and back of each card has a Paper#Finishing, finish to make handling easier. They are most commonly used for playing card games, and are also used in magic tricks, cardistry, card throwing, and house of cards, card houses; cards may also be collected. Playing cards are typically palm-sized for convenient handling, and usually are sold together in a set as a deck of cards or pack of cards. The most common type of playing card in the West is the French-suited, standard 52-card pack, of which the most widespread design is the English pattern, followed by the Belgian-Genoese pattern. However, many countries use other, traditional types of playing card, including those that are German-suited, German, Italian-suited, Italian, Spanish-suited, Spanish and Swiss-suited. Tarot ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loudspeaker
A loudspeaker (commonly referred to as a speaker or, more fully, a speaker system) is a combination of one or more speaker drivers, an enclosure, and electrical connections (possibly including a crossover network). The speaker driver is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. The driver is a linear motor connected to a diaphragm, which transmits the motor's movement to produce sound by moving air. An audio signal, typically originating from a microphone, recording, or radio broadcast, is electronically amplified to a power level sufficient to drive the motor, reproducing the sound corresponding to the original unamplified signal. This process functions as the inverse of a microphone. In fact, the ''dynamic speaker'' driver—the most common type—shares the same basic configuration as a dynamic microphone, which operates in reverse as a generator. The dynamic speaker was invented in 1925 by Edward W. Kellogg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Battery (electricity)
An electric battery is a source of electric power consisting of one or more electrochemical cells with external connections for powering electrical devices. When a battery is supplying power, its positive terminal is the cathode and its negative terminal is the anode. The terminal marked negative is the source of electrons. When a battery is connected to an external electric load, those negatively charged electrons flow through the circuit and reach the positive terminal, thus causing a redox reaction by attracting positively charged ions, or cations. Thus, higher energy reactants are converted to lower energy products, and the free-energy difference is delivered to the external circuit as electrical energy. Historically the term "battery" specifically referred to a device composed of multiple cells; however, the usage has evolved to include devices composed of a single cell. Primary (single-use or "disposable") batteries are used once and discarded, as the electrode mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplifier
An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It is a two-port electronic circuit that uses electric power from a power supply to increase the amplitude (magnitude of the voltage or current) of a signal applied to its input terminals, producing a proportionally greater amplitude signal at its output. The amount of amplification provided by an amplifier is measured by its gain: the ratio of output voltage, current, or power to input. An amplifier is defined as a circuit that has a power gain greater than one. An amplifier can be either a separate piece of equipment or an electrical circuit contained within another device. Amplification is fundamental to modern electronics, and amplifiers are widely used in almost all electronic equipment. Amplifiers can be categorized in different ways. One is by the frequency of the electronic signal being amplified. For ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Earmold
An earmold (also spelled; ear mold, ear mould or earmould) is a device worn inserted into the ear for sound conduction or Hearing protection device, hearing protection. Earmolds are anatomically shaped and can be produced in different sizes for general use or specially cast from particular ear forms. Some users specify how hard or soft they want their mold to be, an audiologist can also suggest this. As a conductor, it improves sound transmission to eardrums. This is an essential feature to diminish feedback paths in hearing aids and assure better intelligibility in noisy-environment communication. The main goal in wearing earmolds is to attain better user comfort and efficiency. Earmolds (and their tubes) often turn yellow and stiff with age, and thus need replacement on a regular basis. Traditionally, the job of making earmolds is very time-consuming and skillful; each one is made individually in a molding process. However, new digital ear laser scanners can accelerate this proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Laboratories
Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several laboratories in the United States and around the world. As a former subsidiary of the American Telephone and Telegraph Company (AT&T), Bell Labs and its researchers have been credited with the development of radio astronomy, the transistor, the laser, the photovoltaic cell, the charge-coupled device (CCD), information theory, the Unix operating system, and the programming languages B, C, C++, S, SNOBOL, AWK, AMPL, and others, throughout the 20th century. Eleven Nobel Prizes and five Turing Awards have been awarded for work completed at Bell Laboratories. Bell Labs had its origin in the complex corporate organization of the Bell System telephone conglomerate. The laboratory began operating in the late 19th century as the Wester ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvey Fletcher
Harvey Fletcher (September 11, 1884 – July 23, 1981) was an American physicist. Known as the "father of stereophonic sound", he is credited with the invention of the 2-A audiometer and an early electronic hearing aid. He was an investigator into the nature of speech and hearing, and made contributions in acoustics, electrical engineering, speech, medicine, music, atomic physics, sound pictures, and education. Following his death, he was credited with collaborating with his doctoral advisor, Robert Millikan, on the Nobel-prize winning oil drop experiment which first determined the charge of the electron. Early years Fletcher was born in Provo, Utah. He graduated from Brigham Young High School in 1904. He enrolled at Brigham Young University (BYU), graduating in 1907 with a bachelor's degree. He married Lorena Chipman. They were the parents of seven children. Harvey Fletcher was the father of James C. Fletcher, former president of the University of Utah and NASA Administrator ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
