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Acoustical Measurements And Instrumentation
Analysis of sound and acoustics plays a role in such engineering tasks as product design, production test, machine performance, and process control. For instance, product design can require modification of sound level or noise for compliance with standards from ANSI, IEC, and ISO. The work might also involve design fine-tuning to meet market expectations. Here, examples include tweaking an automobile door latching mechanism to impress a consumer with a satisfying click or modifying an exhaust manifold to change the tone of an engine's rumble. Aircraft designers are also using acoustic instrumentation to reduce the noise generated on takeoff and landing. Acoustical measurements and instrumentation range from a handheld sound level meter to a 1000-microphone phased array. Components Most of the acoustical measurement and instrumentation systems can be broken down into three components: sensors, data acquisition and analysis. Sensors The most common sensor used for acoustic me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American National Standards Institute
The American National Standards Institute (ANSI ) is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international standards so that American products can be used worldwide. ANSI accredits standards that are developed by representatives of other standards organizations, government agencies, consumer groups, companies, and others. These standards ensure that the characteristics and performance of products are consistent, that people use the same definitions and terms, and that products are tested the same way. ANSI also accredits organizations that carry out product or personnel certification in accordance with requirements defined in international standards. The organization's headquarters are in Washington, D.C. ANSI's operations office is located in New York City. The ANSI annual operating b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Electrotechnical Commission
The International Electrotechnical Commission (IEC; in French: ''Commission électrotechnique internationale'') is an international standards organization that prepares and publishes international standards for all electrical, electronic and related technologies – collectively known as "electrotechnology". IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology and marine energy as well as many others. The IEC also manages four global conformity assessment systems that certify whether equipment, system or components conform to its international standards. All electrotechnologies are covered by IEC Standards, including energy production and distribution, electronics, magnetics and electromagnetics, electroacoustics, multimedia, telecommunication and medical technology, as well as associated general disciplines such as t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Organization For Standardization
The International Organization for Standardization (ISO ) is an international standard development organization composed of representatives from the national standards organizations of member countries. Membership requirements are given in Article 3 of the ISO Statutes. ISO was founded on 23 February 1947, and (as of November 2022) it has published over 24,500 international standards covering almost all aspects of technology and manufacturing. It has 809 Technical committees and sub committees to take care of standards development. The organization develops and publishes standardization in all technical and nontechnical fields other than electrical and electronic engineering, which is handled by the IEC.Editors of Encyclopedia Britannica. 3 June 2021.International Organization for Standardization" ''Encyclopedia Britannica''. Retrieved 2022-04-26. It is headquartered in Geneva, Switzerland, and works in 167 countries . The three official languages of the ISO are English, Fren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microphone
A microphone, colloquially called a mic or mike (), is a transducer that converts sound into an electrical signal. Microphones are used in many applications such as telephones, hearing aids, public address systems for concert halls and public events, motion picture production, live and recorded audio engineering, sound recording, two-way radios, megaphones, and radio and television broadcasting. They are also used in computers for recording voice, speech recognition, VoIP, and for other purposes such as ultrasonic sensors or knock sensors. Several types of microphone are used today, which employ different methods to convert the air pressure variations of a sound wave to an electrical signal. The most common are the dynamic microphone, which uses a coil of wire suspended in a magnetic field; the condenser microphone, which uses the vibrating diaphragm as a capacitor plate; and the contact microphone, which uses a crystal of piezoelectric material. Microphones typically n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophones
A hydrophone ( grc, ὕδωρ + φωνή, , water + sound) is a microphone designed to be used underwater for recording or listening to underwater sound. Most hydrophones are based on a piezoelectric transducer that generates an electric potential when subjected to a pressure change, such as a sound wave. Some piezoelectric transducers can also serve as a sound projector, but not all have this capability, and some may be destroyed if used in such a manner. A hydrophone can detect airborne sounds, but will be insensitive because it is designed to match the acoustic impedance of water, a denser fluid than air. Sound travels 4.3 times faster in water than in air, and a sound wave in water exerts a pressure 60 times that exerted by a wave of the same amplitude in air. Similarly, a standard microphone can be buried in the ground, or immersed in water if it is put in a waterproof container, but will give poor performance due to the similarly bad acoustic impedance match. History The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accelerometers
An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.81 m/s2) will measure zero. Accelerometers have many uses in industry and science. Highly sensitive accelerometers are used in inertial navigation systems for aircraft and missiles. Vibration in rotating machines is monitored by accelerometers. They are used in tablet computers and digital cameras so that images on screens are always displayed upright. In unmanned aerial vehicles, accelerometers help to stabilise flight. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PCB Piezotronics
PCB Piezotronics is a manufacturer of piezoelectric sensors. The name ''"PCB"'' is abbreviation for "PicoCoulomB" which is technical terminology defining an electrical charge of the type generated by the piezoelectric sensors they manufacture. It is also a registered trademark of the company. "Piezotronics" combines the science of Piezoelectricity and electronics. PCB® manufactures sensors and related instrumentation. Sensors are small electromechanical instruments for the measurement of acceleration, dynamic pressure, force, acoustics, torque, load, strain, shock, vibration and sound. __TOC__ History Founded by Robert W. Lally and James (Jim) F. Lally in 1967, PCB Piezotronics has evolved from a family business to a large company engineering and manufacturing operation, with technical emphasis on the incorporation of integrated circuit-piezoelectric sensor technology. In 1967 the integrated circuit piezoelectric sensor, also known as ICP sensors, incorporated microe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brüel & Kjær
Brüel & Kjær (Sound and Vibration Measurement A/S) was a Danish multinational engineering and electronics company headquartered in Nærum, near Copenhagen. It was the largest producer in the world of equipment for acoustic and vibrational measurements Brüel & Kjær is a subsidiary of Spectris. Brüel & Kjær was founded by Per Vilhelm Brüel (6 March 1915 – 2 April 2015) and Viggo Kjær (5 June 1914 – 25 July 2013) on 28 November 1942. The two men met while studying at The Polytechnic School in Copenhagen (now the Technical University of Denmark). After receiving their M.S. degrees in 1939 they decided to start a company developing instruments for acoustic measurements. Holger Nielsen joined the company as third partner in 1945, and was with the company until his death in 1978. Products The most notable products and technologies developed by the company include: *1940s – Precision measurement instruments including radio frequency analyzers and Geiger counters. Typ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analog-to-digital Converter
In electronics, an analog-to-digital converter (ADC, A/D, or A-to-D) is a system that converts an analog signal, such as a sound picked up by a microphone or light entering a digital camera, into a digital signal. An ADC may also provide an isolated measurement such as an electronic device that converts an analog input voltage or current to a digital number representing the magnitude of the voltage or current. Typically the digital output is a two's complement binary number that is proportional to the input, but there are other possibilities. There are several ADC architectures. Due to the complexity and the need for precisely matched components, all but the most specialized ADCs are implemented as integrated circuits (ICs). These typically take the form of metal–oxide–semiconductor (MOS) mixed-signal integrated circuit chips that integrate both analog and digital circuits. A digital-to-analog converter (DAC) performs the reverse function; it converts a digital signa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-aliasing Filter
An anti-aliasing filter (AAF) is a filter used before a signal sampler to restrict the bandwidth of a signal to satisfy the Nyquist–Shannon sampling theorem over the band of interest. Since the theorem states that unambiguous reconstruction of the signal from its samples is possible when the power of frequencies above the Nyquist frequency is zero, a brick wall filter is an idealized but impractical AAF. A practical AAF makes a trade off between reduced bandwidth and increased aliasing. A practical anti-aliasing filter will typically permit some aliasing to occur or attenuate or otherwise distort some in-band frequencies close to the Nyquist limit. For this reason, many practical systems sample higher than would be theoretically required by a perfect AAF in order to ensure that all frequencies of interest can be reconstructed, a practice called oversampling. Optical applications The Pentax K-3 from Ricoh introduced a unique sensor-based anti-aliasing filter. The filter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynamic Range
Dynamic range (abbreviated DR, DNR, or DYR) is the ratio between the largest and smallest values that a certain quantity can assume. It is often used in the context of signals, like sound and light. It is measured either as a ratio or as a base-10 ( decibel) or base-2 (doublings, bits or stops) logarithmic value of the difference between the smallest and largest signal values. Electronically reproduced audio and video is often processed to fit the original material with a wide dynamic range into a narrower recorded dynamic range that can more easily be stored and reproduced; this processing is called dynamic range compression. Human perception The human senses of sight and hearing have a relatively high dynamic range. However, a human cannot perform these feats of perception at both extremes of the scale at the same time. The human eye takes time to adjust to different light levels, and its dynamic range in a given scene is actually quite limited due to optical glare. The ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smaart
Smaart (System Measurement Acoustical Analysis in Real Time) is a suite of audio and acoustical measurements and instrumentation software tools introduced in 1996 by JBL's professional audio division. It is designed to help the live sound engineer optimize sound reinforcement systems before public performance and actively monitor acoustical parameters in real time while an audio system is in use. Most earlier analysis systems required specific test signals sent through the sound system, ones that would be unpleasant for the audience to hear. Smaart is a source-independent analyzer and therefore will work effectively with a variety of test signals including speech or music. The product has been known as JBL-SMAART, SIA-SMAART Pro, EAW SMAART, and SmaartLive. As of 2008 the product has been branded as simply Smaart. An acoustician version has been offered as Smaart Acoustic Tools, however as of Smaart v7.4, Acoustic Tools have been included within the Impulse Response mode of Smaa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
