Engineering

Engine treatment can slash jet noise

There's a song anyone who lives near an airport or directly under the flight path of incoming and departing jets daily wishes they could play: Simon and Garfunkel's "The Sound of Silence."

Electronics & Semiconductors

First electromechanical resonator to operate beyond 100 GHz

In what has the potential to significantly advance wireless communications and mechanical quantum systems, researchers at Yale have demonstrated the world's first electromechanical resonator to operate beyond 100 GHz.

Engineering

Researcher develops new way to measure defects in perovskite

Solar energy is becoming an increasingly popular source of renewable energy. Current solar panels with silicon as their primary component are affordable and reliable. However, the use of a relatively new material, perovskite, ...

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Noise

In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise ("static") heard when listening to a weak radio transmission with significant electrical noise. Signal noise is heard as acoustic noise if the signal is converted into sound (e.g., played through a loudspeaker); it manifests as "snow" on a television or video image. High noise levels can block, distort, change or interfere with the meaning of a message in human, animal and electronic communication.

In signal processing or computing it can be considered random unwanted data without meaning; that is, data that is not being used to transmit a signal, but is simply produced as an unwanted by-product of other activities. "Signal-to-noise ratio" is sometimes used to refer to the ratio of useful to irrelevant information in an exchange.

In biology, noise can describe the variability of a measurement around the mean, for example transcriptional noise describes the variability in gene activity between cells in a population.

In many cases, the special case of thermal noise arises, which sets a fundamental lower limit to what can be measured or signaled and is related to basic physical processes described by thermodynamics, some of which are expressible by simple formulae.

In some fields, noise means unwanted information or data that is not relevant to the hypothesis or theory being investigated or tested.

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