##
complex tone

Overview page. Subjects: Psychology.

A sound wave composed of a number of pure tones of different frequencies (1). See also Fourier analysis, harmonic, overtone, partial tone, tone (1).

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fast Fourier transform

Overview page. Subjects: Earth Sciences and Geography — Probability and Statistics.

(FFT)

An algorithm (e.g. the Cooley–Tukey method) which enables the Fourier transformation of digitized wave-forms to be accomplished more rapidly by computer than would be...

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filtering

Overview page. Subjects: Computing.

**time...**

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Fourier series

Overview page. Subjects: Chemistry.

An expansion of a periodic function as a series of trigonometric functions. Thus,f(*x*) = *a*
_{0}+(*a*
_{1}cos*x*+*b*
_{1}sin*x*)+(*a*
_{2}cos2*x*+*b*
_{2}sin2*x*)...

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Fourier theorem

Overview page. Subjects: Psychology.

A mathematical proof that any periodic function can be decomposed by Fourier analysis into a Fourier series that is a sum of sine and cosine terms with suitable constants.

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Fourier transform

Overview page. Subjects: Computing.

If f is a function of the real variable *x*, its Fourier transform F is defined by , where i=√−1 and *t* is a real variable. The inverse Fourier transform is given by .

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hearing

Overview page. Subjects: Zoology and Animal Sciences.

The sense by which sound is detected. In vertebrates the organ of hearing is the ear. In higher vertebrates variation in air pressure caused by sound waves are amplified in the outer and...

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Ohm's acoustic law

Overview page. Subjects: Psychology.

The proposition that the human auditory system responds to a complex sound by generating sensations of the separate components of the sound rather than a sensation of a single integrated...

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partial tone

Overview page. Subjects: Psychology.

Any pure tone that is a component of a complex tone. Also called a *partial*. See also Fourier analysis.

##
pure tone

Overview page. Subjects: Psychology.

A sound wave such as that generated by a tuning fork or oscillator whose pressure variation as a function of time is a sine wave. Also called a *simple tone*. See also Fourier analysis, tone...

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signature

Overview page. Subjects: Earth Sciences and Geography.

The characteristics of geophysical anomalies within a region or along a profile. It is often based on Fourier or power-spectrum analyses of either gravity (gravity signature) or magnetic...

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spatial frequency

Overview page. Subjects: Earth Sciences and Geography — Psychology.

The inverse of the wavelength in a visual image that has been transformed into a sinusoidal grating of varying luminance, a high spatial frequency capturing fine detail and a low spatial...

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speech recognition

Overview page. Subjects: Computing — Psychology.

The process of recognizing elements of speech by analysis of the acoustic signal. Many systems may be trained to a particular operator's voice and can build up dictionaries/vocabularies to...

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time series analysis

Overview page. Subjects: Social Sciences — Environmental Science.

A set of statistical procedures for analysing time series. See ARIMA, autocorrelation, autoregression, correlogram, Fourier analysis, moving average. See also aliasing, interrupted...