Glossary of Audio Terminology

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Index | References



object-oriented or object-based programming A software technique in which a system program is expressed completely in terms of predefined things (objects), consisting of a set of variables and operations which can be performed on them, and the connections between objects.

octal A number system using the base-8, i.e., each digit can be any of 8 values, represented by the digits 0-7. Each octal digit can also be represented by a three-bit binary number (since 2E3 =8).

octave 1. Audio. The interval between any two frequencies having a ratio of 2 to 1. 2. Music a. The interval of eight diatonic degrees between two tones, one of which has twice as many vibrations per second as the other. b. A tone that is eight full tones above or below another given tone.

ohm Abbr. Ώ, (Greek upper-case omega). A unit of electrical resistance equal to that of a conductor in which a current of one ampere is produced by a potential of one volt across its terminals. [After Georg Simon Ohm.]

Ohm, Georg Simon (1789-1854) German physicist noted for his contributions to mathematics, acoustics, and the measurement of electrical resistance.

one-bit data converter Loose reference to any of the various data conversion schemes (e.g., delta-sigma, adaptive delta modulation, etc.) that use only one binary bit (i.e., levels 1 and 0) in the conversion and storage process.

one-third octave 1. Term referring to frequencies spaced every one-third of an octave apart. One-third of an octave represents a frequency 1.26-times above a reference, or 0.794-times below the same reference. The math goes like this: 1/3-octave = 2E1/3 = 1.260; and the reciprocal, 1/1.260 = 0.794. Therefore, for example, a frequency 1/3-octave above a 1 kHz reference equals 1.26 kHz (which is rounded-off to the ANSI-ISO preferred frequency of "1.25 kHz" for equalizers and analyzers), while a frequency 1/3-octave below 1 kHz equals 794 Hz (labeled "800 Hz").  2.  Approximates the smallest region (bandwidth) humans reliably detect change. See: critical bands. Compare with: third-octave

op amp (operational amplifier) An analog integrated circuit device characterized as having two opposite polarity inputs and one output, used as the basic building block in analog signal processing.

optical fiber Optical fiber (or "fiber optic") refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic wire or fiber. Optical fiber carries much more information than conventional copper wire and is in general not subject to electromagnetic interference and the need to retransmit signals. Most telephone company long-distance lines are now of optical fiber.

Out-of-Band  Transmission taking place external to the allocated bandwidth for this transmission.  A video conference with out-of-band audio requires a separate telephone conference call to carry the audio.

Overs Term used in digital recording that refers to describe input signals exceeding the full scale range (0 dBFS). It is important to distinguish between 0 dBFS and overs; they are not the same. 0 dBFS is the absolute highest voltage level that any particular A/D can convert. It produces the equivalent of a digital code consisting of all 1s. No digital level can exceed 0 dBFS. A 0 dBFS voltage level and all levels greater than this produce the same output code of all 1s.

oversampling A technique where each sample from the converter is sampled more than once, i.e., oversampled. This multiplication of samples permits digital filtering of the signal, thus reducing the need for sharp analog filters to control aliasing.



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