Glossary
of Audio Terminology

objectoriented or objectbased 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 base8, i.e., each digit
can be any of 8 values, represented by the digits 07. Each octal
digit can also be represented by a threebit 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 uppercase 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 (17891854) German physicist noted
for his contributions to mathematics, acoustics, and the measurement
of electrical resistance.
onebit data converter Loose reference to any of the various
data conversion schemes (e.g., deltasigma,
adaptive delta modulation, etc.) that use only one binary bit (i.e.,
levels 1 and 0) in the conversion and storage process.
onethird octave 1. Term
referring to frequencies spaced every onethird of an octave apart.
Onethird of an octave represents a frequency 1.26times above a
reference, or 0.794times below the same reference. The math goes
like this: 1/3octave = 2E1/3 = 1.260; and the reciprocal, 1/1.260
= 0.794. Therefore, for example, a frequency 1/3octave above a
1 kHz reference equals 1.26 kHz (which is roundedoff to the ANSIISO
preferred frequency of "1.25 kHz" for equalizers and analyzers),
while a frequency 1/3octave below 1 kHz equals 794 Hz (labeled
"800 Hz"). 2. Approximates the smallest region
(bandwidth) humans reliably detect change. See: critical
bands. Compare with: thirdoctave
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 longdistance lines are now of
optical fiber.
OutofBand Transmission taking place external to
the allocated bandwidth for this transmission. A video
conference with outofband 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.
