Specifications

EAW Smaart 6 Operation Manual Concepts, Glossary, and Bibliography
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2.2 Glossary of Terms
Analog to Digital (A/D) Conversion: The process of sampling the amplitude of an analog
signal at regular intervals to create a digital representation of the signal.
Amplitude: The size of a real number (e.g., a number of Volts), in either the positive
or negative direction. The term amplitude typically refers to numbers that are not complex
or plotted on a logarithmic scale, such as the numbers stored in the A/D process.
(Numbers expressed logarithmically are more properly called magnitudes.)
Attenuation: A decrease in the level of a signal. Attenuation can refer to reduction in
level for a specified frequency range or a decrease in the overall level.
Coherence: A mathematical function that represents the linearity between two signals.
Coherence is conventionally expressed as a value between 0 and 1. Note that coherence
is affected by measurement conditions and the number of averages used.
Compressors: Electronic devices that cause changes in gain (typically attenuation) as
a function of the input level. These devices should NOT be used when making Frequency
Response measurements as they are nonlinear by nature.
Crosstalk: Undesired energy in one signal (or channel) introduced from an adjacent
signal or channel.
Data Window: A mathematical function used to reduce the negative effects of truncation
that occurs when a finite number of FFT points are used to transform time domain data
into the frequency domain. The Data Window(s) work by reducing the amplitude of the
time domain data at the beginning and end of the FFT data series.
Decay Rate: The rate at which a signal decays (diminishes in magnitude), usually a
function of frequency and expressed in either decibels per second, or relative to the
amount of time that would be required for the signal to decay 60 decibels at the given
rate of decay. (see Reverberation Time)
Decibel: The decibel, often abbreviated as dB, is a logarithmic ratio between two values.
In acoustics, decibels most commonly refer to the ratio of an input level to the output
level of a system, or a given level compared to a fixed reference.
Dynamic Range: The difference in level between the highest and lowest signal a system
can accept or reproduce.
FFT: The Fast Fourier Transform is a mathematical technique used to transform time
domain data into the frequency domain. The term “Fast” refers to the fact that when
the number of time domain samples is a power of 2 (16, 32, 64, 128, 256...) the calcu-
lations can be performed very quickly by a digital computer.