Audio Precision B Series - Technical Terms and Symbols; Abbreviations, Terms, and Symbols Glossary

Abbreviations, Terms and Symbols 29
Abbreviations, Terms and Symbols
used in the following specifications
ADC or A/D . . . . . . . .Analog to Digital converter or conversion.
BW . . . . . . . . . . . . . . .Bandwidth or Measurement Bandwidth, nominally at –3 dB; a single number
indicates only the upper limit.
DAC or D/A . . . . . . . .Digital to Analog converter or conversion.
DSP . . . . . . . . . . . . . . .Digital Signal Processing or Digital Signal Processor.
DUT . . . . . . . . . . . . . .Device Under Test, the device to which the generator or analyzer is connected.
EMC . . . . . . . . . . . . . .Electro-Magnetic Compatibility, usually refers to both emissions (radiated and
conducted via AC mains) and susceptibility.
ENBW . . . . . . . . . . . . .Equivalent Noise Bandwidth, the frequency of an ideal filter having the same rms
response to white noise.
FFT . . . . . . . . . . . . . . .Fast Fourier Transform, a mathematical process converting a signal in the time
domain to the frequency domain.
IMD . . . . . . . . . . . . . . .Inter-Modulation Distortion, a measure of non-linearity using a test signal with
two or more components.
RMS or rms . . . . . . . . .Root Mean Square, an equivalent-power expression of signal amplitude.
SR . . . . . . . . . . . . . . . .Sample Rate, usually as it applies to the conversion rate of A/D and D/A convert-
ers or digital audio formats.
THD . . . . . . . . . . . . . .Total Harmonic Distortion, rms summation of d2 to d9 (may be bandwidth lim-
ited), usually derived from an FFT.
THD+N . . . . . . . . . . . .Rms measurement of ALL harmonics, spurious signals, and noise within a speci-
fied bandwidth.
Typical or Typ . . . . . . .A characteristic that is not guaranteed, usually due to a practical limitation in
testing or metrology.
UI . . . . . . . . . . . . . . . . .Unit Interval, a measure of time is it applies to digital audio formats.
1 UI= 1/(128 • SR)
[ ] . . . . . . . . . . . . . . . . Indicates a specification in an equivalent unit, for example: 0.030 dB [0.35%] or
10.61 Vrms [30.00 Vpp].
≈ . . . . . . . . . . . . . . . . .Indicates an approximate or nominal value, or range of values; not guaranteed.