BRUEL & KJAER 2203 - Page 10

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Free-field sound pressure level measurement accuracy of± 1 dB.
Essentially omnidirectional microphone characteristics (see
Section 5.1 ). Square law type measurement indication.
Tolerances on meter scale calibration and range shift error are
specified.
A "Fast" meter dynamic characteristic: Response to a 200 millisec-
ond pulse must be within -2 and 0 dB of the indication for a con-
tinuous signal of same frequency and amplitude. Damping such that
overswing on a suddenly applied steady signal is between + 0,1 and
+ 1,1 dB.
An alternative "Slow" meter characteristic (optional): Response to a
500 millisecond pulse must be within -5 and -3 dB of the indica-
tion for a continuous signal of same frequency and amplitude.
Damping such that overswing on a suddenly applied steady signal is
between + 0,1 and + 1, 6 dB compared to final steady indication
(which must be within 0,1 dB of level indicated with "Fast" charac-
teristic).
Specifications are also given for frequency range capabilities, and
maximum permissible sensitivity to external and environmental in-
fluences.
The IEC publication specifically states that the Precision Sound
Level Meter is designed to give objective measurements which un-
der certain conditions approximate the subjective impression of
soL.nd . The 2203 meets all applicable IEC criteria and can be used
for "1.' 1e measurement of most continuous sounds.
Full d: scussion of sound and vibration measurement techniques is
given in two Bruel & Kjcer books; "Acoustic Noise Measurements"
and "Mechanical Vibration and Shock Measurements" which are
available on request.