Cirrus Research CR 151, Руководство пользователя

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optimus sound level meter user manual
Page 24
Leq View
Shows you the Leq, Peak, LAE (SEL) and C-A values with a choice of A, C and Z
frequency weightings.
The C-A data can be used with the HML method for selecting hearing protection.
If the Time Weighting is set to Impulse, the C-A function is replaced by LAeq,I (also
known as LAIeq).
When the instrument is set to the German language, an additional ‘Taktmaximal’ page
is also available.
1:1 Octave Band View
This view shows the noise levels divided into Octave frequency bands. This can be
used to aid in the selection of hearing protection and also for noise control
applications.
Some models also have the capability to show NR & NC Curves and resultant values.
1:3 Octave Band View
This view shows the noise levels divided into 1:3 Octave (called ‘third-octave’)
frequency bands. This can be used for environmental noise measurements and also
for noise control applications.
The 1:3 Octave Band View also provides Leq LF (20Hz-200Hz) and LAeq LF (20Hz-
200Hz).
Tone detection
This is a capability on some instruments, displayed within the 1:3 octave view.
Instruments with Tone Detection use either the ISO 1996-2:2007 Simplified Method or
an improved method developed by Cirrus Research which is based upon the ISO
standard, extended to include tones between bands, tones in outer bands and Z-
weighting. The ISO method only applies to overall data when measuring or reviewing,
whereas the Cirrus Improved Method also applies to instantaneous live values.
When a tone is detected, the band is highlighted in blue on both the graphical and
numerical pages.
This can be set to the Cirrus Improved Method (default setting) or the ISO 1996
method in NoiseTools.