Atec Bruel-Kjaer-2250-2270 - Manual (Page 7)

7
Sound Level Meter Software – BZ-7222
All Type 2250s and Type 2270s come with the Sound Level Meter Software enabled. This makes your
analyzer into a versatile broadband SLM; the software complies with the latest international standard
(IEC 61672–1) as well as previous international and national standards. For a complete list of measured
parameters, see Specifications.
The standard package allows you to document your measurements with written notes and voice
annotations. Notes are added using a virtual keyboard on the touch screen.
Fig. 8
Example of a
typical SLM
display, including
the icons for
added annotations,
visible in the upper
right corner Voice annotations are recorded using a separate commentary
microphone when the commentary pushbutton is pushed and held. Voice
annotations and notes can be attached before, during and after the
measurement. Spoken comments during the measurement should, of
course, be made during a pause or with the microphone placed at a
distance using an extension cable. These unique features allows you to
document your measurement (where, when, how, etc.) and always have
this information attached to the measurement. Notes and voice
annotations can be reviewed on the instrument itself or after the data has
been transferred to a PC.
If Signal Recording Option BZ-7226 (see page 10) is also enabled, you
can record all or part of the measured signal. This recording is safely
stored with the measurement. Thus it is easy to document that measured
levels are indeed related to a particular noise source under investigation.
Frequency Analysis Software – BZ-7223
Fig. 9
Frequency Analysis
Software BZ-7223
displays (left to right):
1/3-octave showing
dual spectra and
generator icon, Cursor
readouts, Loudness
and Noise Rating (NR)
results
The decisive band and
the corresponding NR
curve is shown
Frequency Analysis Software BZ-7223
is an optional application. It allows you
to make real-time measurements in
1/1- and 1/3-octave bands over a wide
frequency range. This makes it a
simple matter to obtain spectra in order
to, for example, select hearing
protection, qualify heat and ventilation
systems, and assess tonality.
Each band has a full and unrivalled
dynamic range from the noise floor in
that particular band to 140 dB: a
dynamic range generally in excess
of 135 dB.
The available frequency ranges are centre frequencies 8 Hz to 16 kHz (for 1/1-octave spectra) and centre
frequencies 6.3 Hz to 20 kHz (1/3-octave spectra).
Spectra can be A-, B-, C- or Z-weighted. Five spectra and full spectral statistics are measured and stored. In
addition, seven different L
N
spectra and instantaneous values are available for display. Two spectra (for
example, a minimum and maximum spectrum) can be superimposed on the display. All the broadband
quantities measured by Sound Level Meter Software BZ-7222 are computed in parallel with the frequency
analysis. Spectral analyses can be documented using notes and voice annotations.
For a measured spectrum, single-number parameters, such as Noise Rating, Speech Interference Level and
Loudness, can be calculated and displayed for noise impact analysis and limit comparison. A programmable
generator is available for measurements requiring a sound source. You can select white or pink noise and
set the upper and lower frequency limits.