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Hand-held Analyzer Types 2250 and 2270 – User Manual
8) To exit the Spectrum Table, tap the icon.
9) Auto Zoom and Auto Scale automatically close the drop-down menu, otherwise, select
Close, tap outside the drop-down list or use the Left arrow pushbutton to close the
menu.
Hint: A quick way of auto zooming is to tap anywhere in the spectrum and then press the
Accept pushbutton twice.
Note: Save the template, if you want to use the display settings for other measurements.
Some parameters are calculated based on the spectra:
• SIL, PSIL, SIL3 and L
Xeq
(f1–f2) are calculated during the measurement and saved
together with the other measurement data
• The Noise Parameters NC, NR, RC, NCB, Loudness and Loudness Level are for display
only and calculated based on measured L
Xeq
spectra. This means that whenever you have a
L
Xeq
spectrum you can also calculate and display these parameters
• NC, NR, RC and NCB are defined for 1/1-octave L
Zeq
spectra, however, NC, NR, RC and
NCB are calculated for any frequency weighting and any octave bandwidth. A-, B- and
C-weighted spectra are converted to Z-weighted spectra and 1/3-octave spectra are
converted to 1/1-octave spectra before the calculation
• Loudness and Loudness Level are calculated for 1/3-octave spectra with any frequency
weighting. A, B and C weighted spectra are converted to Z-weighted spectra before the
calculation
If 1/1-octave L
Zeq
spectra have been measured, then you can display a Noise Curve together
with the L
Zeq
spectrum, see example in Fig.10.6.
Fig.10.6
Displaying a Noise Curve
together with the L
Zeq
spectrum
For RC and NCB you also have the possibility of displaying the limit curves for Rumble and
Hiss, and for Rattle and Vibration together with the 1/1-octave L
Zeq
spectrum.
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