Larson Davis SoundExpert LxT, Руководство пользователя

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5-24
View Spectrum Normalized (Optional) LxT Manual
Select the Ref: data field and press
5
to open the
Reference Menu, as shown in FIGURE 5-29.
FIGURE 5-29 Live Reference Menu
The items listed in this menu are as follows:
• 1
• 2
• 3
• 4
• A
• C
• -A
• -C
The first four items permit the user to define four reference
spectra.
The last four items permit the user to use add positive or
negative A or C frequency weightings to the displayed
spectrum.
Setting a Reference Spectrum
By pressing the Set softkey, the current spectrum is set as the
reference spectrum for the selected reference (1, 2, 3 or 4).
Following this procedure, reference spectra 1, 2, 3 and 4 can
be defined. Once defined, the user can choose to display the
live SPL spectrum normalized to any one of these four
reference spectra.
Normalizing using Frequency Weighting
The A and C reference spectrum represent the A and C
frequency ratings sampled at the center frequency of the
selected filter.
Selecting A or C approximates an A or C weighted spectrum
when the original data is unweighted, z weighted. Using -A
and -C removes the effects of A or C frequency weighting.