Norsonic nor140, Instructional Manual, Page: 112 / 220

94
Chapter 19
Reference Spectrum
Reference Spectrum
General
The Reference Spectra feature is used for compari-
son of any measured frequency spectrum with a pre-
selected user defined spectrum. It functions both on
1/1-octave and 1/3-octave spectra.
The measured spectrum may be compared to an
upper limit, a lower limit, or both an upper and a lower
based on user defined boundary spectra. If the meas-
ured spectrum exceeds the boundaries, a “NoGo”
warning may be given.
The Reference Spectra features will be available
when option 2 is installed. This option requires that
option 1 (1/1-octave filters) is present.
Activating the Reference
Spectrum features
The Reference Spectrum features are controlled from
the sub menu 1 in the Frequency mode menu. The ba-
sic requirement is that the Freq. Mode is turned On in
the upper part of the menu.
In the Ref. curve menu, either the Upper or the Low-
er, or both, must be turned On. These selection will turn
on the currently stored upper and/or lower Reference
Spectra in the graphical level vs. frequency display.
This menu is opened by first moving the field cur-
sor into the lower part of the Freq. Mode menu, and
then using the
1
key to open the Reference parameter
menu.
The upper and/or lower spectra are displayed using
short lines for each individual frequency band. The lines
are of XOR type which means the lines will always be
visible both with and without the actual overlayed bar-
graph. See the figures on next page which shows exam-
ples with only the upper 1/1-octave and with both upper
and lower 1/3-octave Reference Spectra activated.
Selecting the Reference Spectra
Selection and/or editing of the individual Reference
Spectra are done in the Ref.curve menu.
Frequency mode menu