TM 1-6625-724-13&P
0010 00
0010 00-7
g.
Using Spectral Displays
There are three basic types of spectral displays available on the AVA. These are:
1. 400 Point Power Spectrum. The 400-point power spectrum displays vibration amplitude for the
asynchronous or synchronous power spectrum modes, see figure 3. All 400 points are displayed on a
single screen. The cursor is controlled by the LEFT and RIGHT arrow keys on the keypad. The amplitude
and frequency at the cursor position are displayed in the upper right hand corner of the screen. Function
key F1 allows the cursor to be toggled between one normal (NORMAL) cursor and harmonic (HARMON)
cursors. Function key F2 selects a data table format where lines of peak-peak data are sorted by amplitude
in descending order and function key F3 selects a data table format where lines of peak-peak data are
sorted by frequency in increasing order, see figure 3. Function key F4 displays a menu that allows
selection of the number of values (5,10, 20, or 400) to be displayed in tables selected by function keys F2
and F3.
Figure 3. 400 Point Power Spectrum Display
2. 128 Point Synchronous Spectrum Display. The synchronous power spectrum display, see figure 4, allows
the display of 128 points of vibration data collected with the synchronous sampled time averaged mode.
This display provides up to the 32nd harmonic vibration point with a resolution of 1/4 harmonic. The cursor
is controlled by the LEFT and RIGHT arrow keys on the keypad. The amplitude, phase, and frequency of
the data point at the cursor is displayed in the right side of the screen. Function key F1 allows a harmonic
cursor to be displayed on the screen. Function key F2 allows the frequency axis units to be toggled
between orders and frequency. Function key F3 selects a data table format as shown in the figure 4. Any
of the selected screens can be printed by pressing the PRINT key.
Figure 4. 128 Point Synchronous Power Spectrum Display
3. 6400 Point Zoom Display. The 6400-point Zoom display, figure 5, provides 6400 points of spectral data
taken in the zoom measurement mode. This display type is applicable to the asynchronous or synchronous
F1
F2
F3
F4
FLOWN 15:41:00 N 01 AUG 01
FLOWN 15:41:00 N 01 AUG 01
CURSOR 0.00ips 126.2 Hz
