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Spectrogram Plot Options
The spectrogram display options dialog box can be activated by selecting the <Options><Plot Options><Spectrogram> menu or by clicking on the options dialog icon button in the plot toolbar.
Frequency Span: If "Full Span" is selected, the spectrogram will show the entire available frequency range. When "Custom Span" is selected, the frequency values can be directly entered.
Display Update Interval: Normally a new line is added to the spectrogram whenever a new FFT is computed. You may elect to only update the spectrogram every N seconds. This is most useful in the Real-Time mode. In this way, long term frequency -vs- time studies can be conducted.
Colors: There are three choices of palettes. The "Color" palette transitions from black to red, the "Grayscale" palette changes from white to black, and the "Custom" palette lets you choose the minimum and maximum colors.
Scroll Direction: Specifies the direction in which the spectrogram will scroll with increasing time.
Scroll Type: Specifies the type of scrolling. Smooth continuous scrolling scrolls the display with new information added at the edge. Overlapped scrolling does not scroll the display but overlaps when the end of the display is reached.
Plot Top/Range/Bottom: The Plot Top and Range values determine the amplitude (color bar) values. Plot Top is the value at the upper edge of the color bar. The lower edge of the color bar is always equal to the Top value minus the Range value. When linear scaling is selected for the amplitude axis , the Plot Range value is set to zero and cannot be changed. When Log Magnitude scaling is selected for the amplitude axis, the Plot Range value changes to become the Plot Bottom value.
Show Toolbar: Show or hide the plot toolbar. A small + or - button below the toolbar also controls this feature.
Show RPM instead of Time: This will replace the time axis values with RPM values from the tachometer channel. The cursor measurements will also display RPM values.
Show Order instead of Frequency: This will replace the frequency axis values with Order values computed from the tachometer channel. The cursor measurements will also display Order values.
Notes:
Any changes to the display options (with the exception of Direction) will cause the spectrogram to automatically rebuild itself with the new settings (press the Escape key to cancel rebuilding). This behavior will not occur when the analyzer is in the Real-Time mode because the underlying time series data is no longer available.
Copy these settings to other channels: Allows you copy the plot options to other channels you select.
See Also: Spectrogram Plot Order Analysis