About Sideband Markers

Overview

Setting up sideband markers in Graph View is very similar to setting up harmonic markers, except that sidebands have two frequencies to set: the center frequency and sideband frequency.

Sideband markers place a circle at the center frequency (for example the gear mesh frequency) and an inverted triangle at each of the sidebands (separated equally on either side of the center frequency).

The following is an example of a spectrum with sideband markers. The spectrum has a center frequency of 112.03x (399,760 CPM) and 1X sidebands.

To set sideband markers, use the Sideband Center Frequency () buttons in the graphing toolbar. Alternatively, you can open the graphing Toolbox () and use the Sidebands tab.

Each method is described below.

Toggling Center and Sideband Frequency Sidebands via the Toolbar

Because sidebands require both a center and sideband frequency, there are two toolbar buttons whose state you can toggle.

Sideband Center Frequency

The Sideband Center Frequency button can be toggled between three states:
: Turns it ON and uses a fixed (manually entered) value. This frequency is marked on the graph with a circle. (The value is entered via the Sidebands tab on the Analysis Tools dialog box, as explained below.)
: Turns it OFF.
: Turns ON and uses the tracked cursor value. This allows you to click a peak in a graph and have it marked automatically as the center frequency.

Sideband Frequency

The Sidebands buttons let you specify how the separation of the sidebands from the center frequency will be determined.
: Turns on the sideband markers so they appear as inverted triangles at each of the sidebands (separated equally on either side of the center frequency based on the Sideband separation value entered on the Sidebands tab, shown below).
: Enables track mode so you can click on data in a graph and have its separation from the Center Frequency used as the sideband interval.

Important! The Sidebands toolbar button is only enabled if the Sideband Center Frequency button is toggled on () or set to track mode ().

If the Sideband Center Frequency button is toggled off (), the Sidebands button does not appear on the graphing toolbar.

To specify sidebands from the Toolbox

1. Click the Toolbox button () to open the Analysis Tools dialog box.
2. On the Sidebands tab, select the View sidebands check box to allow center and sideband markers to appear on the graph. (Clearing this check box is the same as turning off sidebands with the Sideband Center Frequency button ().)
3. Decide whether you want the center and sideband frequencies to be set automatically based on where you place the cursor on the graph or whether you want to manually enter a value for these frequencies. (You can use a combination of methods if you choose.)
   1. If you want to set the frequencies based on the cursor click:
      1. Select the Track center option button and then click the peak on the graph you want marked as the center frequency. A circle is placed on the peak.
         
      2. Select the Track sideband option button and click a sideband peak on either side of the marked center frequency. The peak you click is marked as a sideband and inverted triangles will be placed on either side of the center frequency at equal separation.
   2. If you want to set the frequencies manually:
      1. Select the Use manually entered value option button.
         
      2. In the Center frequency box, enter the frequency value you want to be set as the center frequency and select units for it from the drop-down list. If you want to enter the current cursor value, click the Insert cursor value button .
      3. In the Sideband separation box, enter the sideband value you want and select its units from the drop-down list. If you want to use the current cursor's separation from the center frequency as the sideband interval, click the Insert cursor value button.
      4. Click the Update Sideband Cursor to update the graph based on the values and units you specified.
4. Click OK.

Setting Up Sidebands Based on Fault Frequencies

It is common to want sidebands based on the fault frequencies. For example, you may want to use the bearing frequency as the center frequency and have 1X sidebands.

To set a fault frequency as the center frequency, Ctrl+click a fault label to have it marked as the center frequency. If sidebands had previously been set up, the existing sideband frequency will be used. If sidebands had not been set up, then 1X sidebands are marked automatically.

To set a fault frequency as the sideband frequency, Ctrl+Shift+click a fault label to have it marked as the sideband frequency. For example, if the center frequency is set to 3.2X and you Ctrl+Shift+click on the 1X label, sidebands will be marked at 1X intervals (.2X, 1.2X, 2.2X, 3.2X, 4.2X, etc.).