When signals are not clear enough, the cross correlation function between 2 signals may not work properly. In such cases a good practice is to limit the execution using a window area. Signal values that fall into this window are preserved where all other data values are set to zero (0.00). In this way the execution of the cross correlation function is limited inside the window time length.
Calling the time window command
Calling the time window command after a signal is selected pos up the dialog shown in the following Figure.
Signal window dialog
The dialog provides a track bar with two button, located on the top. Moving the left button to the right is used to define the start position of the time window. Moving the right button to the left is used to define the end position of the time window. SPAS 2009 will provide a visual inspection for the time window by drawing a gray background area for data that lay outside the time window, as shown in figure 18.
Visual inspection of the time window
Applying the define time window to all signals of the same depth is done by checking the Apply to all signals at same depth check box prior to clicking the OK button. Resetting the time window is done by clicking on the Reset window button.
SPAS 2009 will draw the areas outside the time window with a gray color as shown below:
A signal with an active time window