Before you pre process signals you must first define the boreholes that will hold the signal data. A borehole can be any SCPT or downhole measurement at a site. To add a borehole click on the menu Boreholes and select Add borehole command. Alternatively you may click on the 
button located on the Boreholes toolbar. The following dialog will appear:
New borehole dialog
Enter a name description for the borehole inside the Borehole name field and click on the OK button. The new borehole will be added in the Boreholes list and will also be selected.
New borehole added on a project
The toolbar in the Boreholes panel is used for quick access to the commands related to boreholes. These commands may be also accessed form the Boreholes menu at the top of the main application window.
After you have imported the very first borehole, you must define some properties regarding signal manipulation of the borehole. Click on the Borehole properties command under the Boreholes menu item or alternatively you may click on the 
button on the toolbar. The following dialog will appear:
Signal properties for the selected borehole
where:
| • | Signal sampling ratio: This is the sampling ratio the software will you when importing signals. If the portion 1/Sampling ratio is smaller than the recorded step of the signals, SPAS will insert new values based on a simple interpolation formula. For example if the recorder step of the signals is 1 ms and the sampling ratio is 1000 then the signal will imported as it is. If the sampling ratio is 10000 then the signal will be imported with a time step of 0.1 ms. |
| • | Horizontal distance from source: This is the horizontal distance between the hammer point of impact and the borehole. |
| • | Geophone offset: In some SCPTU cases the recorded depth of the signal is actually the depth of the cone tip. Since the geophone is placed on some distance above the cone tip the value entered in this field will be removed from the depth value SPAS will read from the signal file. |
| • | Display FFT frequency: The value entered will be used to set the maximum of the X axes in the frequency domain plot |
If you wish to use these values as the default values for any other borehole that will be added check the Use as default value for new boreholes checkbox. Any changes to the above properties will not affect signals that are already imported to the selected borehole. if you need to apply these changes to your signals you must initiate the Reload signals command.
Before you pre process signals you must first import the signals either by opening a previous project file or by importing signals form ASCII text files. All signals will be imported for the selected borehole (if no borehole is selected the command for importing signals will be disabled). After you imported signals the Field Data page should look like the one shown below:
Main application screen with signal data
Inside the Signals panel there is the list with all imported signals, sorted in ascending order based on their depth value. A check box at the left of every signal will be used by the software to identify if the signal will be included in the calculations (checked) or not (not checked). The toolbar contains access to the most common commands for signal manipulation as shown below:
File manager toolbar
Insert signal from ASCII text file
Delete selected signal form current project
Delete all signals from current project
Define time length for all signals in current project
Define time window for selected signal
Apply basic frequency cutoff filter to selected signal
Preview input data report for selected signals
You may quick access all the available commands for a selected signal from the pop up menu that appears when you right click on it.
Figure 4. Pop up menu
Every time you select a signal from the signals list the two charts at the right will be automatically updated. The first chart from the top presents the actual signal in the time domain and the second chart beneath is the FFT (Fast Fourier Transformation) of that signal. Selecting multiple signals from the list will result multiple line plots on the charts. This way you can check signals from the same depth for repeatability and accordingly check or uncheck signals.
Figure 5. Good signal repeatability
Figure 6. Bad signal repeatabilty (green line)
After you have identified "bad" signals on the charts, left click on them using the mouse and SPAS 2009 will select that signal from the signals list. This way you will know which signal to uncheck.