LeCroy has recently added the ability to recall waveforms stored in a specific ASCII format to be recalled into the scope. The new feature allows waveforms stored in Excel format using the header sub-format to be saved and recalled to the scope. This capability allows users to save the easily readable text format while not giving up the ability to return the waveform trace to the scope for additional measurements.
Waveform storage is controlled from the ‘Save Waveform’ dialog box. The Save Waveform dialog box can be reached from the File pulldown menu. Figure 1 shows the oscilloscope setup to store an ASCII waveform using the Excel format. Note that the subformat selection is set to save with header. The Excel compatible format is a comma delimited ASCII text format, sometimes referred to as a .csv file format. The dialog box also allows the user to select where the file will be stored.
The data stored in this format includes a header, shown in columns A-C of the excel spreadsheet shown in Figure 2. The time data is stored in column D while amplitude data is written to column E. The header includes five items. The record length contains the number of samples in the waveform. The sample interval is the period of the sampling clock. The trigger point indicates the location of the trigger point within the waveform. In this case it is near the center of the waveform. The trigger time is the fractional part of the real time clock timestamp. The horizontal offset is the time between the trigger and the first point in the waveform.
Recalling the waveform is accomplished using the ‘Recall Waveform‘ dialog box. This is also accessible under the ‘File’ pulldown menu.
Figure 3 shows the Recall Waveform dialog box. Recalled waveforms are displayed in one of the scope four internal memories designated M1 through M4. In the setup shown, the waveform, from trace 2, ‘C2Trace00000.csv’ was recalled into memory M1 when the Recall Now! Button was pushed.
The selection of the waveform to .csv file be recalled is controlled from the Next ‘File will be recalled from’ field in the dialog box. The file name can be enter explicitly or you can choose to browse. If you do use the browse feature make sure to set the ‘File of type’ field to “.” To see all waveform files. The default file type is the binary .trc trace file.
The ability to recall selected ASCII files adds additional flexibility to the use of LeCroy oscilloscopes allowing users to both read the data values as well as being able to do post-processing on ASCII data.