Detailed docstring in sortBAMdata()

bunch_pattern.py

@@ -183,7 +183,11 @@ def repRate(data, sase='sase3'):
 
 def sortBAMdata(data, key='sase3'):
     ''' Extracts beam arrival monitor data from the raw arrays 'BAM6', 'BAM7', etc...
-        according to the bunchPatternTable.
+        according to the bunchPatternTable. The BAM arrays contain 7220 values, which
+        corresponds to FLASH busrt length of 800 us @ 9 MHz. The bunchPatternTable
+        only has 2700 values, corresponding to XFEL 600 us burst length @ 4.5 MHz.
+        Hence, we truncate the BAM arrays to 5400 with a stride of 2 and match them
+        to the bunchPatternTable.
         Inputs:
             data: xarray Dataset containing BAM arrays
             key: str, ['sase1', 'sase2', 'sase3', 'scs_ppl']