added alpha to alpha_SPEC format function in case non SPEC format alpha is read from file

9a06dddb · Peter Jansweijer · b8416829 · 9a06dddb
Commit 9a06dddb authored Apr 05, 2018 by Peter Jansweijer
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Showing with 21 additions and 2 deletions

pps_diff.py sw/insitu_alpha/pps_diff.py +21 -2

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--- a/sw/insitu_alpha/pps_diff.py
+++ b/sw/insitu_alpha/pps_diff.py
@@ -303,6 +303,23 @@ def delta_delay(scope, num_avg = 1):

  return

+############################################################################
+def spec_alpha(alpha):
+  """
+  returns the value of alpha as it is used by the SPEC
+  (see also White Rabbit Calibration procudeure:
+  http://www.ohwr.org/attachments/4092/WR_Calibration-v1.1-20151109.pdf
+  equation 11.
+
+  alpha         -- <float> alpha value
+
+  returns:
+  alpha         -- <float> alpha according to SPEC 
+
+  """
+  return(2**40 * (((alpha+1)/(alpha+2))-0.5))
+
+
 ############################################################################
 def file_to_array(filename):
  """
@@ -315,7 +332,7 @@ def file_to_array(filename):
              [itu-ch, SPEC_alpha_3wl],
                   :
           False
-              "Not a Delat Delay file"
+              "Not a Delta Delay file"
  """

  # create empty list
@@ -338,7 +355,9 @@ def file_to_array(filename):

      # Values of interest on one line are:
      #   # lambda-1[nm], ITU-ch, SPEC_alpha_3wl(lambda-1)
-      pair = float(line_lst[1]),float(line_lst[2])
+      # pair = float(line_lst[1]),float(line_lst[2])
+      #   # lambda-1[nm], ITU-ch, alpha_sel(lambda-1)
+      pair = float(line_lst[1]),int(round(spec_alpha(float(line_lst[2]))))
      pairs.append(pair)

  arr_pair=numpy.array(pairs)