Index: fact/tools/pyscripts/pyfact/fir_filter.py
===================================================================
--- fact/tools/pyscripts/pyfact/fir_filter.py	(revision 13326)
+++ fact/tools/pyscripts/pyfact/fir_filter.py	(revision 13327)
@@ -14,6 +14,11 @@
     
     def __init__(self, b, a, name = 'general FIR filter'):
-        """ initialize filter coefficients
-        
+        """
+            See `scipy.signal.lfilter() <http://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.lfilter.html#scipy.signal.lfilter>`_
+                *b* The numerator coefficient vector (1D)
+                
+                *a* The denominator coefficient vector (1D). 
+                
+                If a[0] is not 1, then both a and b are normalized by a[0].
         """
         self.a = a
@@ -22,4 +27,8 @@
         
     def __call__(self, data):
+        """ Apply generic FIR filter to *data* using scipy.signal.lfilter()
+            
+            *data* 1D or 2D numpy array
+        """
         length = max(len(self.a),len(self.b))-1
         if length > 0: