class AliITSFOGeneratorSPD

Author: Henrik Tydesjo

This class is used to generate Fast-OR signals from SPD chips.

This procedure is meant to be used during the digitization,
and will be based on the number of pixels firing in each chip.
The method 'ProcessPixelHit' should be used for each fired
pixel. An efficiency value on Fast-Or signal creation upon a
single fired pixel will then be used. Optionally, there may be
one value per chip or even one value per column. These values
are taken from the class AliITSFOEfficiencySPD, normally placed
in OCDB.

Through a similar class, AliITSFONoiseSPD, there is a
possibility to apply random noise to the generation of fast-or
signals. This will then be performed by method 'ProcessNoise',
normally called after the processing of the fired pixels.

The output signals are represented by the AliITSFOsignalsSPD
class. Basically, it contains a bit map with all the 1200 pixel
chips.