The 787 CCD Data Compactor is a FASTBUS module designed to process data from the 787 GaAs 500MHz Transient Digitizer module. The Data Compactor accepts sixteen channels of 8-bit digitized data from a CCD module, performs pedestal subtraction and zero-suppression, and formats the data into 32-bit words for readout by FASTBUS.
Data from the CCD Transient Digitizers consists of event pulses and noise superimposed on a fixed background level or pedestal. In order to extract event data from this background, it is necessary to subtract the pedestal from the data, then save event data having a certain minimum amplitude together with fiducial information.