Next: B Skirt and MPW
Up: iii Operation
Previous: iii Operation
The base output from the CCD module with no input signal is composed of three parts; a DC offset, a gradual slope due to leakage current in the CCD, and a random patterning due to material and processing variations. A Pedestal FIFO is provided on the compactor daughterboard which may be loaded with a unique pedestal value for each bin. This pedestal data may be obtained by averaging several data sets taken with no input signal.
Figure 4 shows a typical scintillator pulse after digitization. The top plot shows a portion of the raw digital data from the CCD board. The second shows the corresponding CCD pedestal data, and the bottom plot shows the resulting corrected data. The output data is not allowed to go negative for input data that is below pedestal.
Next: B Skirt and MPW
Up: iii Operation
Previous: iii Operation