# Camera trigger logic - DigitalSum

The simulation of the trigger logic for the digital sum trigger is
defined as follows:

1.  An (optional) shaping of the input signal is applied using a shaper
    signal defined in .

2.  An (optional) time offset in FADC bins, (), used in the convoluted
    signal of the "discriminator input" signal $\times$ the (effectively
    a convolution kernel).

3.  If necessary, the digital signal in each pixel can be clipped either
    before or after shaping. The clipping thresholds are defined
    respectively by and ).

4.  The digital trigger logic, defined in the , is then applied and can
    be either of the following options:

    1.  The digital signals in trigger clusters of adjacent pixel
        patches are summed and the trigger fires if the sum over all
        pixels in a cluster is higher than a predefined value, . A patch
        is composed of three adjacent pixels and a trigger cluster
        consists of three patches, nine pixels in total. One patch can
        be part of a few trigger clusters, such that the clusters
        overlap. An example for this case for the definition in the is
        "DigitalSumTrigger \* of 1719\[1724,1726\] 1716\[1717,1718\]
        1732\[1733,1734\].\"

    2.  SmartPixel logic: e.g. a pixel cluster of seven pixel clusters
        where the central pixel must have fired (would be a line in the
        like "Trigger \* of 561 562 597 +598 599 633 634", with the
        smart pixel indicated by the '+').