PL-D720 Readout Timing

The PL-D720 series are global shutter cameras that allow overlapped exposure of one frame while reading out another.  Thus, the maximum frame rate is determined by the greater of the exposure time or readout time, plus some frame overhead time. Readout of frame N must be complete just before exposure of frame N+1 is complete, at which point frame N+1 is “transferred” to the readout nodes in the sensor.  This transfer is known as the Frame Overhead Time (FOT).

The maxFrameRate can be calculated as follows:

 maxFrameRate = 1/minFrameTime

 minFrameTime = FOT + MAX(readoutTime, exposureTime + minResetTime)

The readoutTime of the PL-D720 series can be calculated as follows:

 readOutTime = rowTime * (height + 8)/decimation + blackRowTime

 Where:

    rowTime = ((width + 8)/decimation) * clkPeriod / numLVDStaps + rowOverheadTime

    blackRowTime = ((maxWidth + 8)/decimation) * clkPeriod / numLVDStaps + rowOverheadTime

    Where:

       (8 is the number of extra rows/columns that are used during the readout timing of the sensor)

       Width = the ROI Width chosen

       maxWidth = the maximum width of the sensor (PL-D721: 1280, PL-D722: 2048, PL-D725: 2592)

       decimation = the amount of DECIMATION being applied at the sensor (default is 1 for no decimation)

       numLVDStaps = PL-D721: 4 
                     PL-D722 : 4 
                     PL-D725 : 8

       clkPeriod = 1 / 62 MHz

       rowOverheadTime = PL-D721:  70 * clkPeriod, 
                         PL-D722/725: 104 * clkPeriod

 The minResetTime is (2 * rowTime)