Abstract: D.C. reconstruction of sampled CCD output signals is achieved by subtracting the output current pulses of two CCDs (or subtracting parallel outputs of the same CCD) with a differencing circuit containing two biasing current mirrors, a current sink device and an output capacitor. The two current mirrors are used with each biasing the output of a complementary CCD to positive and acting to mirror the CCD output current. A third current mirror converts the output of one of the CCDs into a current sink. An output capacitor performs subtracting by converting all outputs to voltage and combining the positive biased output of one CCD with the current said output of the second CCD.