a charge - transfer - device transversal filter which makes use of tap - weight - adjustment circuitry for removing effects of charge - transfer inefficiency and fixed - pattern noise . the tap weights are adjusted by measuring the response of the ctd - transversal filter to an isolated pulse input and to a zero - frequency input . the results of the measurements and reference - filter coefficients are used by the tap - weight - adjustment circuitry in order to set tap weights for the ctd - transversal filter . the tap - weight - adjustment circuitry allows the frequency response of the ctd transversal filter to be accurately tailored even though the ctd filter suffers imperfections due to cti and fpn .