Inherent error correction in analogue CCD adaptive filters

There are many sources of imperfection in an analogue charge-coupled device CCD programmable transversal filter (PTF) which cause problems; namely, varying signal and reference channel gains, charge-transfer inefficiency in the CCD and multiplier errors. This paper shows how these error sources may be automatically compensated for in an adaptive filter based on a CCD programmable filter. The adaptive filter is based on a form of the Widrow LMS algorithm, which is both simple and well suited to microprocessor implementation, particularly where that is the means of implementing the PTF reference waveform.