Analog transversal filtering and correlation with progressive summation of analog signals

摘要

"Progressive summation" of analog signals with a parallel-in/serial-out (P/I/SO) CCD structure replaces the conventional "simultaneous summation" of analog signals in serial-in/parallel-out (SI/PO) structured systems. Gain non-uniformities presented by buffer circuits and caused in part by threshold non-uniformities are avoided; on-chip power consumption is reduced, thereby avoiding a source of further exaggeration of gain non-uniformities of buffer circuits. Transversal filtering and correlation systems in accordance with the invention accordingly are achieved with these problems of prior art circuits avoided. Reduced power consumption on-chip also maintains more reasonable and constant operating temperature levels, avoiding deleterious effects of temperature increases on dynamic range of CCD systems due to leakage current levels which sharply increase with increased temperature, contributing noise and reducing the maximum charge potential of the CCD wells available for signal.