Electrically reprogrammable transversal filter using charge coupled devices

Claim 1

A CCD digital filter comprising: means for sampling without destroying an analog signal at various points and providing voltages proportional to each sampled signal; means for separately applying said voltages to a CCD analog multiplier; said analog multiplier including means for applying one of said voltages to a sample signal gate which creates charge linearly proportional to the amplitude of said analog signal; means for applying an digital filter coefficient for creating or not-creating said charge depending upon whether the bit of said filter coefficient is 1 or 0; a charge splitting storage gate; means for transferring charge from the substrate beneath the said sampled signal gate to the substrate beneath the said charge splitting gate; a charge splitting control gate for splitting the said charge; means for dumping one portion of the said split charge; and means for passing the said filter coefficient through the said analog multiplier successively according to the number of bits in said filter coefficient which results in the multiplication of said analog signal by said filter coefficient; means for simultaneously dumping the separate multiplied sample signal into a means for summing all sample signals to produce an analog signal modified by digital filter coefficients.