Linear charge-coupled device signal-processing techniques

New methods for linear launching, weighting, and nondestructive charge sensing in charge-coupled devices (CCD's) are described. These methods employ electronic circuitry at the input and output nodes of the CCD, which linearize the signals, eliminate the nonlinear effect of depletion region capacitance and are also independent of device parameter variations such as electrode area, and absolute values of threshold voltage and oxide thickness. Results indicate a maximum nonlinear distortion of 2.4 percent which is equivalent to a second harmonic distortion level of -38 dB if all distortion present is assumed to be due to second harmonic distortion. Significantly better results are believed possible with circuit optimization. These methods are directly applicable to many CCD signal processing systems and are particularly aimed at CCD transversal filters.