Charge coupled devices in signal processing. Volume 1: Digital array feasibility

The work reported on here has been exclusively concerned with the digital domain operation of charge coupled devices. One common example of the digital use of charge coupled devices is in the area of memory. But in the present context, we mean a great deal more than just memory. Generally speaking, any digital domain function can be accomplished with charge coupled devices; this means, in particular, digital charge coupled logic (DCCL) functions and digital arithmetic functions. Putting aside for the moment the question of how this is done, let us first ask why this would be done. After all, the charge coupled device technology produces a unique device in that it works as a sampled data analog system. In view of the fact that the CCD is unique in this respect, what are the advantages of using the device in the digital domain. This can be answered by addressing an even more fundamental question; namely, why use any digital device. The reason that people have been using digital devices for some time can be summarized in a few statements: (1) Freedom from parameter variations; (2) Freedom from environment and environment changes; (3) Flexible in application; (4) Easily programmable; (5) Arbitrary accuracy in calculations; (6) Well known characteristics that are easily modeled and simulated; and (7) Low cost due to widespread use.