R69-20 An Analog Card Capacity Correlator as Applied to OCR
Vernon L. Larrowe · IEEE Transactions on Computers · 1969
This paper describes a special analog correlator which is used for optical character recognition (OCR). The correlator is built around a special" card capacity read only storage (CCROS)" memory. Each bit in this CCROS memory is represented by a 1-pF capacitor, which may be removed from the circuit by appropriately punching a special Hollerith card on which is printed one plate of the capacitor. The other plate of the capacitor is printed on a printed circuit board pressed against the reverse side of the card, and the portion of the card between the two plates forms the capacitor's dielectric.