SYSTEMES LOGIQUES UTILISABLES NOTAMMENT DANS DES DISPOSITIFS DE RECONNAISSANCE DE CARACTERES

1476880 Character recognition programmable logic circuit INTERNATIONAL BUSINESS MACHINES CORP 17 April 1975 [24 June 1974 (2)] 15770/75 Heading G4R A logic circuit arrangement for use in a character recognition device has a shift register SR1- 48 feeding a plurality of programmable logic circuits P AND 1-48. Data representing for instance a scanning matric 40 Î 24 is fed serially to a 960 bit shift register formed of 48 20 bit sections. Each section feeds a plurality of programmable AND circuits 1-48 each of which produces a one bit output which is fed back to 64 feedback latches which also feed the P AND circuits. Selected P AND circuits 37-48 also feed output latches. The P AND circuits may be as shown in Fig. 8C for a three input gate in which latches 115, 116, 124, 125, 133, 134 are set to determine the logic operation. If both latches for an input are zero the inverters, e.g. 119, 120 for input A feed "1"s to AND gate 123. If only one is zero then either A or A is fed to gate 123. OR functions are produced using inverters and de Morgan's theorem A - B = A + B. The shift register may contain dummy registers which are not connected to the logic circuits to reduce the number of connections required while still storing the same number of bits. Thus portions of an area are processed alternately (Fig. 14, not shown).