Threshold Logic Circuit
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
The circuit shown in the drawing allows the detection of 5, 7 or 8 bits ON in an 8-bit word to be performed in a minimum of cells and logic layers. Two identical cells 1 and 2 receive four bits of the words and generate at their output the four states: State 1 = 1 out of 4 bits ON State 2 = 2 out of 4 bits ON State 3 = 3 out of 4 bits ON State 4 = 4 bits ON Cell 3 receives the outputs of cells 1 and 2 and generates therefrom three states: State 5 = 5 out of 8 bits ON State 6 = 7 out of 8 bits ON State 7 = 8 bits ON The logic implementation of cells 1 and 2 is based on the following truth table which indicates the number of bits ON among the 16 possible combinations of four bits: Cells 1 and 2 have four outputs X1, X2, X3, X4 and Y1, Y2, Y3, Y4, respectively.