CROSSTALK ON DIGIT LINES IN A PLATED-WIRE MEMORY STACK USING A FERRITE KEEPER.

There are few papers or reports dealing with the subject of crosstalk in memory stacks using ferrite keepers both above and below the magnetic lines. This report begins with a general analysis using magnetic circuits to define the crosstalk due to magnetic coupling between digit lines constructed in the manner described above. New design relationships are then presented taking into account crosstalk effects. The results of the analysis are used to develop memory stack designs to reduce crosstalk and to show the relationship between digit line transposition and near-end crosstalk and far-end crosstalk. A memory stack using this type of construction is seen to act like a transformer with respect to common mode signals and it is shown that this is the cause of extremely large crosstalk. The authors give a method of digit line transposition in one plane at a time which provides one-half the crosstalk that occurs in transposition in two planes at once. Experimental results with a 2K-word multiplied by 72-bit memory stack are found to correspond very closely with the theoretical results.