Browse Prior Art Database

Automatic Shmoo Plotter

IP.com Disclosure Number: IPCOM000092594D
Original Publication Date: 1966-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Gersbach, JE: AUTHOR

Abstract

Continuous line 10 defining the boundary of various combinations of word and bit drive currents that provide satisfactory operation of memory 12 can be plotted on X-Y plotter 14. Such is effected by changing the direction of change of the excitation supplied to the power supplies 16 and 18 of the memory each time an error condition occurs and ends.

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Automatic Shmoo Plotter

Continuous line 10 defining the boundary of various combinations of word and bit drive currents that provide satisfactory operation of memory 12 can be plotted on X-Y plotter 14. Such is effected by changing the direction of change of the excitation supplied to the power supplies 16 and 18 of the memory each time an error condition occurs and ends.

Initially the magnitude of the excitation to both power supplies 16 and 18 is continuously increased by X and Y ramp generators 20 and 22 respectively. This causes the power supply voltages to both increase from their manual levels represented by point A until an error condition is detected by memory tester 24 at point B.

Tester 24 then signals generator 22 through ramp control 26 to decrease the excitation to the Z power supply. With this the plotted line moves from point B toward point C. At the latter point, the error condition is alleviated and the voltage supplied by generator 22 starts increasing again until a second error condition is detected at point D. The voltage supplied by generator 22 is again reversed.

Continued reversal of the Y voltage in the above manner causes the plot to follow the error boundary until it reaches point E. At the latter point, decreasing the Y voltage does not alleviate the error condition. Therefore, after a period of time of a continued error condition. Ramp control 26 reverses the excitation supplied by generator 20 to supply 16. Now an error condition is d...