Browse Prior Art Database

Eliminating Magnetostrictive Ringing in Ferrite Core Memories by Electronic Means

IP.com Disclosure Number: IPCOM000094085D
Original Publication Date: 1966-May-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Collins, TW: AUTHOR [+2]

Abstract

This is a technique by which mechanical oscillations, magnetostrictive ringing, in a three-wire, 3D ferrite core memory due to the drive pulse may be eliminated. The ringing frequency is a function of the core geometry and the material of which it is made and the magnitude of the oscillation is a function of the rise time, fall time, magnitude and duration of the drive pulse. The ringing generates a signal which, if undamped, can continue through the read cycle, thus adversely affecting signal read out.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 76% of the total text.

Page 1 of 2

Eliminating Magnetostrictive Ringing in Ferrite Core Memories by Electronic Means

This is a technique by which mechanical oscillations, magnetostrictive ringing, in a three-wire, 3D ferrite core memory due to the drive pulse may be eliminated. The ringing frequency is a function of the core geometry and the material of which it is made and the magnitude of the oscillation is a function of the rise time, fall time, magnitude and duration of the drive pulse. The ringing generates a signal which, if undamped, can continue through the read cycle, thus adversely affecting signal read out.

Drawing 1 shows waveforms illustrating the above. The rise and fall of current pulses 10 and 12 in adjacent rows of cores initiate two distinct modes of oscillation. Ringing 14, caused by the rise of current 10, is out of phase with ringing 16, caused by the fall of current 10. Similarly for ringing 18 and 20 associated with current 12. If there is any difference in edge slope, duration or magnitude between currents 10 and 12, the resultant ringing 22 and 24, respectively, in general is different in magnitude and phase. Therefore, difference voltage 26 affects the sense amplifier if the oscillations continue into the read cycle.

Drawing 2 shows how equal transient characteristics of currents 10 and 12 are assured. Transformer 30, coupling core rows 32 and 34 to sense amplifier 36, is trifilar wound. Thus its primary windings act as coupling elements which balance any differential tra...