Browse Prior Art Database

Double Read Magnetic Film Memory

IP.com Disclosure Number: IPCOM000075746D
Original Publication Date: 1971-Nov-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Paton, A: AUTHOR [+2]

Abstract

In a memory having a magnetic film 10, noise due to skew and capacitive coupling is substantially eliminated during read operation by driving each selected element, e.g., 12, of the memory film with two consecutive read bursts, of equal length but of opposite polarity or phase.

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 87% of the total text.

Page 1 of 2

Double Read Magnetic Film Memory

In a memory having a magnetic film 10, noise due to skew and capacitive coupling is substantially eliminated during read operation by driving each selected element, e.g., 12, of the memory film with two consecutive read bursts, of equal length but of opposite polarity or phase.

A first burst 14 of the two bursts is applied from word driver 16 to word line 18 to produce in sense line 20 a first signal, and a second burst 22 of the two bursts is then immediately applied from word driver 16 to word line 18 to produce in sense line 20 a second signal.

Assuming small angle switching, the instantaneous first signal during the first burst 14 is Vs1 = K d over dt(hd) +/- 0o hd d over dt(hd), where hd is the relative drive field at element 12 which is equal to Hd/Hk, wherein Hd is the actual word field in oersteds and Hk is the anisotropy field of film 10, 0o is the maximum available flux from element 12, and K is a constant including capacitive coupling from word to bit lines 18, 20 and also the skew of the film easy axis.

The instantaneous second signal during the second burst 22 is Vs2 = - K d over dt(hd) +/- 0o hd d over dt(hd).

Each of these signals is multiplied in multiplier 24 by reference voltage, Vref, from reference voltage source 26, proportional to d over dt (hd), and then integrating in integrator 28 before applying the resulting signals to sense amplifier 30, that is,

(Image Omitted)

The omega term survives the integration a...