Hitachi, Ltd.

Nippon Telegraph and Telephone Public Corporation

Shoji Yoshimoto

Ryuji Yano

Kazuhiro Ishida

Toshio Futami

Shigeru Yoshizawa

Kazutoshi Yoshida

Akira Kobayashi

Shinsaku Chiba

Nakahiko Yamaguchi

Tadaaki Etoh

Susumu Hibi

In a cassette type magnetic bubble memory device comprising: a magnetic bubble memory device mounted to a base plate and having a magnetic bubble memory element, a pair of coils for generation of a rotating field for driving the element, and a pair of permanent magnet plates and yoke plates for applying a bias field to the element; and an electric signal connector section provided on one end of the base plate and adapted to be connected to a loader, an electrically conductive metal frame is provided which surrounds at least the connector section, and a resin sealing medium is provided which seals at least the magnetic bubble memory device continuously to the inner walls of said frame.

Cassette type magnetic bubble memory device

In a detector of an magnetic bubble memory device of the type comprising a magnetic bubble memory element having a detector, a source of constant current for passing constant current through the detector for producing a bubble output signal according to the magnetoresistive effect of a detector, a preamplifier for amplifying the output signal, a DC regenerator for regenerating an output signal of the preamplifier and a discriminator for converting the DC regenerated signal into a binary code, there is provided a holding circuit connected between the DC regenerator and the discriminator for holding a peak value of the DC regenerated signal for a predetermined time.

Output signal detectors of magnetic bubble memory devices

In a magnetic bubble memory apparatus of cassette type comprising a magnetic bubble memory device and a signal detector contained in a cassette, the memory device and the signal detector are surrounded by a grounded shield made of electroconductive material.

Magnetic bubble memory apparatus

Method and apparatus for testing a magnetic bubble memory are disclosed wherein a most severe magnetic bubble domain arrangement which fully causes the ununiformity of magnetic interaction between magnetic bubble domains is experimentally determined, and a basic pattern [P] and a test information pattern determining an arrangement of the basic patterns [P] and complementary patterns [P] thereof for realizing that magnetic bubble domain arrangement are stored in memory units, respectively, and the basic patterns [P] and the complementary patterns [P] are sequentially read out in accordance with the test information pattern to generate magnetic bubble domain trains in a storage area of the magnetic bubble memory. The magnetic bubble domain trains are then read out by a magnetic bubble detector and the read-out signals are converted to logical signals by a sense amplifier unit and the logical signals are synchronized with logical signals corresponding to the test information pattern and compared therewith to produce an identity or non-identity signal and thus the disclosed method and apparatus for testing the magnetic bubble memory can exactly evaluate a memory characteristic of the magnetic bubble memory.

Method and apparatus for testing a magnetic bubble memory

Growing community of inventors

Mobara, Japan

Shoji Yoshimoto