Electrical computers and digital processing systems: memory – Storage accessing and control – Specific memory composition
Reexamination Certificate
1998-09-11
2001-01-09
Cabeca, John W. (Department: 2752)
Electrical computers and digital processing systems: memory
Storage accessing and control
Specific memory composition
C360S055000, C360S065000, C360S066000, C711S112000, C711S002000, C710S013000, C710S065000
Reexamination Certificate
active
06173363
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data transmission device and, more particularly, to a data transmission device which can be attached to a magnetic recording and reproducing apparatus performing a data recording or reproducing operation on a recording medium by using a magnetic recording and reproducing head, a memory medium being accommodated in the data transmission device so that a recording or reproducing operation on the memory medium is performed via the magnetic recording and reproducing apparatus, the memory medium having memory elements for storing information therein.
2. Description of the Related Art
A memory card is popular as a memory mainly for portable computers such as a notebook-type PC (personal computer). In association with downsizing of PCs and popularization of digital cameras, a small memory card has become popular in the market.
There are several types of small memory cards such as a miniature card type or a smart media type, and small memory cards having a memory capacity of 2 MB to 8 MB have come into a wide use in the market. Recently, an IC card having a memory capacity for storing a relatively small amount of data such as individual information or identification information (ID) has become popular.
However, in order to store information in such a small-type memory card or an IC card, a recording and reproducing apparatus exclusive for each medium is required. Accordingly, such an exclusive recording and reproducing apparatus must be connected to a conventional personal computer when the memory card is used with the conventional personal computer. Additionally, a space must be reserved inside the personal computer when the exclusive recording and reproducing apparatus is incorporated into the personal computer.
This is contrary to a trend of downsizing of the personal computer. Accordingly, it is suggested that a method for using a floppy disc drive as a recording and reproducing apparatus be used for recording or reproducing the IC card since the floppy disc drive is popular in the personal computer market and is incorporated in most personal computers as a data storing medium.
The basic concept of such a technology to permit usage of the small-type memory card or the IC card by the floppy disc drive is that no change should be made to the conventional floppy disc drive. That is, considering the popularization of the floppy disc drive on the market, the use of the conventional floppy disc drive has an advantage. Accordingly, a method has been developed in which the small-type memory card or the IC card is attached to an adapter having an outside configuration similar to the floppy disc cartridge so that the adapter is attached to the floppy disc drive, and, thereby, the memory card or the IC card is magnetically connected to the floppy disc drive via a magnetic head of the floppy disc drive so as to exchange signals therebetween.
FIG. 1
is a block diagram of a conventional floppy disc drive.
A floppy disc
2
is inserted into the floppy disc drive
1
. A slide shutter
4
of the floppy disc
2
is opened by a loading mechanism
3
during an insertion of the floppy disc
2
, and, thereby, a magnetic head
6
contacts a disc
5
accommodated in the floppy disc
2
.
When the floppy disc
2
is loaded at a predetermined loading position inside the floppy disc drive
1
, a spindle motor
7
is engaged with the disc
5
. The disc
5
is rotated by the spindle motor
7
in a direction indicated by an arrow A at a predetermined speed, and the magnetic head
6
slides on the disc
5
so that data is recorded by magnetizing the disc
5
by the magnetic head
6
.
The magnetic head
6
is mounted on an actuator
8
, and is moved in a radial direction (direction of an arrow B) of the disc
5
. Data is recorded on the disc
5
by moving the magnetic head
6
in a radial direction (direction of the arrow B) by operating the actuator
8
.
The spindle motor
7
is connected to a motor control circuit
9
so as to be rotated at a constant rotational speed. The motor control circuit
9
is connected to a control circuit
10
so as to control an operation of the spindle motor
7
in response to a motor control signal provided from the control circuit
10
.
The actuator
8
is connected to the control circuit
10
. The actuator
8
moves the magnetic head
6
in a radial direction (direction of the arrow B) of the disc
5
in response to a tracking position control signal so as to select a tracking position.
Additionally, the magnetic head
6
is connected to a read/write circuit
11
so as to record data on the disc
5
by a recording signal provided from the read/write circuit
11
. The magnetic head
6
also detects information recorded on the disc
5
by converting changes in magnetization of the disc
5
into a current. The read/write circuit
11
amplifies write data and provides the amplified write data to the magnetic head
6
. The read/write circuit also restores an original signal by processing read signals.
A description will now be given, with reference to
FIG. 2
, of the read/write circuit
11
.
FIG. 2
is a block diagram of the read/write circuit
11
of the conventional floppy disc drive
1
.
The read/write circuit
11
comprises a flip-flop
21
which hold the write data; a write amplifier
22
which amplifies the data held by the flip-flop
21
; a preamplifier
23
which amplifies read signals detected by the magnetic head
6
; a low-pass filter
24
which cuts off a high-frequency component of read signals amplified by the per-amplifier
23
; a differentiating circuit
25
which differentiates the read signals output from the low-pass filter
24
; a zero-cross comparator
26
which detects a zero-crossing point of the differentiated signal output from the differentiating circuit
25
; and a waveform shaping circuit
27
which shapes an output waveform of the zero-crossing comparator
26
. The waveform shaping circuit
27
includes a time domain filter (TDF)
25
which removes a noise component from the output signal of the zero-cross comparator
26
.
A description will now be given, with reference to
FIG. 3
, of an operation of the read/write circuit
11
.
FIG. 3
is a waveform chart of an operation of the read/write circuit of the conventional floppy disc drive. FIG.
3
-(A) shows the write data provided to the flip-flop
21
; FIG.
3
-(B) shows output data of the flip-flop
21
; FIG.
3
-(C) shows a head write current; FIG.
3
-(D) shows a state of magnetization of the disc
5
; FIG.
3
-(E)shows a head read voltage detected by the magnetic head
6
; FIG.
3
(F) is an output of the differentiating circuit
25
; FIG.
3
(G) shows an output of the comparator
26
; and FIG.
3
-(H) is an output of the waveform shaping circuit
27
.
The write data shown in FIG.
3
-(A) is held by the flip-flop
21
as shown in FIG.
3
-(B), and is converted into a waveform which can easily magnetize the disc
5
. The signal shown in FIG.
3
-(B) is provided to the magnetic head
6
as a write signal which has a waveform as shown in FIG.
3
-(D) so as to magnetize the disc
5
. It should be noted that the disc
5
is magnetized as shown in FIG.
3
-(D) by the waveform shown in FIG.
3
-(C).
When a magnetization pattern shown in FIG.
3
-(D) is scanned by the magnetic head
6
, a voltage shown in FIG.
3
-(E) is obtained. At this time, the magnetic head
6
generates a current at positions where the magnetization is changed. The read voltage of the magnetic head
6
is influenced by a state of the immediately preceding magnetization, and shows relatively gentle changes as shown in FIG.
3
-(E). The read voltage generated by the magnetic head
6
is differentiated by the differentiating circuit
25
, and the signal shown in FIG.
3
-(F) is obtained. At this time, since the read voltage generated by the magnetic head
6
gently changes as shown in FIG.
3
-(E), the signal obtained by the differentiation has relatively small flat portions as shown in FIG.
3
-(F).
The signal shown in FIG.
3
-(F) is subjected to a d
Anderson Kill & Olick P.C.
Cabeca John W.
Chace Christian P.
Teac Corporation
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