Dynamic magnetic information storage or retrieval – Recording on or reproducing from an element of diverse utility – Card
Reexamination Certificate
2002-05-14
2003-05-27
Holder, Regina N. (Department: 2651)
Dynamic magnetic information storage or retrieval
Recording on or reproducing from an element of diverse utility
Card
C360S029000, C360S039000, C235S449000
Reexamination Certificate
active
06570723
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
This invention relates to a reader of digital information record and a digital data reproduction method. More particularly, the invention relates to a magnetic card reader and a magnetic data reproduction method.
The invention relates to a data demodulation method and a demodulator of magnetic record data for demodulating magnetic record data written to various magnetic record media of a magnetic card, etc.
2. Related Arts
Hitherto, a card reader, for example, as shown in
FIGS. 35 and 36
has been known as a card reader for reading magnetic data on a magnetic card. A magnetic card reader
901
comprises a slide groove
903
for inserting and sliding a magnetic card
902
, a magnetic head
904
for reading magnetic data on the magnetic card
902
, and a circuit board
905
for processing a read signal. The magnetic card
902
is formed on a surface with a magnetic stripe
906
where magnetic data is recorded, and the magnetic card
902
is inserted into the slide groove
903
, whereby the magnetic head
904
comes in contact with the magnetic stripe
906
. To read the magnetic data, the magnetic card
902
is inserted into the slide groove
903
and is slid in the arrow direction in
FIG. 35
manually if the magnetic card reader
901
is manual or by a transport roller, etc., if the magnetic card reader
901
is of motor transport type, whereby the relative positions of the magnetic stripe
906
and the magnetic head
904
are moved and the magnetic head
904
reads the magnetic data on the magnetic stripe
906
in sequence. The magnetic data read by the magnetic head
904
is input to a demodulation circuit placed on the circuit board
905
as an analog signal and undergoes waveform shaping in the demodulation circuit and is reproduced as digital data.
A bit tracking system made up of a peak detection circuit and a peak-to-peak interval measuring circuit is generally used as a technique for processing the analog signal read by the magnetic head
904
and converting the analog signal into digital data.
Generally, in record and reproduction apparatus for handling magnetic record media such as a magnetic card, for example, as shown in
FIG. 37
, magnetic record data information (see FIG.
38
(
a
)) consisting of two types of frequencies (F and 2F) in combination written to a magnetic record medium
911
such as a magnetic card is reproduced as an analog signal by a magnetic head
912
, one of signals provided by passing the analog reproduction signal through two amplifiers
913
and
913
undergoes waveform shaping in a comparator
914
to provide binarization data (see FIG.
38
(
e
)), the peak position occurring at the magnetic inversion position of the above-mentioned analog reproduction signal is previously detected by a peak detection circuit
5
comprising a differentiation circuit, an integration circuit, etc., (see FIG.
38
(
c
)), a timing signal (see FIG.
38
(
f
)) at the level corresponding to peak output of the analog reproduction signal is generated by a timing generation circuit
917
in accordance with a peak interval signal (see FIG.
38
(
d
)) provided by waveform-shaping and binarizing the peak position in a comparator
916
, the time interval between the adjacent peak positions is counted using a data discrimination circuit or a CPU
918
, and the magnetic record data is demodulated based on the interval data provided by counting the time interval.
At this time, in the data discrimination circuit or the CPU
918
, reference time &agr;T is set relative to interval data T and the presence or absence of inversion of the signal polarity in the reference time &agr;T is detected, whereby binary determination is made and demodulation data is provided. To perform data demodulation in such a manner, hitherto a bit tracking system, for example, as shown in
FIG. 39
has been proposed so as to cope with fluctuations in the transport speed if a magnetic record medium such as a magnetic card is manually transported particularly in a manual record and reproduction apparatus. In the bit tracking system, for interval data Tk (k=1, 2, . . . ) of the current bit to be demodulated, interval data Tk−1 immediately preceding the interval data Tk is used to set reference time &agr;Tk−1 (½<&agr;<1) and the values are compared with each other in less-than, equal-to, or greater-than relation. According to the bit tracking system, if fluctuation in the transport speed occurs and slight fluctuation occurs in the bit time interval of the above-mentioned reproduction signal, a reference signal is calculated from the immediately preceding bit, whereby occurrence of erroneous read is prevented.
However, in the above-described bit tracking system, the magnetic data cannot be read if the speed of the magnetic card
902
is remarkably lowered or the magnetic card
902
stops; this is a problem. If the magnetic card reader
901
is manual, it is difficult for a human being to handle the magnetic card
902
at constant speed, and the speed may become low, causing a read error to occur. Particularly, a person unfamiliar with handling the magnetic card may shift the card from one hand to the other during inserting the card. At this time, the magnetic card
902
stops completely and thus a read error occurs. If the magnetic card reader
901
is of motor transport type, a read error may also occur partially because of a collision with the transport roller, etc. If the magnetic card
902
is handled at enough speed, a read error may be caused by a flaw made on the magnetic stripe
906
, disturbance noise, etc. If a read error occurs even in a part of the read data, the magnetic card reader
901
in the related art needs to again read the magnetic card
902
.
When such a read error occurs, if the manual card reader
901
is a card reader for use with both the magnetic stripe
906
and an IC chip, a case where the operator is prompted to take out the card
902
and the magnetic data is read when the card is taken out or a case where control is transferred to communication processing with the IC chip is possible. However, in the former case, the transition timing to the communication processing with the IC chip does not exist and the operator must be made to again insert the card
902
for the communication processing with the IC chip. In the latter case, if an IC chip does not exist or communications cannot be conducted or the IC chip is not supported, the magnetic data is read again at the taking-out time and processing is continued or the operator must be made to again insert the card
902
. As a message for prompting the operator to perform the next operation and error handling are thus provided in agreement with a possible situation, the processor becomes complicated and ease of operation of the card reader also worsens.
On the other hand, placing strict requirements on handling the magnetic card
90
and the quality of the magnetic stripe
906
to prevent such a read error involves a problem from the viewpoint of ease of operation of the card reader.
Also in the bit tracking system with the immediately preceding data as the reference, if the transport speed of a record medium such as a magnetic card fluctuates rapidly, it is made impossible to follow the speed fluctuation and it is feared that erroneous read may be incurred. For example, interval data T4 in
FIG. 39
is a “1” signal correctly, and essentially the signal polarity should be inverted within the time range of the reference time &agr;3T set based on the immediately preceding interval data T3. In fact, however, the time interval may be prolonged largely because the above-described manual system, etc., is adopted; consequently, inversion of the signal polarity does not take place within the time range of the reference time &agr;3T and the original correct “1” signal is read erroneously as a “0” signal. If an automatic system using motor drive is adopted, there is also a possibility that similar erroneous read will occur.
Further, if the passage speed of a magn
Hoson Keiji
Morozumi Shinya
Nakamura Hiroshi
Yokozawa Mitsuo
Holder Regina N.
Kabushiki Kaisha Sankyo Seiki Seisakusho
Sughrue & Mion, PLLC
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