KR920005875B1 - Reading method and device for magnetic card - Google Patents

Abstract

Magnetic material having high permiability is printed on a base film and a magnetic material having normal permiability is sprayed on the printed region flatly to record forgery prevention data. A reader detects the residual magnetism difference between the printed region and non-printed region to discriminate the forgery. The method includes: (A) detecting the residual magnetism using a magnetic head, amplifying the detected signal and eliminating noise having high frequency; (B) detecting the variation of the residual magnetic density; (C) modulating the digital signal having TTL level; and (E) reproducing the forgery protecting data.

Description

Method and apparatus for reading permanent signals for preventing magnetic card forgery

1 is a cross-sectional structural view of an embodiment of a magnetic card read in accordance with the present invention.

2 is a waveform diagram showing the residual magnetic flux density of the magnetic card and the output signal when the magnetic flux is detected by the head.

3 is a block diagram showing a schematic configuration of an apparatus of the present invention;

4 is a signal waveform diagram of each part of FIG.

* Explanation of symbols for main parts of the drawings

1: amplification and filter circuit 2: absolute circuit

3: pulse shaping circuit 4: data reproducing circuit

5: clock regeneration circuit

The present invention relates to a method and apparatus for reading out a forgery preventing permanent signal recorded on a magnetic card. As the field of use of magnetic cards expands, countermeasures against counterfeiting are urgently required.

As a result, a new method has been newly proposed by the present applicant to prevent the forgery of the card or the change of the recording information by recording permanent information in a unique manner when applying magnetic material of the magnetic card. And a special magnetic card manufactured for counterfeit identification, in which a specific magnetic material having a high permeability is partially applied to contain a fixed information on a known base film, and a normal magnetic material is applied on the material layer. When applied flatly, upon identification of the card by the magnetic head of the card reading device, forgery identification can be performed by the change of the head output according to the difference in the residual magnetic flux density of the specific and nonexistent portions of the specific magnetic material layer. It is.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and apparatus for preventing counterfeit permanent signal reading of a magnetic card, which makes it possible to accurately read permanent information from a magnetic card on which an anti-counterfeiting permanent signal manufactured by such a method is recorded.

In order to achieve the above object, the present invention comprises two layers of magnetic recording layers for recording permanent information for anti-counterfeiting, one of which is permanent information of a magnetic card formed by partially applying a material having a high permeability to form permanent information. 1. A method of reading a method comprising: a first step of sensing a magnetization state of a magnetic card with a magnetic head, amplifying the signal, and then removing noise of a high frequency component; A second step of indicating whether there is a change in magnetic flux density regardless of the direction of the signal after performing the first step; A third step of converting the signal after performing the second step into a digital signal having a TTL level; And a fourth step of reproducing the permanent information signal using the digital signal after the third step is performed.

In addition, the magnetic recording layer is composed of two layers for recording the anti-counterfeiting permanent information, one of which is a device that reads the permanent information from the magnetic card formed of a material having a high permeability, and detects the magnetization state of the magnetic card. Heads; Amplification and filter means for amplifying the signal output from the head and removing noise of high frequency components; Means for converting an absolute value according to the signal from the amplifying and filtering means to indicate the presence or absence of a change in magnetic flux density regardless of the direction; Pulse shaping means for converting and outputting a signal from said absolute value converting means into a digital signal of a TTL level; And reproducing means for reproducing the permanent information signal using the digital signal from the pulse shaping means.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

One example of the magnetic card to be read of the present invention is to allow permanent information to be recorded with or without magnetic material 2, as shown in FIG. In this case, since magnetic material 1 is a commonly used magnetic recording medium and material 2 is a material having a very high permeability, the plate flux density of such a card is distributed as shown in FIG. (B) of FIG. 2 is an exemplary signal type obtained when reading this by the self head. Here, the information recording method is based on the ISO 3554 standard.

The present invention relates to a method and apparatus for reading a permanent signal for preventing forgery, which makes a microsignal obtained from the above-described card into a digital signal in the form of F2F. The configuration is shown in FIG.

As shown in the figure, the permanent signal reading device for preventing the magnetic card forgery of the present invention includes a known magnetic head for detecting the magnetization state of a magnetic card manufactured in a unique manner as shown in FIG. An amplification and filter circuit 1 for amplifying an input signal and removing noise of a high frequency component, and converting it to indicate whether there is a change in magnetic flux density regardless of the direction of the input signal connected to an output terminal of the amplification and filter circuit. An absolute value circuit 2 to be connected to the absolute value circuit, a pulse shaping circuit 3 for converting an input signal into a digital signal having a TTL level, and an output terminal of the pulse shaping circuit, and receiving data from the digital signal. It consists of a toggle circuit 4 for reproducing and a clock reproducing circuit 5 for reproducing a clock signal.

Now, the process of reading the permanent information from the magnetic card as described above will be described with reference to FIG.

First, the magnetic information recorded on the card is converted into an electrical signal by the head. This signal is in the order of a few mV and is usually mixed with noise. Therefore, it is necessary to amplify the signal to an appropriate size and to remove noise of high frequency components. This function is achieved by the amplification and filter circuit 1 of FIG. At this time, the shape of the signal is as shown in (b) of FIG. Fig. 4A shows the residual magnetic flux density and recording data of the magnetic card recorded by the F2F method.

The pulse shape signal of FIG. 4 (b) shows a change in magnetic flux density. When this signal passes through the absolute value circuit 2 of FIG. 3, a signal as shown in FIG. 4 (c) is obtained. This signal indicates the presence or absence of a change in magnetic flux density regardless of the direction. Then, if the signal is passed through the pulse shaping circuit 3 to convert the signal into a TTL level digital signal, a digital pulse train as shown in FIG. 4 (d) can be obtained. This pulse train is output to the data reproducing circuit 4 and the clock reproducing circuit 5 shown in FIG. 3, whereby data originally written and a synchronous clock can be obtained from this signal. The data reproducing circuit 4 is constituted by a circuit which toggles by an incoming pulse. That is, since these pulses correspond to a transition of magnetic flux degree, the pulses are converted into state transitions of digital signals. Then, the signal of F2F type that can change the data value (0 or 1) as the state change in one cycle can be obtained. The clock regeneration circuit 5 is a circuit for generating a clock that is a reference for determining a data value in synchronization with a data signal. The clock regeneration circuit 5 is composed of a monostable multi-vibrator circuit, and the signal (d) of FIG. 4 is triggered. Used as input At this time, the multivibrator circuit is designed to be triggered only once per period.

From this, the same clock signal as that of the data signal f as shown in FIG. Then, by reading these two signals simultaneously from the CPU (not shown) connected to the rear end, it is possible to cleanly read the permanent information recorded on the magnetic card as described above.

The present invention is constructed and operated as described above, so that the permanent information recorded in a unique manner in the magnetic card can be accurately read, thereby effectively preventing the forgery of the magnetic card.

Claims (4)

The magnetic recording layer is composed of two layers for recording forgery prevention permanent information, one of which is a method of reading permanent information of a magnetic card formed by permanently applying a material having a high permeability to form permanent information. Detecting a magnetization state of the magnetic card, amplifying the signal, and then removing noise of a high frequency component; A second step of indicating whether there is a change in magnetic flux density regardless of a signal direction after performing the first step; A third step of converting the signal after performing the second step into a digital signal having a TTL level; And a fourth step of reproducing the permanent information signal by using the digital signal after performing the third step. The method of claim 1, wherein the fourth step of reproducing the permanent information signal comprises: a fifth step of reproducing data by toggling in accordance with a digital signal after performing the third step; And a sixth step of reproducing the clock signal according to the digital signal after the third step. An apparatus for reading permanent information from a magnetic card formed of a material having a high permeability, comprising one of two layers of magnetic recording layers for recording forgery preventing permanent information, comprising: a head for sensing a magnetization state of a magnetic card; Amplification and filter means (1) for amplifying the signal output from the head and removing noise of high frequency components; Means (2) for absolute value conversion in accordance with the signal from said amplification and filter means (1) to indicate the presence or absence of a change in magnetic flux density regardless of the direction; Pulse shaping means (3) for converting and outputting a signal from said absolute value converting means (2) into a digital signal of a TTL level; And reproducing means (4, 5) for reproducing the permanent information signal using the digital signal from the pulse shaping means (3). 4. The apparatus according to claim 3, wherein said reproducing means (4,5) comprises: a toggle circuit connected to said pulse shaping means (3) for reproducing data from an input digital signal; And a monostable multivibrator for reproducing a clock signal in accordance with the digital signal from said pulse shaping means (3).

Images