JPH06103581B2 - Method of analyzing magnetic recording data - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to magnetic recording data for determining whether or not data continuously recorded on a magnetic recording medium by a frequency modulation method is recorded according to a predetermined standard. Analysis method.

[Prior art and its problems]

In recent years, magnetic cards have been widely used as cash cards, ID cards for identification, time cards, entrance management cards, various membership cards, etc. The company name written on the magnetic stripe that is the magnetic recording medium of this magnetic card. , Magnetic recording data such as personal name or registration number is read by a magnetic card reader to perform predetermined data processing.

By the way, on the magnetic stripe of the magnetic card, the company name,
When writing an individual name or the like, a predetermined character is replaced with a binary code “0” or “1” and recorded by a frequency modulation method.

In this frequency modulation method, when recording data, a magnetic flux reversal is given in each of the clock signal for delimiting each data bit and the data bit indicating the binary code "1",
Each data bit is indicated by giving the magnetic flux reversal of the clock signal at regular intervals, and when there is no magnetic velocity reversal in the data bit, a binary code "0" is indicated, and the magnetic flux reversal is present in the center of the data bit. If it exists, the binary code "1" is indicated.

The recording interval of each of these data bits depends on the JIS standard.
It is regulated within 8.268bit / mm ± 4%, and the data recording interval per bit is about 0.12mm (JIS-B
9561).

Therefore, when a large error occurs in the data recording interval for some reason when recording data on the magnetic card, the magnetic card reader cannot read the data, and the magnetic card cannot be used. However,
In such a case, it was difficult to find the cause.

Therefore, conventionally, by measuring the deviation of the data recording interval of the data bits recorded on the magnetic recording medium of the magnetic card, it is determined whether or not the data is recorded at the correct interval on the magnetic card, and the data cannot be used. It was used as a clue to investigate the cause.

The conventional determination method will be described with reference to FIG. 1. The data recording interval Ti of each data bit is measured, and the data recording interval Ti is compared with a predetermined reference data recording interval Tk. The deviation RTi of the data recording interval Ti was calculated by RTi = (Ti-Tk) / Tk.

As the reference data recording interval Tk, normally, two kinds of values, that is, an average value Tav of data recording intervals of all data bits and a data recording interval Ti ₋₁ of the immediately previous data bit are used. This is based on the difference in how to read data between the electric card reader and the manual card reader.

That is, in the electric card reader, since the card transport speed is substantially constant, the data is read based on the average value Tav of the data recording intervals of all data bits, which is the case in the manual card reader. However, since the card transport speed is not constant, data is read based on the data recording interval Ti _-1 of the immediately previous data bit.

Therefore, the deviation RAi due to the former is expressed by RAi = (Ti−Tav) / Tav [i ≧ 1], and the deviation RBi due to the latter is RBi = (Ti−Ti ₋₁ ) / Ti ₋₁ [i ≧ 2] It is represented by.

Then, by determining whether the deviations RAi and RBi are within a predetermined allowable range, it is determined whether or not each data bit is recorded on the magnetic recording medium of the magnetic card at an accurate interval. It was

However, even if the magnetic card is judged to be normal by the above method, there is a problem that it cannot be actually used.

That is, according to the frequency modulation method, when the binary code “1” is recorded in the data bit, the magnetic flux reversal is given at a half of the data recording interval (0.06 mm). Since only the deviation of the data recording interval Ti is measured in the method, even if the magnetic speed reversal position of the binary code "1" given at the approximate center of each data bit is deviated, this can be detected. I couldn't.

For example, when the binary code “1” is recorded in the second data bit as shown in FIG. 1, the central magnetic flux reversal position P shifts to the P ′ position indicated by the broken line, and the allowable range is Even if there is a deviation that exceeds (± 10% or more),
If the data recording interval T ₂ of the data bit is within the allowable range, the magnetic card is judged to be normal even if it is actually unusable, so it is recorded on the magnetic card. There is a problem that the quality of data cannot be accurately determined.

[Object of the Invention]

Therefore, in addition to the conventional method as described above, the present invention
By also detecting a data defect due to the deviation of the magnetic flux reversal position given by the binary code "1", it is possible to reliably determine whether or not the data is recorded on the magnetic recording medium according to a predetermined standard. It is intended to provide a method of analyzing information.

[Structure of Invention]

To achieve this object, the present invention is a method of analyzing magnetic recording data for determining whether or not data continuously recorded on a magnetic recording medium by a frequency modulation method is recorded according to a predetermined standard. The data recording interval of each data bit recorded on the magnetic recording medium is compared with the data recording interval of the immediately previous data bit and the average value of all data recording intervals to measure the respective deviations and the binary code "1". '' Is measured by comparing the magnetic flux reversal interval before or after in the recorded data bit with the other magnetic flux reversal interval or 1/2 of the data recording interval of the immediately preceding data bit and measuring the deviation. It is characterized in that the amount of each of the three types of deviation is displayed in correlation with the data recording position.

[Operation of the invention]

According to the method of the present invention, the deviation of the data recording interval of each data bit recorded on the magnetic recording medium is measured and
Since the deviation of the magnetic flux reversal interval given by the binary code “1” is also measured, it goes without saying that it is possible to detect the abnormality of the data due to the size of the data recording interval, which is conventionally performed. It is also possible to detect a data abnormality due to the bias of the magnetic flux reversal position given in the data bit in which the binary code "1" is recorded.

In addition, the measured deviation is represented on a graph in which, for example, the amount of deviation is plotted on the vertical axis and the data recording position is plotted on the horizontal axis. You can easily judge with.

〔Example〕

 Hereinafter, the method of the present invention will be specifically described with reference to the drawings.

FIG. 1 is an explanatory diagram showing a relationship between data recorded on a magnetic stripe serving as a magnetic recording medium by a frequency modulation method and magnetic flux.

In the figure, S is an example of the signal waveform of the magnetic recording information recorded on the magnetic stripe of the magnetic card.

I ₁ , I ₂ ... In are magnetic flux reversal intervals recorded on the magnetic card, and when the binary code “0” is recorded in the data bit, the magnetic flux reversal intervals In are the data recording intervals Ti. When the binary code “1” is recorded in the data bit, the magnetic flux reversal intervals In and In _{+ 1} become Zi and Ki, respectively, and the data recording interval Ti of the data bit is Ti. = In + In _{+ 1}

Zi and Ki are the magnetic flux reversal intervals in the first half and the second half when the binary code "1" is recorded in the i-th data bit, respectively.

Deviation RHi of data recording interval in which binary code "1" is recorded
Is defined as RHi = (Ki−Zi) / Zi, where the first half of the magnetic flux reversal interval Zi in the data bit is the reference magnetic flux reversal interval.

Note that Fj is the magnetic flux reversal interval of bits when "0" is recorded in the data bits, and is equal to the magnetic flux reversal interval of each data bit.

FIG. 2 is a block diagram showing the basic structure of a magnetic recording data analyzer using the method of the present invention, and FIG. 3 is a flow chart showing the processing procedure thereof.

The magnetic recording data analysis device is provided with at least a control device 4 including a microcomputer having an interface circuit 1, an arithmetic processing device 2 and a storage device 3.

Here, in the interface circuit 1, a magnetic head 7 which is in sliding contact with the magnetic stripe 6 of the magnetic card C on the input side thereof and reads the magnetic flux reversal position recorded in the magnetic stripe 6, and the magnetic card C in the head 7. Is connected to an optical sensor 8 for detecting whether or not the magnetic card C is in sliding contact with the magnetic head C, and a conveying device 9 for sliding the magnetic card C in contact with the magnetic head 7 at a constant speed, and a CRT display 10. ,
The printer 11 and the like are connected.

Since the magnetic card C is not conveyed by the conveying device 9 at a constant speed (for example, 19 cm / s), a clock (not shown) is activated each time the magnetic head 7 detects the reversal of magnetic flux to measure the time. , The magnetic flux reversal interval In will be expressed in time. If the signal is recorded according to JIS when the magnetic card C is transported at 19 cm / s, the data bit interval Ti is about 637 μs, and the data bit recorded with the binary code “1” is Magnetic flux reversal interval Zi and Ki is about 318μ
s.

The arithmetic processing unit 2 executes a predetermined arithmetic processing based on all the magnetic flux reversal intervals In read from the head 7,
The deviations RAi, RBi of the data recording intervals and the deviation RHj of the magnetic flux reversal intervals of the data bits in which the binary code “1” is recorded are calculated, and the abnormality of the data recorded in the magnetic card is detected based on these values. , Output its detection.

The storage device 3 stores a processing program necessary for the arithmetic processing of the arithmetic processing device 2 and processing data necessary in the arithmetic processing process, and also temporarily stores the arithmetic processing result.

The processing procedure of the arithmetic processing unit 2 will be described below based on the flowchart shown in FIG.

Here, the steps from step to step are the procedure for reading the magnetic flux reversal interval In of the signal waveform S stored in the magnetic stripe 6 of the magnetic card C, the steps from step to step are the binary code determination means, and the steps from step to step. The above are the data defect detecting means.

When a switch (not shown) is turned on, the analyzer is started and the processing shown in FIG. 2 is started, and it is determined whether or not the magnetic card C to be analyzed in step 1 is inserted into the insertion port (not shown). It is determined whether or not the magnetic card C is inserted, the process proceeds to step, and when the magnetic card C is not inserted, the process waits until the magnetic card C is inserted.

Next, in the step, after setting the index n = 1 of the magnetic flux reversal interval In, the process proceeds to the step and the transport device 9
Is driven to convey the magnetic card C at a constant speed (for example, 19 cm / s), and the process proceeds to step.

When magnetic flux reversal is detected by the magnetic head 7 in step, the process proceeds to step and a clock (not shown) provided in the control device 4 is operated to start timing of a time indicating the magnetic flux reversal interval In.

Then, when the next flux reversal is detected in step,
After shifting to the step, the clocking is temporarily stopped, and the time at that time is stored as a magnetic flux reversal interval In in a predetermined storage area of the storage device. Then, in step, the clock is reset, and in step, index n = n
After replacing with +1, the process returns to the step again to start measuring the next magnetic flux reversal interval In.

When the magnetic flux reversal is not detected in the step, the process shifts to the step to determine whether or not the reading of the magnetic flux reversal interval In is completed.

This judgment is made by judging whether or not the magnetic stripe 6 of the magnetic card C is in sliding contact with the magnetic head 7 based on the output of the optical sensor 8. When the magnetic stripe 6 is still in sliding contact with the magnetic head 7, the process returns to the step. When the magnetic card C passes through the magnetic head 6 and the reading of the magnetic flux reversal interval In is completed, the process proceeds to the step. Then, the driving of the carrier device 9 is stopped and the operation of the clock is stopped, and the process proceeds to the step to store the value ne of the index n of the last magnetic flux reversal interval In, and then to the binary code determination means after the step. Transition.

That is, since the magnetic flux reversal interval In is read regardless of the stored binary code “0” or “1”, whether the data recorded in the data bit is “0” or “0” based on the read data. 1 "is determined, and the magnetic flux reversal intervals Zi, Ki, etc. when the data recording interval Ti and the binary code" 1 "are recorded for each data bit are obtained.

First, in step, the index i of the data recording interval Ti
= 0, the magnetic flux reversal interval Fj of the data bit in which "0" is recorded
Index j of 0, index n of magnetic flux reversal interval In
After setting = 1 and setting s = 1, the process proceeds to step and the magnetic flux reversal interval In stored in the storage device 3 is called.

Next, in step, it is determined whether the data bit including the magnetic flux reversal interval In is “0” or “1”. In this determination, the magnetic flux reversal interval In is compared with a preset interval I (637 μs), and for example, it is determined to be “0” if In> 0.7I and “1” if In ≦ 0.7I.

If it is determined to be "0", the process shifts to the step, the index i = i + 1, j = j + 1 is replaced and s = 1 is set, and then the process shifts to the data recording interval Ti = In and "0". The magnetic flux reversal interval Fj of the data bits in which “” is recorded is set to Fj = In, and Ti and Fj are stored in a predetermined storage area of the storage device 3.

If it is determined to be "1" in the above step, the process proceeds to step to determine whether the magnetic flux reversal interval In is the first half magnetic flux reversal interval Zi or the second half magnetic flux reversal interval Ki of the data bit. judge. This determination is made based on the value of s. The first half is set when s = 1 and the second half is set when s = 2.

When it is determined that s = 1, the process shifts to the step, the index i = i + 1 is replaced, and in the step, the first half magnetic flux reversal interval Zi = In is stored in a predetermined storage area of the storage device 3, Replace s = 2 in step.

Further, when s = 2 is determined in the above step,
In the step, the latter half magnetic flux reversal interval Ki = In is set, and in the step, the data recording interval Ti = Zi + Ki of the data bit is calculated and replaced with s = 1 to store the Ki and Ti in a predetermined storage area.

Then, the process shifts to the step or to the step, and it is determined whether or not the processing has been completed for all the magnetic flux reversal intervals In. This determination is performed by determining whether the value of the index n is equal to the final value ne stored in the step. When n ≠ ne, the process proceeds to the step and replaces n = n + 1 and then returns to the step. The process is continued, and when n = ne is reached, the process proceeds to the step, the final value ie of the index i is stored, and then the process proceeds to the data defect detecting means at the step and below.

First, in the step, the average value Tav of the data recording intervals Ti (1 ≦ i ≦ ie) of all the data bits is calculated, and the process proceeds to the step, where the deviations RAi, RBi of the data recording intervals and the binary code “1” are calculated. The deviation RHi of the magnetic flux reversal interval of the recorded data bits is calculated.

Next, the step proceeds to the above deviations RAi, RBi and RHi.
Is within a predetermined tolerance range (for example, within ± 10 to 15%), and if there is a deviation beyond the tolerance range,
By moving to a step and outputting a predetermined error message to the CRT display 10 or the printer 11, issuing a predetermined buzzer sound, or displaying an LED for lighting, it is possible to detect that there is a data abnormality in the card C. Notify and move to step.

If there is no deviation exceeding the permissible range, the process proceeds to step, and predetermined data is output according to an instruction from a switch, a keyboard (not shown) or the like, and the process ends.

The output contents of the steps include, for example, deviations RAi, RB
As shown in Fig. 4, each deviation is displayed in dots on the graph with the data bit recording position on the X-axis and the deviation value (%) on the Y-axis so that the distribution state of i and RHi can be seen at a glance. . At this time, when a deviation exceeding the display range of the graph occurs, the deviation is output on the upper limit line U or the lower limit line D of the graph.

Also, the magnetic flux reversal interval of the data bit in which "0" is recorded
The maximum value, the minimum value, and the average value of Fj, the magnetic flux reversal intervals Zi and Ki in which “1” is recorded, and the data recording interval Ti are output in μs units.

Further, the data recorded in each data bit is replaced with the binary code “0” and “1” and output.

Hereinafter, the method of the present invention by the recording information analyzing apparatus configured as described above will be described with reference to FIG.

First, when a switch (not shown) is turned on and the magnetic card C on which the signal waveform S is recorded is inserted into the insertion opening of the analyzer, the carrier device 9 is driven and the magnetic head 7 detects the magnetic flux reversal of the signal waveform S. Each time, the clock is activated and the magnetic flux reversal interval In is measured in time and stored in the storage device 3 [steps-].

In the signal waveform S, since "0" is recorded in the first data bit, the first magnetic flux reversal interval I ₁ ≈I.
Therefore, I ₁ > 0.7I and the magnetic flux reversal interval I ₁ is “0”.
Is treated as the magnetic flux reversal interval constituting the data bit [step], and I ₁ is stored in the storage device 3 as the data recording interval T 1 of the data bit and the magnetic flux reversal interval F ₁ of the data bit in which “0” is recorded. [Step] Next, since “1” is recorded in the second data bit, the magnetic flux reversal interval I ₂ ≈I / 2. Therefore, I ₂ ≦ 0.7I, and the magnetic flux reversal interval I ₂ is treated as the magnetic flux reversal interval constituting the data bit of “1” [step]. At this time, the value of s is s = 1 in steps.
Therefore, the magnetic flux reversal interval I ₂ is stored as the magnetic flux reversal interval Z ₂ = I _{2 in} the first half of the data bit [step].

Then, the next magnetic flux reversal interval I ₃ is also treated as the magnetic flux reversal interval that constitutes the data bit of “1” [step], but at this time, the value of s is set to s = 2 in step, The magnetic flux reversal interval I ₃ is stored as the magnetic flux reversal interval K _{2 in} the latter half of the data bit (step),
Further, the data recording interval T ₂ of the data bit is stored as T ₂ = Z ₂ + K ₂ [step].

Then, all the input magnetic flux reversal intervals In (n = 1 to n
The above processing is repeated for e), and the data recording interval T
At the same time that the average value Tav is calculated [step] based on i, the deviations RAi, RBi and RHi are calculated based on the average value Tav, the data recording interval Ti and the magnetic flux reversal interval Ki, Zi, RAi = (Ti-Tav) / Tav RBi = (Ti-Ti _-1 ) / Ti _-1 RHi = (Ki-Zi) / Zi Calculate [step], if each deviation exceeds the allowable range (for example ± 10 to 15%) Error message is output to detect that the magnetic card C has a data error [step-].

As described above, according to the magnetic recording data analysis method of the present invention, not only the deviations RAi and RBi of the data recording intervals of the respective data bits, which have been conventionally measured, but also the binary code “1” is used.
Since the deviation RHi of the magnetic flux reversal interval of the recorded data bit is also measured, not only the data defect due to the error of the data recording interval Ti but also the conventional analysis method cannot detect it. It is also possible to detect a data defect due to the deviation of the magnetic flux reversal position of the binary code “1”, and therefore it is possible to correctly determine whether or not the magnetic card can be normally used.

Further, according to the present embodiment, since the distribution state of each deviation is visually displayed by a graph or the like, when the magnetic card is judged to be not normal, it is possible to judge at a glance the defective portion of the data and its degree. You can Even when there is no data abnormality, the performance of the encoder that inputs data to the magnetic card C can be known by examining the result.

Further, when detecting the magnetic flux reversal of the signal waveform S recorded on the magnetic card C and measuring the magnetic flux reversal interval In, if the direction of the magnetic flux reversal and the pulse height are also detected, the continuous signal waveform Data defects due to poor quality of recorded data and recorded magnetic field strength can be determined.

Further, the read magnetic flux reversal interval In is integrated, the product with the transport speed (19 cm / s) of the magnetic card C is calculated, and the recording position of each data bit is calculated, whereby the predetermined data (STX, It is possible to determine whether or not LRC) is recorded at a predetermined position based on a recording format based on JIS-B9561, for example.

Furthermore, all magnetic flux reversal intervals read as needed.
If you output In, by examining the data,
More detailed analysis can be performed.

In the description of the above embodiment, the deviation RHi of the magnetic flux reversal interval of the data bit in which the binary code “1” is recorded is RHi = (Ki -Zi) / Zi, but the present invention is not limited to this, and for example, RHi = 2 (Zi-Ti / 2) / Ti with 1/2 of the data recording interval Ti of the data bit as the reference flux reversal interval. May be defined as follows.

Further, in the embodiment, the case where all the data recorded on the magnetic card C is analyzed has been described, but the LRC code is recorded from a specific range of the magnetic card C, for example, the data bit where the code STX is first recorded. It is also possible to analyze only data up to the data bit.

Furthermore, in the embodiment, the case where the method of the present invention is applied to the analysis of the data recorded on the magnetic card has been described, but it goes without saying that the method of the present invention can also be applied to the analysis of the data recorded on any other magnetic recording medium.

〔The invention's effect〕

As described above, according to the method of the present invention, the deviation of the data recording interval of each data bit recorded on the recording medium is measured, and in addition to this, the magnetic flux reversal interval given by the binary code “1” Since the deviation is also measured, it goes without saying that it is possible to detect the abnormality of the data due to the error of the data recording interval, which has been conventionally performed, and the data in which the binary code “1” is recorded. Since it is also possible to detect an abnormality in the data due to the deviation of the magnetic flux reversal position given between the bits, it is possible to accurately analyze and determine the quality of the recording state of the data on the magnetic recording medium, which is excellent. There is an effect that it is possible to provide effective basic data for estimating the abnormality of the input device for recording magnetic information on the recording medium.

[Brief description of drawings]

FIG. 1 is a diagram showing a signal waveform of magnetic recording information recorded on a magnetic recording medium for explaining the method of the present invention, and FIG. 2 is a basic configuration of an apparatus for analyzing magnetic recording information to which the method of the present invention is applied. FIG. 3 is a block diagram, FIG. 3 is a flowchart showing the processing procedure of the arithmetic processing unit, and FIG. 4 is a graph showing the analysis result of magnetic recording information. Explanation of symbols 4 ... Control device, 7 ... Magnetic head, 8 ... Optical sensor, 9 ... Conveying device, 10 ... CRT display, 11 ...
Printer, S ... Signal waveform, Ti ... Data recording interval, Z
i, Ki, In ... Magnetic flux reversal interval.

Claims (1)

[Claims] 1. A method of analyzing magnetic recording data for determining whether or not data continuously recorded on a magnetic recording medium by a frequency modulation method is recorded according to a predetermined standard. The data recording interval of each data bit is compared with the data recording interval of the immediately preceding data bit and the average value of all the data recording intervals to measure the respective deviations, and the data in which the binary code "1" is recorded. Either the magnetic flux reversal interval before or after in the bit is compared with the other magnetic flux reversal interval or 1/2 of the data recording interval of the immediately preceding data bit, and the deviation is measured, and the deviation of each of the three types of the measured deviations is measured. A method for analyzing magnetic recording data, characterized in that the amount is displayed in correlation with the data recording position.