JPH06231313A - Prepaid card inspection method - Google Patents

Abstract

PURPOSE:To provide an inspection method by which the propriety of the format of a prepaid card or the respective bits of information data is surely detected. CONSTITUTION:A defective bit detection processing circuit 4 setting an allowance level LU whose upper limit is an appropriate rate and an allowance level LD whose lower limit is the appropriate rate compared to the standard level LO of the peak values of signal waveforms on the respective bits which a head 31 reads, setting a bit when the peak value of the signal waveform is beyond the range of the allowance levels to be a defective bit, outputting an inhibiting bit signal(INH) to a zerocross point detection circuit 35 and invalidating a zerocross pulse P2 when the inhibiting signal is outputted is added to a conventional inspection device 3. Thus, the reliability of the prepaid card is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prepaid card inspection method.

A predetermined format is set on a prepaid card such as a telephone card, and predetermined information data is recorded in its data portion. In order to ensure the reliability of the prepaid card, the correctness of the format and information data is inspected by an inspection device, and the correct one is on sale.

FIG. 3 exemplifies a prepaid card and its format. In FIG. 3A, a strip-shaped magnetic film 2 is applied to the prepaid card 1, and the format shown in FIG. 3B is set on it. Format is code at the beginning
A gap (GAP) of "0 ... 0" is provided, followed by a start code (STX) of code "FF" and information data "x ...
Data part (DATA), end code (ET
X) and (GAP) is provided at the end. The FM method is used for each code of the format and the information data. FIG. 3 (c) exemplifies a bit pattern of the FM system. It is assumed that a bit having a basic width T ₀ indicates "1" and a bit having a width 2T _{0 which} is twice that of "0". The format and the information data are configured by the combination of.

FIG. 4 shows the block configuration of a conventional prepaid card inspection device 3, and FIG. 5 shows the states of signals and pulses in the inspection. Explaining the inspection method of the prepaid card 1 with both figures, the prepaid card 1 is inserted into the head 31 and each bit is read. For convenience, the arrangement of each bit has the same pattern as in FIG.
The read signals p ₁ , p ₂ , p ₃ ... Of each bit have their peak values adjusted to the standard level L _O by the amplifier 32, and then the half-wave circuit 32a changes the negative half-wave signal to the positive side. Half wave signal is generated, and this is differentiated by the differentiating circuit 33 to obtain the differential waveform shown in the figure. The differential waveform is 0 by the comparator 34
The comparison signal C _s is output after being compared with the level, and this is input to the zero-cross point detection circuit 35 to input the zero-cross pulse p _z.
Is output. The interval of each zero-cross pulse p _z is measured by the pulse interval measurement circuit 36, and the measured interval data D _M and the correct comparison data stored in the memory 37 are compared by the data comparison unit 38, and both match. When it does not match, it is regarded as defective (NG).

[0004]

The above-mentioned format or information data is written to the magnetic film 2 by the write circuit at an appropriate level. When the level of a bit changes and it is read by an actual card reader, a bit error may occur, and such a bit is defective. For example, (referred to as hereinafter simply signal) read signal shown in FIG. 5 p ₃ signal p ₃ shown by a dotted line by the level down '
Suppose that In the above inspection, even if the signal p ₃ 'has a zero-cross pulse p _z detected from the differential waveform and is judged to be normal by comparison with the comparison data, the signal p ₂ ' has its peak value higher than the standard level L _O. Since it is small, it cannot be read by a real card reader, and may be a defective bit. Further, when the signal p ₃ is leveled up to become the signal p ₃ ′ shown by the dotted line, even if the above-mentioned inspection shows that the signal is normal, it may become a defective bit in the actual machine.
Originally, since the differential waveform is proportional to the change in the signal waveform, it is detected regardless of the change in the peak value of the signal waveform, and the above contradiction occurs. From this point of view, the inspection of each bit by the differential waveform is not always reliable and sufficient. Therefore, the peak value of each signal p is detected,
If a means for comparing this with a permissible value is provided and is used in combination with the above-described differential waveform inspection method, the correctness of each bit can be reliably inspected. Based on the above idea, the present invention adds a processing means for detecting the peak value of the signal of each bit and comparing it to the allowable value to the conventional prepaid card inspection device, and can inspect the correctness of each bit without fail. The purpose is to provide a method.

[0005]

SUMMARY OF THE INVENTION The present invention is a method for inspecting a prepaid card, which has a standard level of the crest value of a signal waveform of each bit read by a head with respect to the conventional inspection apparatus described above. By comparison, set the upper limit of the upper limit and the lower limit of the lower limit by an appropriate ratio, and if the peak value of the signal waveform is outside the range of the upper and lower limits, judge this bit as a defective bit. A defective bit detection processing circuit for outputting an inhibit signal to the zero-cross point detection circuit and invalidating the zero-cross pulse at the time when this signal is output is added.

[0006]

In the method for inspecting a prepaid card according to the present invention described above, a defective bit detecting processing circuit is added to the conventional inspecting device to compare with the standard level of the peak value of each signal waveform read by the head. , If the upper limit level and the lower limit level are set by an appropriate ratio and the peak value of the signal waveform is outside the upper and lower limit levels, this bit is judged as a defective bit and a zero cross check is performed. An inhibit signal is output to the output circuit. The zero-cross pulse at the time when the inhibit signal is output is processed as invalid, and the zero-cross pulse at the time when it is not output is validated. The comparison processing of the interval data of the zero-cross pulse can be performed in the same manner as in the conventional case, and the correctness of each bit, that is, the format or the information data can be surely checked.

[0007]

1 shows the configuration of a prepaid card inspection apparatus according to an embodiment of the present invention, in which a defective bit detection processing circuit 4 is added to the inspection apparatus 3 shown in FIG.
The defective bit detection processing circuit 4 includes a digital limit level setting circuit 41, two D / A converters 42a and 42b,
The level comparators 43a and 43b and the NOR circuit 44 are connected and configured as shown. FIG. 2 shows the states of signals and pulses in the above inspection apparatus, and for convenience, the FM code and the waveform of each bit are the same as in FIG. 5 described above. The inspection method of the prepaid card will be described below with reference to FIGS. 1 and 2.

As in the conventional case, each bit of the prepaid card 1 is read by the head 31, and each signal p ₁ , p ₂ , p _{3 is} read.
The peak value of ...... is adjusted to the standard level L _O by the amplifier 32, and then the half-wave circuit 32a generates a half-wave signal in which the half-wave signal on the negative side is made positive, and this is differentiated by the differentiation circuit 33. The differentiated waveform is input to the zero-cross point detection circuit 35 via the comparator 34 and the zero-cross pulse p _z is output. The data comparing section 38 compares the interval data D _M of each zero-cross pulse p _z measured by the pulse interval measuring circuit 36 with the correct comparison data stored in the memory 37. On the other hand, in the defective bit detection processing circuit 4,
Appropriate upper limit levels L _D and lower limit levels L _D are set in advance for the standard level L _O , and these are set in the limit level setting circuit 41, respectively. Each limit level is converted into an analog signal by the A / D converters 42a and 42b, and the level comparator
Input to the – and + terminals of 43a and 43b respectively. On the other hand, each signal p from the amplifier 32 is input to the + terminal and the-terminal, respectively, and since the peak value of the signal p ₃ 'has not reached the lower limit level L _D , the comparison signal C _D is output from the comparator 43b. Further, since the crest value of the signal p ₄ 'exceeds the upper limit level L _U , the comparison signal C _U is output from the comparator 43a. Both comparison signals C _D and C _U are inverted to the negative polarity by the NOR circuit 44 and transferred to the zero-cross point detection circuit 35 as an inhibit signal (INH), and the zero-cross points for the signals p ₃ 'and p ₄ ' corresponding to each INH. Detection is blocked. As a result, the interval data D _M of the zero-cross pulse p _z by the pulse interval measurement circuit 35 differs from the correct comparison data (D ₁ , D _2, etc. in the figure), and the comparison by the data comparison unit 37 indicates that it is OK in the past. Even a prepaid card is judged to be defective by this inspection method and NG is output.

[0009]

As described above, in the inspection method according to the present invention, the crest value of each signal waveform of each bit read by the head is detected by the defective bit detection processing circuit added to the conventional inspection apparatus. With respect to the standard level, set the appropriate upper and lower limit levels and lower and lower limit levels, and if the peak value is outside of these allowable levels, it is regarded as a defective bit and the conventional differential waveform inspection is performed. It was overlooked in the method, the crest value changed and the unreadable bit was detected by the actual card reader, and this can be used in combination with the conventional method to reliably check the correctness of the format or information data, The effect of contributing to the improvement of the reliability of the prepaid card is great.

[Brief description of drawings]

FIG. 1 shows the configuration of a prepaid card inspection device according to an embodiment of the present invention.

FIG. 2 shows waveforms of respective signals and pulses for the FM code of FIG.

FIG. 3A shows an example of a prepaid card 1, FIG. 3B shows an example of a format, and FIG. 3C shows an example of an FM system bit pattern.

FIG. 4 shows a block configuration of a conventional prepaid card inspection device 3.

5 shows waveforms of each signal and pulse for the FM code of FIG.

[Explanation of symbols]

1 ... Pre-paid card, 2 ... Magnetic film, 3 ... Conventional inspection device, 31 ... Head, 32 ... Amplifier, 33 ... Differentiation circuit, 34 ... Comparator, 35 ... Zero cross point detection circuit, 36 ... Pulse interval measurement circuit, 37 ... Memory, 38 ... Data comparison section, 4 ... Defective bit detection processing circuit, 41 ... Limit level setting circuit, 42a, 42b
... A / D converter, 43a, 43b ... Level comparator, 44 ...
NOR _{circuit, p 1 ~p 4, p 2} ', p 3' ... read signal,
p _z ... Zero cross pulse, L _O ... Standard level, L _U ... Upper limit allowable level, L _D ... Lower limit allowable level, C _U , C _D ... Comparison signal, INH ... Inhibit signal, D _M ... Measured interval data, D ₁ , D ₂ , D ₃ ... Comparative data.

Claims (1)

[Claims] 1. A head reads out each bit of a format set in a magnetic film of a prepaid card or information data recorded in a data section of the format,
The read signal waveform of each bit is differentiated, the zero-cross point of the differentiated waveform is detected by the zero-cross point detection circuit, the interval of the output zero-cross pulse is measured, and compared with the correct comparison data. In an inspection device for determining the correctness of information data, the inspection device is allowed to have an upper limit of an upper limit and a lower limit of an upper limit by an appropriate ratio as compared with the standard level of the peak value of the signal waveform of each bit. When a level is set and the peak value of the signal waveform is outside the range of the upper and lower allowable levels, the bit is regarded as a defective bit and an inhibit signal is output to the zero-cross point detection circuit, and the inhibit signal is output. Invalidating the zero-cross pulse at the time of
A defective bit detection processing circuit is added,
Prepaid card inspection method.