JP3388996B2 - Magnetic information processing device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic information processing apparatus applied to magnetic card processing in a toll machine or the like. 2. Description of the Related Art Conventionally, in a toll machine for processing a magnetic card such as a toll ticket or a bar code coupon, magnetic data recorded on the magnetic card is read by a magnetic data reading circuit shown in FIG. Processing. That is, magnetic data recorded on a magnetic card is read by a magnetic head 1 and read by an amplifier 2
And input to the differentiating circuit 3 and the level detecting circuit 4. The signal differentiated by the differentiating circuit 3 is output to a peak detecting circuit 5
, A peak value is detected and sent to the level correction circuit 6. The level correction circuit 6 corrects the peak value detected by the peak detection circuit 5 based on the detection level output from the level detection circuit 4, and outputs the result to the data processing circuit. In the conventional magnetic data reading circuit, when recording data is read from a magnetic card such as a toll ticket or a bar code coupon, the magnetic writing state satisfies a certain reference level. There is a need. However, when the recorded data on the magnetic card is actually read, if the magnetic card is deformed, flawed or dirty, or the transport state of the card is uneven, the output of the read magnetic head 1 is used as a reference. A slight deviation from the level may cause a read error. The above-mentioned read error occurs because the read signal from the read magnetic head 1 is treated as a signal satisfying a certain standard, and the amplification factor, slice level, hysteresis and the like in the magnetic data read circuit are fixed. It is. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and is capable of accurately reading even if the signal level of the magnetic data is low or the magnetization state is bad due to a deformed card or dirt. It is an object to provide an information processing device. According to the present invention, there is provided a magnetic information processing apparatus comprising: a magnetic head for reproducing magnetic recording data of a magnetic card; an amplifier for amplifying data reproduced by the magnetic head; An A / D conversion circuit for converting a signal amplified by an amplifier into digital data;
A memory for storing digital data converted by the conversion circuit, and a peak value of the digital data stored in the memory is detected, and standardization is performed based on a difference between an average value of the positive peak value and an average value of the negative peak value. Means for obtaining a parameter for normalization, a standardizing means for normalizing the digital data stored in the memory based on the parameter for normalization, and Slice by dividing parameter by constant
A level comparison data generating means for setting a level and performing level comparison to generate level comparison data; determining a difference between the standardized data and determining an effective area of the difference data based on the level comparison data; A reproduction data generating unit for generating reproduction data, and a unit for comparing the reproduction data with discrimination data to determine read data are provided. (Operation) Magnetic data recorded on a magnetic card is reproduced by a magnetic head, converted into digital data by an A / D conversion circuit, and stored in a memory. Then, the peak value level is obtained from the digital data stored in the memory, converted to a standard level, and the slice level is set accordingly. Thereafter, level comparison is performed to create pre-processed data, and differentiated to create playback data. The read data is determined by comparing the reproduced data with the discrimination data. By determining the read data as described above, it is possible to accurately read the magnetic data even when the signal level of the magnetic data is low or the magnetization state is bad due to a deformed card or dirt. It becomes possible. An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a magnetic information processing apparatus according to an embodiment of the present invention. In FIG. 1, 11
A read magnetic head reads data recorded on a magnetic card and outputs the data to a sample and hold circuit 13 via an amplifier 12. This sample and hold circuit 13
Sample and hold the read signal amplified by the amplifier 12, that is, the analog signal, with the clock pulse from the clock generation circuit 15 and output it to the A / D conversion circuit 14. The A / D conversion circuit 14 converts an analog signal sent from the sample and hold circuit 13 into digital data by a clock pulse from the clock generation circuit 15. This digital data is captured by a digital signal processor (DSP) 16 and stored in a dual memory 17. The digital signal processor 16 and the dual memory 17 are connected to the system bus 1
8 is connected. The dual memory 17 has two parts, the digital signal processor 16 and the system bus 18.
A memory that can be accessed from any direction. The system bus 18 includes parallel input / output devices 20, 21.
And the CPU 22 are connected. Parallel input / output device 20
Is connected to an insertion detection unit 23 for detecting insertion of a magnetic card.
Is connected. When a detection signal is sent from the insertion detection unit 23, the parallel input / output device 20 inputs the detection signal to the CPU 22 via the system bus 18 and
An operation command is output to the clock generation circuit 15. CPU2
When a card insertion detection signal is sent from the parallel input / output device 20, the motor drive circuit 24 operates to drive the magnetic card into the processing device. FIG. 2 shows an example of the configuration of a magnetic card processing device incorporating the above magnetic information processing device. FIG.
In the figure, reference numeral 31 denotes a housing of the magnetic card processing apparatus, on the front side of which is provided a card insertion slot 32 and a card removal port 33. The housing 31 is provided with a transport path 34 for taking in the magnetic card 30 inserted from the card insertion slot 32, reading recorded data, and returning the card to the card outlet 33. In the transport path 34, the insertion detecting section 23 is arranged at a position close to the card insertion slot 32. The transport path 34 includes a transport roller 35, a transport belt 36, a transport drum 37, and the like.
7 or the transport roller 35 is driven by a motor (not shown) to drive the magnetic card 3 inserted into the card insertion slot 32.
0 is transported by the transport belt 36. Further, a magnetic head 11 for reading recording data of a magnetic card being conveyed is provided on the conveying drum 37 portion. In the above configuration, when the magnetic card 30 is inserted into the card insertion slot 32, it is detected by the insertion detecting section 23, and a card detection signal is input to the parallel input / output device 20. The parallel input / output device 20 transfers the card detection signal to the CPU 22 via the system bus 18 and gives an operation command to the clock generation circuit 15. CP
When the card detection signal is input, the U22 operates the motor drive circuit 24, drives the transport path 34 in FIG. 2, draws the magnetic card 30 into the housing 31, and transports the magnetic card 30 at a constant speed. The magnetic card 3 transported by the transport path 34
0 indicates that the recording data is read by the magnetic head 11.
The data read by the magnetic head 11 is amplified to a certain magnification by an amplifier 12, sampled and held by a sample and hold circuit 13, and further processed by A
The data is converted into digital data by the / D conversion circuit 14.
This digital data is captured by the digital signal processor 16 and stored in the dual memory 17. The data stored in the dual memory 17 is
The processing is performed by the digital signal processor 16 according to the flowchart shown in FIG. The data recorded on the magnetic card 30 is reproduced by the magnetic head 11 as described above. FIG. 4 shows an example of a waveform reproduced by the magnetic head 11.
The data reproduced by the magnetic head 11 is sent to the sample / hold circuit 13 and the A / D conversion circuit 1 as described above.
4 and stored in the dual memory 17 via the digital signal processor 16 (step A1). The data stored in the dual memory 17 is referred to as D ₀ , D ₁ ,
..., if the D _n-1, a digital signal processor 16 examines the peak values from among the data D ₀ ~D _n-1, i.e., the peak values with respect to the reproduced waveform shown in FIG. 4 It detects and calculates the average value (step A2).
When examining the peak value, both the plus peak value and the minus peak value are examined. The range of the digital data Dk is “−2 ⁿ⁻¹ ≦ D _k ≦ 2 ⁿ⁻¹ (where k =
0, x ..., n-1) ". For example, in the case of 8-bit data, n = 8 and the maximum positive number is “2 ⁸ −1 −1 = 12
7 ", and the maximum negative number is" -2 ^8-1 = -128 ". There are various methods for detecting the peak value of the data. For example, first, a digital value is Fourier-transformed as a pre-process, high-frequency components in a frequency domain are removed, and the data is returned to original data by inverse Fourier-transformation to obtain data from which noise components have been removed. Then, for the data from which the noise component has been removed, the difference d
Data values PN _i (i = 0, 1,..., M ₁₋₎ taking D ₀ , dD ₁ ,..., DD _n−1 and changing the positive value of the value that changes from positive to negative to the positive peak value ₁ ) and
A data position MN _i (i = 0, 1,..., M _2-1 ) of a minus value of a value that changes from minus to plus is set as a data position indicating a peak value on the minus side. [0017] The data of the data position PN _i and PD _i, the data of the data position ND _i and MD _i. That is, the peak values of the plus side data are represented by PD ₀ , PD ₁ ,
…, PD _m1-1 , the peak value of the negative data is MD
_0, MD _1, ..., and MD _m2-1. The average calculation of the peak value is as follows: The normalization parameter M is a digital value. If the resolution of the A / D conversion circuit 14 is N bits, D ₀ , D
₁ ,..., D _n are multiplied by “k × 2 ^N / M”. In addition, as a value of k, for example, "0.7-0.
8 ". The normalized data is ND _0-
ND _n-1 . Therefore, the normalized data ND _{0 to} ND
_n-1 can be expressed as _{ND m = D m × k ×} 2 N / M. As shown in FIG. 5, level comparison processing is performed on the standardized data ND _{0 to} ND _{n−1 using the} slice levels Vs + (upper limit) and Vs− (lower limit) to create level comparison data (FIG. 5). Step A4). That is, the level comparison data is “+1” when the captured data is rising within the range of the slice levels Vs + and Vs−, and the level comparison data is “−” when it is falling.
1 ", and the level comparison data is set to" 0 "when it exceeds the range of the slice levels Vs + and Vs-. In this case, the slice level is set to, for example, “Vs + = M / 6, Vs − = − M
/ 6 ". Next, a differentiation process shown in step A5 is performed. In this differentiation processing, the difference data is represented by dND ₀ , dND
_1, ..., when the _{dND n-2, dND m =} ND m + 1 -ND m (m = 0,1,2 the DnD _m, ...,
n-2) That is, dND ₀ = ND ₁ −ND ₀ ,
Difference data is obtained by dND ₁ = ND ₂ −ND ₁ ,. If the level comparison data is "+1" or "-1" with respect to the difference data, it is treated as a dead zone of the data. That is, the difference data dND ₀ , dN
Among D ₁ ,..., DND _n−2 , for example, considering dND _k , if the k-th value of the level comparison data is “+1” or “−1”, the data of dND _k is Treat as a dead band. Thus, the effective area of the differential processing data based on the difference is determined. As the differential processing data , for example, FIG.
Data as shown in (a) is obtained. It should be noted that the hatched area in the figure indicates an area treated as a dead band of data. Then, the differential processing data is subjected to waveform shaping to obtain a zero-crossing signal shown in FIG. Based on the obtained data, “0” or the smallest data position DL _k is found in the continuous data. DL _k (k = 0,
1,..., N−2), Z _k−1 = DL _k −DL _k−1, and when the period of the discrimination data is T, the short period T _s
= T · 1/2, 0.8T _s ≦ Z _k−1 ≦ 1.2T _s is “1” 1.8T _s ≦ Z _k−1 ≦ 2.2T _s is “0” to create a data string (Step A6). For example, taking FIG. 6B as an example, ““ 0 ”,“ 0 ”,“ 1 ”,
"1", "1", "1", "0". Where T
Since there is only one data with the period as
It is regarded as ““ 1 ”,“ 1 ”” → ““ 1 ””. Therefore, the data string is “0”, “0”, “1”, “1”,
"0". Then, the data of the above-mentioned DL _k is shown in FIG.
(Step A7), and check for any inconsistency (Step A8). When it is determined by this check that inconsistency has occurred, normalization processing is performed on the reproduced waveform read data (step A9), and thereafter, the processing returns to step A2 and processing is again performed from the average calculation of the peak values. Then, the above step A
If it is determined in step 8 that there is no inconsistency, the data determination process, that is, the data sequence is set as reproduction data, and the process ends with correct data. As described above, according to the present invention, the reproduced magnetic data is converted into digital data, the degree of the peak value level is determined based on the digital data, and converted into a standard level. Since the slice level is set in accordance with this, even when the signal level of the magnetic data is low or the magnetization state is bad due to a deformed card or dirt, the magnetic data can be read accurately.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a magnetic information processing apparatus according to an embodiment of the present invention. FIG. 2 is a configuration diagram of a magnetic card terminal using the magnetic information processing apparatus according to the embodiment; FIG. 3 is an exemplary flowchart for explaining magnetic read processing according to the embodiment; FIG. 4 is a view showing a reproduction waveform by the magnetic head in the embodiment. FIG. 5 is a conceptual diagram of creating level comparison data. FIG. 6 is a signal waveform diagram for explaining an operation of creating reproduced data. FIG. 7 is a configuration diagram of a conventional magnetic data reading circuit. [Description of Signs] 11 Magnetic head 12 Amplifier 13 Sample hold circuit 14 A / D conversion circuit 15 Clock generation circuit 16 Digital signal processor 17 Dual memory 18 System bus 20 Parallel input / output device 21 Parallel input / output device 22 CPU 23 Insertion Detecting unit 30 Magnetic card 31 Housing 32 Card insertion slot 33 Card outlet 34 Transport path 35 Transport roller 36 Transport belt 37 Transport drum

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G06K 17/00 G06K 7/00 G11B 5/00-5/024

Claims (1)

(57) Claims: 1. A magnetic head for reproducing magnetic recording data of a magnetic card, an amplifier for amplifying data reproduced by the magnetic head, and a signal amplified by the amplifier for digital. An A / D conversion circuit for converting the data, a memory for storing the digital data converted by the A / D conversion circuit, a peak value of the digital data stored in the memory, and an average of the positive peak value Means for obtaining a parameter for normalization from the difference between the value and the average value of the negative peak value; normalizing means for normalizing digital data stored in the memory based on the parameter for normalization; Dividing the standardized parameter by a constant with respect to the data standardized by
Set playback decide the level comparison data generating means for generating a level comparison data by performing level comparison, the effective area of said difference data based on the level comparison data with obtaining the difference between the normalized data A magnetic information processing apparatus comprising: a reproduction data generation unit that generates data; and a unit that compares the reproduction data with discrimination data to determine read data.