JPH0685261B2 - Signal read / write determination circuit device for magnetic medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a reproduction signal obtained by scanning a magnetic medium with a read magnetic head, and provides data information and clock information included in the signal. In addition to reading as a data signal and a clock signal respectively, writing processing is performed on the magnetic medium in synchronization with this reading operation, and it is further determined whether or not the written data is correct and then output to the outside. And a signal read / write determination circuit device.

<< Prior Art >> When writing information on a magnetic medium such as a magnetic card, the state of magnetization on the magnetic material is either + Br or −Br (Br: remanent magnetization). Or it must correspond to 0.

There are several methods for dealing with this, and the main ones are RZ method, RB method, NRZ method, NRZI.
The system, PM system, FM system, etc.

Of these, the ones that are actually being used today are
The NRZI method is used when the writing density is relatively low, and the PM or FM method is used when the writing density is relatively high.

And the above PM method (also called phase modulation method, PE method)
And FM system (also referred to as frequency modulation system) correspond to a self-periodic magnetic recording system having data information and clock information in one track.

Here, in the PM system, in a bit cell that is a recording area as unit information on a magnetic medium, there is always a magnetization reversal at the center, and this is used as clock information,
The two directions of magnetization reversal, that is, S → N and N → S are made to correspond to binary numbers of data information.

However, if the same binary number is consecutive as the data information, it is necessary to perform meaningless magnetization reversal at the boundary of each bit cell.

This extra magnetic flux reversal is commonly called a phase magnetic flux reversal or a phase bit.

On the other hand, the magnetic flux inversion having the original information is called data magnetic flux inversion or data bit.

That is, as can be understood from the reproduction signal waveform example obtained by reproducing the PM system magnetic recording shown in FIG. 11, the section A delimited by the alternate long and short dash line is a bit cell, and the level shift that always occurs at the center thereof. Is a meaningful data flux reversal, L →
If the H level transition is data information “1” and the H → L level transition is data information “0”, the reproduced signal waveform is as shown in the data information “1 · 1 · 0 · 1.0 · 0. "Includes.

Also, the level shift that always occurs in the center of the bit cell A is
It is also clock information, and a section T separated by a dotted line in the drawing is a bit period T, and there is a deviation between A and T.

Next, in the FM system, the presence or absence of magnetization reversal in the center of the bit cell A is made to correspond to the binary number of the data information as shown in FIG. 12, and if there is the above magnetization reversal in the center, the data information is "1". If not present, the data information is assumed to be "0", and magnetization reversal is always caused at the boundary of each bit cell A, and this is used as clock information.

That is, the above figure is a reproduced signal waveform obtained by reproducing magnetic recording by the FM system, and the level shift that always occurs at the boundary of the bit cell A is clock information, and the time interval between two consecutive clock information generations. The bit period T indicating “1” matches the bit cell A, and the data information in this case is also “1.1
・ Includes 0, 1, 0, 0 ".

Therefore, in order to read out the data signal and the clock signal from the magnetic recording, two gates are provided so that when one is closed, the other is opened in association with this, and one gate is set to a very short time from the start of the bit period. After a short time
For example, after 1/4 of the bit period has elapsed, the data signal is opened for about 3/4 of the bit period, and the gate B is opened for the rest of the bit period to take out the clock signal. The data information and clock information represented by the level shift in the signal can be read as the data signal and the clock signal.

In this way, in order to read the data signal and the clock signal from the PM system and the FM system magnetic recording / reproducing signal,
Setting the time of 1/4 to 3/4 of the bit period of the reproduction signal has an important meaning, and this time is called "prohibition time".

Then, by controlling the signal reading gate based on the prohibition time, the data signal and the clock signal can be read from the reproduction signal without confusion, and normally the prohibition time is set as a fixed constant value. It

However, the relative speed between the magnetic head and the magnetic medium during recording and reading, that is, the scanning speed, fluctuates under the influence of changes in motor torque and changes in load torque. When the magnetic recording medium is read by a hand-held magnetic card reader or when a magnetic tag is read by a magnetic pen, the scanning speed has a large fluctuation, and the scanning speed becomes faster or slower during one scanning period. .

As described above, when the scanning speed changes, the read bit interval does not become constant. When the scanning speed is high, the bit interval becomes narrow, and when the scanning speed is low, the bit interval becomes wide.

Since the bit period also fluctuates according to the fluctuation of the scanning speed as described above, when the prohibition time of a constant value is set as in the conventional case, the correspondence between the prohibition time and the bit period is broken, and the data information included in the reproduction signal Clock information cannot be read correctly as a data signal and a clock signal.

Therefore, in order to reduce this problem as much as possible, a complicated and expensive constant speed scanning mechanism is installed to suppress fluctuations in scanning speed,
There was no choice but to try to keep the bit period constant.

Therefore, in order to escape from the influence of this fluctuation in scanning speed,
Various methods have been proposed.

That is, when a magnetic medium is automatically conveyed using a motor or the like, a clock signal proportional to the conveyance speed is obtained from an encoder or the like attached to the motor or the conveyance mechanism, and the data signal is read in synchronization with the clock signal. , Or a method in which a proportional time proportional to the preceding bit period or the average bit period of each bit period is obtained by a time setting device, and the read gate is controlled based on this time to read the data signal and clock signal of each bit period. Is.

In such a system, when the magnetic recording density is changed, it is necessary to change the proportional constant of the transport speed (that is, the scanning speed) of the magnetic medium and the clock signal, and the accuracy of the proportional constant is also a problem.

<< Problems to be Solved by the Invention >> The present invention has been studied in view of the above-mentioned problems of the prior art,
Magnetic medium insertion detection sensor, read magnetic head, comparator,
OR circuit, flip-flop circuit, write magnetic head, current driver, write signal processing circuit, write start position setting data memory, read time counter, write time counter, read data memory, By appropriately connecting a central processing unit having a processing data memory, a writing data memory, and a comparison data memory, and by providing the central processing unit with a peculiar calculation determination function, Even if the clock signal from the encoder attached to the transport mechanism is not required at all, even if the bit period fluctuates, the correct data signal and clock signal can be read from the playback signal, and it is synchronized with the read operation. Read and write with higher precision and wider range of bit period fluctuations. Read new was to be able to respond,
The aim is to provide a writing scheme.

<< Means for Solving Problems >> In order to achieve the above object, the present invention provides a central processing unit with a magnetic medium detection signal from a magnetic medium insertion detection sensor and a reading for detecting the magnetization state of the magnetic medium. The read signal obtained by the magnetic head for use is compared with the positive level and the negative level, and all the pulse signals as the OR signal of the positive pulse and the negative pulse output from each comparator and the relevant positive pulse and the negative pulse are set. , A reproduction signal output from a flip-flop circuit as a reset signal is input, respectively, and the read magnetic head and the recording spaced apart from the head by a predetermined distance from the magnetic medium insertion detection sensor in the transport direction of the magnetic medium. A magnetic head for writing is arranged, and the magnetic head for writing is connected to the central processing unit in sequence through a current driver and a signal processing circuit for writing. Calculated in the processing unit, the recording density of the magnetic media, which can be set and the write start position setting data memory required value of the distance or the like between the magnetic head and the magnetic write head for reading, reading time coefficient multiplier,
The write time coefficient unit, the read data memory, the processing data memory, the write data memory, the comparison data memory, and the all data output terminals are connected to each other, and all pulse signal inputs are input to the central processing unit. Disturbance judgment removal function by detecting whether or not the reproduction signal level is reversed, and large pulse interval fluctuation judgment that ignores all pulse signals under the sudden change condition when the transport speed suddenly changes when the magnetic head for reading the magnetic medium enters And a reading function for converting the above pulse interval into binary information, which is determined as either "1" or "0" based on the previous bit cell interval based on the pulse interval value obtained by the reading time calculator. And a data block discriminating function for detecting which block of the data blocks of the magnetic medium is being input, and the write start position setting memory. The function of determining the start time of writing in the data block of the magnetic medium by the input from the above, and the function of performing the writing procedure by the writing magnetic head by using the latest bit cell interval calculated from the reading magnetic head. Further, when only the data of the above-mentioned reading is stored in the reading data memory, the processing processing is performed by the processing data memory according to each condition stored in advance. The next write data and the comparison data after writing, which are created by, are input to the write data memory and the comparison data memory, respectively, and the read data regarding the contents of the write processing and the data of the comparison data memory are written. If the correct data writing is confirmed, it is processed from all the data output terminals. It is intended to provide a signal reading and writing determining circuit of the magnetic medium, characterized in that so as to output the result.

<< Embodiment >> When the present invention is described in detail with reference to the illustrated embodiment, an electric circuit configuration as shown in FIG. 1 is provided, and the central processing unit CPU executes the determination procedure shown in the flowcharts of FIGS. It is possible to let it.

In FIG. 1, 1 is the magnetic medium MC shown in FIG.
With a magnetic medium insertion detection sensor that detects the medium when it is inserted into a transport mechanism driven by a motor, etc.
The output is introduced to the central processing unit CPU.

On the other hand, the output of the read magnetic head 2 provided at a predetermined position as shown in FIG. 8 is applied to the comparators 4a and 4b via the amplifier 3,
Output sides of the comparators 4a and 4b are connected to the CPU via the OR circuit 5 and the flip-flop circuit 6, respectively.

Similarly, as shown in FIG. 8 and described later in detail, the write magnetic head 7 provided adjacent to the read magnetic head 2 is connected via a current driver 8 and a write signal processing circuit 9. When connected to the CPU, this CPU has a writing start position setting data memory 10, a reading time counter 11, a writing time counter 12, a reading data memory 13, a processing data memory 14, A write data memory 15 and a comparison data memory 16 are provided, and reference numeral 17 in the figure denotes all data output terminals.

Here, when the information is recorded on the magnetic medium, it is not recorded on the entire surface as is known, but as shown in FIG. 7 (a), each of the preamble, gap, data portion and postamble is recorded. The data is written by dividing it into blocks, and the whole arrayed in such an order is collectively referred to as a data block 18, and the above data portion includes a permanent data portion, a data gap,
In these blocks, subdivided into temporary data part,
The preamble and the postamble are for transmitting the bit period, and are all binary "0" as shown in FIG.

The gap, which is the next block, is a connection from the preamble to the data portion, is composed of a binary number "1", and the number thereof is predetermined, and the permanent data portion is the unique data of the card. Is defined as a "Read Only" area, the temporary data part is an area where "Read / Write" is possible, and the data gap is also "Read / Write (Read / Write)". ) ”In the area where both are possible, the“ write start position ”is shown as a role of connecting the permanent data section and the temporary data section, the data format is predetermined, and the number of each block is all predetermined. Therefore, the above is clearly shown in FIG. 7 (b).

In the present invention, the arrangement of the read magnetic head 2 and the write magnetic head 7 is as shown in FIG.

That is, in this embodiment, the magnetic medium insertion detection sensor 1 of optical type, mechanical type, the magnetic head for writing 7, and the magnetic head for reading 2 are arranged in this order along the transport direction D of the magnetic medium MC. The distance between the heads 2 and 7 is set to 1 (mm).

Here, the data block of the magnetic medium MC is the recording density B (bit /
mm), the number of bits n between the distances of l
Becomes n = 1 × B = N + r (bit), where N; integer N = [l × B] r; decimal point r = l * B- [l × B].

Now, if it is known from which position on the magnetic medium MC the reading head 2 is reading, the writing magnetic head 7
The position on the magnetic medium MC is determined by the two magnetic heads 2,
It can be calculated by using the number of bits n between 7.

On the contrary, the head of the data gap is the write magnetic head 7
It is also possible to calculate the position of the read magnetic head 2 when the value reaches.

Now the beginning of the data gap is counted from the beginning of the gap
Assuming the Nxth position, the write magnetic head 7 reaches the head of the data gap when the read magnetic head 2 reaches the position Nx− (N + γ) from the gap head position.

Here, the above Nx, N and γ are stored in the above-mentioned write start position setting data memory 10 as data for instructing the write start position to the write magnetic head 7.

Here, in the present invention, as will be described in detail later, first, reading (Read) of the magnetic medium recording by the read magnetic head 2 is performed, and then data processing (Data) by the reading is performed.
Processing), and further, after the writing (Write) by the writing magnetic head 7, the procedure of comparing and collating whether or not the matter to be written was correct is sequentially processed. In order to perform such processing. In the case of the head arrangement according to the embodiment shown in FIG. 8, the magnetic medium must be transported as follows.

That is, (a) first, the magnetic medium MC is conveyed to the read magnetic head 2 to read the contents, and (b) the medium is then conveyed in the opposite direction and returned to before the write magnetic head 7. Then, (c) while carrying the sheet again in the forward direction, writing is performed by the writing magnetic head 7 while confirming the writing position by the reading magnetic head 2 and the bit interval described later in the same manner as described above. ) And the correctness of the written contents is collated as described later.

This is a complicated operation, and a magnetic medium such as a magnetic card goes back and forth in the magnetic card reader / writer.

Therefore, if it is desired to avoid such a reciprocation of the magnetic medium, another object (not shown) for reading may be added between the magnetic medium insertion sensor 1 and the writing magnetic head 7 to achieve the object. You can

That is, by doing so, (a) the additional read magnetic head reads the content and processes the data, and (b) the read head placed after the write head 7 is read. While the writing magnetic head 7 is performing the writing while the writing magnetic head 2 is confirming the writing position and the bit interval as before, (c) the newly written contents may be compared and collated.

Therefore, even in this case, by electrically switching the two read magnetic heads, the processing method can be treated in exactly the same way as in the case of one head.

Therefore, in the present invention, when a medium is detected by the magnetic medium insertion detection sensor 1, the state where the input of "0" was made last time is set, and as shown in the flowchart of FIG. The state of waiting for the output of the pulse signal P is set.

When the magnetic medium is carried to the position of the read magnetic head 2 by a carrier device or the like, the reading of data starts.

Therefore, if the magnetic medium is in the magnetized state as shown in FIG. 2, the read signal P1 from the head 2 is obtained, amplified, and then applied to the comparators 4a and 4b. As the output of the result compared with the level,
The positive pulse P2 and the negative pulse P3 are obtained from b, and at this time, the respective pulses P2 and P3 have the magnetization state of the magnetic medium S →
It occurs when changing from N to N → S.

The P2 and P3 are applied to the OR circuit 5 and the flip-flop circuit 6, respectively.
The magnetization change signal which is the OR signal, that is, all the pulse signals P are input to the CPU, and the output of the flip-flop circuit 6 having the positive pulse P2 as a set input and the negative pulse P3 as a reset input is reproduced. Signal P, also CP
The CPU is able to read all the pulse signals P and the reproduction signal RP as described below, and the read data is stored in the read data memory 13. Becomes

Here, the central processing unit CPU according to the present invention is first provided with a disturbance determination removal function as shown below.

That is, every time all pulse signals are input to the CPU, the CPU checks whether or not the level of the reproduction signal RP at that time is inverted with respect to the level at the previous input of all pulse signals P,
The validity of all the pulse signals P input this time (whether they are regular all pulses or disturbance) is checked.

That is, since the positive pulse P2 and the negative pulse P3 arrive alternately, the output of the flip-flop circuit 6 must be inverted when all the pulse signals P are input.

Therefore, the level of the reproduction signal RP at the time of inputting the whole pulse signal P this time is set to the reproduction signal at the time of inputting the previous whole pulse signal P
If it is inverted when compared with the level of RP, if all the normal pulses (= magnetization change signal) are the same, it is judged as a disturbance such as noise, and if it is a disturbance, it is not accepted.

Secondly, the CPU has a function for determining a large variation in pulse interval.

This is because when the magnetic medium enters between the reading magnetic head 2 and a known pressing roller, the transport speed of the medium suddenly decreases for a moment, and the degree of this decrease changes with each entry. Focusing on the fact that the pulse interval near the beginning of the preamble becomes extremely unstable, this is a function provided to avoid the effect of a large pulse interval variation at the time of this approach.

That is, if the pulse signal P is a normal full pulse signal P as described above, the clock counter 7 checks the pulse arrival interval t, but when the first pulse of the full pulse signal P is input. Is set as if there was a fictitious previous input "0" because it was before the first shot as described above. For the inputs after the second shot, all pulse signals that arrived last time are set. If P is not the first pulse of "1", the pulse that has arrived this time is a pulse after a few pulses counting from the first pulse (it is desirable to set it to an appropriate value of 4 to 9, for example, 6). It is checked whether there is any, and at this time, the next stage processing is performed only for the sixth and subsequent pulses, and the incoming pulse before the fifth is unconditionally determined to be “0”, so that the above function is exerted. is there.

Next, this CPU has a procedure of converting the pulse interval into binary information, that is, a function of determining which of the binary numbers "1" and "0" is read by reading the pulse interval t. .

That is, as explained with reference to FIG. 7 (b) above, the preamble at the beginning of the data block is all 2
Since the decimal number "0" is written, t in the preamble is almost equal to the bit cell interval T.

Then, as described above, read t and use it as the binary number "1".
Which of "0" is to be converted is determined based on the previous bit cell interval T _K-1 .

That is, T _K-1 (1-α) ≦ t _K ≦ T _K-1 (1 + β) ... (a) Where: T _K-1 : Previous bit cell interval T _K : Current pulse interval α, β: Permissible value of pulse interval determined in consideration of recording error on the medium, uneven running speed of the medium, etc. Then, if t _K satisfies the expression (a), it is determined to be a binary number “0”, and if t _K satisfies the expression (b), it is determined to be a binary number “1”. is there.

Further, since t _k that satisfies the expression (b) always arrives twice or more in succession, this may be added to the criterion for determination.

As can be seen from FIG. 5, the interval t _K between the incoming pulses is 2
When the decimal number is “0”, the bit cell interval T _k becomes the reference for the next pulse interval determination.

When the interval t _K between the incoming pulses is a binary number “1”, the pulse intervals for two consecutive pulses are added to form a bit cell interval T, which is used as a reference for the next pulse interval determination.

In this way, the CPU makes the above determination and stores the read data in the read data memory 13.

Further, the data block discrimination function of the CPU checks whether the currently input pulse belongs to the preamble, the gap, the data portion, or the postamble of the data block.

“0” “0”… “0” for a while from the first (first) pulse
Is regarded as a preamble, and is a gap from when "1" is input following the continuation of "0". During this time, "1" continues for a predetermined number.

Counting the number of consecutive "1" s, the data part starts from the next when the number reaches a predetermined number.

The data gap is a predetermined data string, but "0" and "1" occur at random in the permanent data part and the temporary data part.

However, since the total number of "0" and "1" is set in advance, the end of the data part can be known by counting the total number.

Then, it becomes a continuous postamble of "0", but since this part is for protecting the vicinity of the end of the data part when reading the data, it is ignored.

When the read head 2 reaches the head of the data gap, the phase of the reproduction signal is inverted and set as the write polarity signal.

This is to match the magnetization polarity at the start of the next writing process.

That is, since the reproduction signal is created according to the magnetization polarity,
Both phases are the same.

However, in the writing process, writing cannot be performed unless the magnetization is reversed, so that it is necessary to invert the write polarity signal.

Therefore, if the phase is not reversed at the start of writing, the magnetization polarities will not match.

In the data part, "0" and "1" occur at random, but since the total number of "0" and "1" is predetermined, the end of the data part can be known by counting the total number.

Then, it becomes a continuous postamble of "0", but this part is ignored for reading the data because it is only for protecting the vicinity of the end of the data part.

Then, according to the procedure described above, only the data of the data portion is taken out and stored in the read data memory 13, and when all the data of the data portion are stored, this data and the processing data memory 14 are stored in advance. The processing is performed in accordance with the given conditions to create the next write data and the comparison data after writing, and these are stored in the write data memory 15 and the comparison data memory 16, respectively.

Next, the writing process and the comparison process will be described.

As mentioned above, whether the number of read magnetic heads is 1 or 2
Depending on whether the magnetic medium is reciprocated, whether the magnetic medium is reciprocated or is conveyed straight as it is, but since the processing principle is the same, here, the magnetic medium MC is placed at the read head position 2. The explanation starts from the point when is about to reach.

As described above, the above-mentioned Nx, N and γ are obtained from the memory 10 for writing start position setting data.

Thus, the write operation start position Nx− (N + γ) = Nx− (N + 1) + (1−γ) is calculated.

Here, NX− (N + 1) is the number of bits from the beginning of the gap, and 1−γ is a fraction from the Nx− (N + 1) th.

This is the same as the above-mentioned method of reading the write data, but in the process, the interval Tk of the incoming pulse is set to the preparation value T′k of the write time, which is the write magnetic head 7 and the read magnetic head 2. Is the use of scanning the same magnetic medium MC.

The read magnetic head 2 moves from the beginning of the gap to Nx- (N +
1) The write magnetic head 7 determines that the distance difference within 1 bit has been reached in the data gap, which is the write start position, when the write magnetic head 7 reaches the write time coefficient unit 12 by the distance difference T'k. Set (1-γ).

The write time coefficient unit 12 notifies the CPU of the end of counting when the set time is reached.

When the end of the first counting is notified, the CPU starts the writing process.

Writing is performed by passing a current through the write magnetic head 7 to magnetize the medium.

If the polarity of the current is reversed, the magnetization will be reversed in the medium.

The write signal switches the current polarity by opening and closing the driver 18 and inverting its polarity.

When the binary numbers "0" and "1" are recorded by frequency modulation, it is performed as shown in FIG.

That is, the write magnetic head current is reversed for the bit cell interval Tk ... "0" recording, and the write magnetic head current is reversed for T'k / 2 ... "1" first recording. Further, the write magnetic head current is inverted for T'k / 2.
This is the second record of "1".

Here, as clearly shown in the above-mentioned read processing, a signal obtained by inverting the phase of the reproduction signal at the head of the data gap is set in advance as the write polarity signal.

When the CPU receives the notification of the end of counting from the write time counter 12, it checks whether the specified number of data has been written, and if the specified number has been reached, the write signal is turned off and the write process is executed. finish.

If the specified number has not been reached, the following processing will be performed.

(A) When the first writing of "1" is set in the previous writing, it is set as the second writing of "1" in the writing time counter 12 by T'k /
Set 2 to invert the write polarity signal and turn on the write signal. (B) If "0" or "1" is set for the previous write, the next data is written from the write data. If it is “0”, it is written in the writing time counter 12 by T′k.
If is "1", T'k / 2 is set, the write polarity signal is inverted, and the write signal is turned on. (C) When "0" is set or the second "1" is set, ( Add one to the number of writes (in the write counter).

Since the bit cell interval T'k during the writing process is always replaced with the latest data in the reading process in which parallel processing is performed, it is possible to cope with the influence of fluctuations in the transport speed and the like.

When the writing process and the reading process are completed, it is collated whether the data read this time and the comparison data match, and if the correct data is written, the read data is output from all data output terminals 17 as the processing result. It will be.

In addition, the error detection will be explained. A Read error It is judged whether the read data is correct, and if the read data is abnormal, it is read and output as an error.

B Write error It is judged whether the written data is correct, and if the written data is abnormal, it is written and output as an error.

C Parity error The data read by the data part is divided into 4 bits, the sum is taken, it is judged as 4 bit comparison data, and if there is an abnormality, a parity error is output.

Further, as a method of not destroying the data, the preamble and the gap data are read by the read magnetic head 2 before starting the writing, and if there is an abnormality, the data is not destroyed because the data is not destroyed and a write error is output.

<< Effects of the Invention >> The present invention is configured as described above, has an appropriate hardware configuration, and has a procedural capability such as that shown in the flowchart in the CPU. The clock signal from the encoder attached to the mechanism is not required at all, and the correct data signal and clock signal can be read from the reproduction signal even if the bit period varies, and the latest magnetic head calculated from the read magnetic head is used. Using the bit cell interval,
By being able to write with a magnetic head for writing,
Reading and writing can be made more precise and correspond to a wide range of bit periods.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a signal read / write determination circuit device for a magnetic medium according to the present invention, FIG. 2 is a signal waveform diagram in the read portion of the device, and FIG. 3 is a signal in the write portion. FIG. 4 is a waveform diagram, FIG. 4 is a flow chart of a reading part which is processed by the central processing unit of the same device, and FIGS. 5 and 6 are flow charts of a writing part and a comparison processing part.
FIG. 7 (a) is an explanatory view of a data block plane of a magnetic medium,
FIG. 8B is an explanatory diagram showing the binary output contents of the same block, FIG. 8 is an explanatory diagram of the arrangement of magnetic heads for reading and writing, and FIG. 9 is reading for converting the pulse interval into binary information. FIG. 10 is a waveform explanatory view showing a procedure of a portion, FIG. 10 is a waveform explanatory diagram of the same in a writing portion, and FIGS. 11 and 12 are reproduction signal waveform explanatory diagrams by the PM and FM magnetic recording systems, respectively. 1 ... Magnetic medium insertion detection sensor 2 ... Read magnetic head 4a, 4b ... Comparator 5 ... OR circuit 6 ... Flip-flop circuit 7 ... Write magnetic head 8 ... Electric driver 9 ... Book Input signal processing circuit 10 …… Write start position setting data memory 11 …… Read time counter 12 …… Write time counter 13 …… Read data memory 14 …… Processing data memory 15 …… Write Embedded data memory 16 …… Comparison data memory 17 …… All data output terminals CPU …… Central processing unit P1 …… Read signal P2 …… Positive pulse P3 …… Negative pulse P …… All pulse signal RP …… Reproduction Signal MC: Magnetic medium l: Separation distance

Claims (1)

[Claims] 1. A central processing unit is provided with a magnetization medium detection signal from a magnetic medium insertion detection sensor and a read signal obtained by a read magnetic head for detecting the magnetization state of the magnetic medium.
All pulse signals as an OR signal of the positive and negative pulses output from each comparator after being compared with the positive and negative levels and the flip-flop circuit that sets and resets the positive and negative pulses. The read magnetic head and the write magnetic head separated from the head by a predetermined distance are arranged in this order from the magnetic medium insertion detection sensor in the direction in which the magnetic medium is conveyed. The built-in magnetic head is sequentially connected to the central processing unit via a current driver and a write signal processing circuit. Further, the central processing unit has a recording density of a magnetic medium, the read magnetic head and the write magnetic head. Write start position setting data memory capable of setting required values such as the distance from the magnetic head for reading, read time coefficient device, write time coefficient device,
The read data memory, the processing data memory, the write data memory, the comparison data memory, and the all data output terminals are connected to each other, and the level of the reproduced signal is inverted every time all pulse signals are input to the central processing unit. Disturbance judgment removal function by detecting whether or not, when the transport speed suddenly changes when the magnetic head for reading the magnetic medium enters, a pulse interval large fluctuation judgment function that ignores all pulse signals under the sudden change condition, and the above pulse interval When converting the data into binary information, the reading function for judging either "1" or "0" based on the previous bit cell interval based on the pulse interval value by the reading time calculator, and the data block of the magnetic medium. A data block discrimination function for detecting which block of the data is being input, and by inputting from the write start position setting memory, It also has a function of determining a writing start time point in a data block of the magnetic medium, and a function of performing a writing procedure by the writing magnetic head by using the latest bit cell interval calculated from the reading magnetic head. , When only the data of the above-mentioned reading is stored in the reading data memory, the processing processing by the processing data memory is performed according to the respective conditions stored in advance, and the next processing created by this is performed. Whether the write data and the comparison data after writing are input to the write data memory and the comparison data memory, respectively, and the read data about the contents of the write process and the data in the comparison data memory match. If the correct data writing is confirmed, the processing result is output from all the data output terminals. Signal reading writing determining circuit of the magnetic medium characterized by the.