SU1674228A1 - Digital data write-read method - Google Patents

Abstract

The invention relates to the field of information storage and can be used when recording and reproducing digital information on magnetic media. The goal is to increase recording density. The method consists in that the initial information is previously converted into an even number of successively successive bytes of information with a given number of bits in each byte. Each odd byte is converted into a pulse-width signal. The recording of each pulse-width signal is carried out simultaneously with a change in the magnetization of the magnetic recording medium in one direction. The magnitude of the change in magnetization of the magnetic recording medium is determined by the significance of the even-numbered bytes. The sequence of consecutive bytes of information is divided by a marker signal into cyclic sequences. The recording of the marker signal is carried out by changing the magnetization of the magnetic recording medium of another direction until the corresponding extreme state is reached. During reproduction, demodulation of digital information is carried out taking into account the amplitude of the reproduced signals of information packages and the sequential analysis of the time intervals between adjacent reproduced pulses. As a control, the counting of reproducible pulses is performed. 3 il.

Description

The invention relates to the field of information accumulation, in particular, to methods of recording and reproducing digital information.

The aim of the invention is to increase the reproduction recording density.

FIG. 1 shows a block diagram of an apparatus for carrying out the method: FIG. 2 shows an example of splitting a 16-bit binary code (Fig. 2a) into 8 bytes (Fig. 2.6) in one or three bits (Fig. 2, c) in the corresponding byte; in fig. 3 - timing diagrams explaining the essence of the method in relation to this example.

A device for implementing the method of recording and reproducing digital information contains a buffer register 1, information outputs connected to digital switch 2, one group of outputs of which is connected to the first input of comparator 3, and another to the first adder 4. To another input of comparison block 3 via digital the switch 5 is connected to a binary counter 6, which is controlled by the counter control unit 7. The output of the comparison unit 3 is connected to the input of the control register unit 8 of the shift register 9, the state of which controls the digital switch 10, the information inputs connected to the dial-up field 11, and the output to the second adder 12 whose output controls the digital-analogue

VI

go

N3 00

A second converter (D / A converter) 13, which, in turn, is connected to the 14-item head. The device is controlled in the register mode by the control and synchronization unit 15, one input connected to the crystal oscillator 16, and the other input to the start block 17. The output of block 15 is connected with the control inputs of buffer register 1, binary counter 6, counter control block 7, shift register 9, shift register control block 8, shift register 18, shift register control block 19, whose input is the switch 20 is connected to the binary counter 6. The operation mode of the device is determined by the shift register, which controls the blocks 2,5,7,8,20. Additionally, the output of the first adder 4 is connected to the buffer register 21, the output of which is connected via the key block 22 to the second input of the adder 4. In the receiving part, the device contains a read head 23 connected to the amplifier 4 of the pulse signals whose output is connected to the inputs of the polarity discriminator 25, amplitude detector 26 and timer 27, the outputs of which are connected to the input of the transmitter 28.

The method with this device is carried out as follows. The original N-bit binary code (16 bits in the example shown in Fig. 2) is entered in the buffer register 1. The division of the N-bit binary code into Ne bytes (8 bytes 1 and 3 bits in the corresponding j byte) is carried out via digital switch 2, which has two groups of output buses. In fact, the separation of the original binary M-random code into Ne bytes means the transfer of a number from one number system to another

N 5 -2 c | -dj ,, (1)

where N is the initial number (figa);

IJ — current binary and organized code bits, respectively;

bi.Cj - code symbols of the binary and organized representation of a number;

2, dj - bit weight;

kj is the number of binary bits in the jth byte of the code being organized.

At the same time, two bytes (even and odd) are simultaneously allocated, which are formed on a magnetic carrier with different physical characteristics. The even bytes (amplitude attribute) are sent to the input of the first adder 4 via the first group of output buses, the odd bytes are recoded into dj-bit unit positional

codes. This is implemented in hardware by the fact that the odd bytes of the second group of output are sent to the i / o of block 3, and to another group of inputs of block 1 to 3 through switch 5 the varying state of counter 6 is fed. When the state of counter 6, set by counting pulses (period of the following pulses - Ti) from the generator 16 through the control and synchronization unit 15

0 and the counter control unit 7, is compared with the code of the selected j-th group, a comparison signal is generated, which through block 8 determines the start time of the D / A converter 13: TG) SGTI, (2)

5 where Ti is the elementary time sampling required for placing a unit position code on the magnetic carrier (detection window).

Signal level generated by the DAC

0 13, is determined in the adder 12 by the switched switch 10 by the code received from the dial-up field 11 and the code formed as a result of the summation in the adder 4 of the previous value of the adder 4 and

5 of the newly supplied even byte value from the digital switch 2. The previous value of the adder 4 is stored in register 21, the state of which is fed to one input of the adder 4 through the block 22 of keys.

0 The signal level generated by the D / A converter 13 ultimately determines the j-th level of magnetization (fig.Za) in the head 14. The device operates at the recording stage with the arrival of the signal and starting at block 17, which, in turn, activates block 15, at times determined by generator 15. Under control of block 15, the binary counter 6 is reset and triggered through block 7,

0 reset the shift register 9 and 19, clocking blocks 7 and 19 and block 22 keys. In addition, block 7 blocks the restart of block 17 for the entire period of the device operation cycle. The sequence of operations sets 5 with register 18, which defines the number 0) of the received group (cjdj) to the processing by controlling the digital switch 2; using digital switch 20, determines bits of counter 6 involved

0 in the definition of cj; using the switch 20, determines the number of bits of counter 6 participating in this J-QM stage, which are analyzed by block 19 to determine the moment of full recalculation; determines the time intervals Tm and TSJ (by acting on the control unit of the shift register 8), within which the definition of GJ is forbidden (Fig. 3, c).

When playing in the head 23, an emf arises due to the movement of the waveform relative to the head (Fig. 3, d). The reproduction waveform is amplified, then the pulse signals are fed to the input of the discriminator 25, the detector 26 and timer 27. Depending on the polarity of the incoming signal, the discriminator 25 produces a potential characterizing the polarity feature. The moment of occurrence of any signal on the head 23 is recorded by timer 27 in the form of time stamps tj, ... (Fig. 3, d), the binary values of which are fed to the input of the calculator 28. The amplitude detector 26 also in the binary code gives amplitude information to the calculator incoming signal. On the basis of polarity, the meaning of each time stamp is determined. Taking into account the amplitudes of the incoming signals and the time intervals between them, digital information is demodulated. For control, counting the reproduced pulses.

Example. To place the N-bit binary code on magnetic media, a time interval T "is required,

Tk Tm + 2 (Tsj + Ti -dj), (3)

J o where 0,1,2, ... t for the prototype method,

j 0,2,4, ... 2p ... m for the proposed method.

Therefore, for the example shown in FIG. 2, 16-bit binary code can be placed on the time interval Tcr:

Ткр Т „+ Ј (Tsj + Tig d,) Tm - 4 (Tsj +

J 0 + ТИ2 23) Т „+ 4 TSJ + 4 Ти2 23 (4)

For different magnetic recorders, the movement instability of the magnetic carrier has a different character. The common thing is that the instability at large intervals is large, as well as the increase in the detection window T and as the time interval of the code feature increases.

In the prototype, the identification of each byte is relative to the marker, therefore, the detection window is taken with the condition that the identification of the last byte is carried out with the assigned reliability. Consequently, the windows for detecting tee must be taken

so that the accuracy of identification is preserved no less than the specified value on the interval T, which can be determined from the expression (Fig. 3c)

T Tm + 4 (T R / + Ts). (5)

In the proposed method, when sequentially identifying an even byte relative to the previous information packet, it is sufficient to take the time interval T2:

T2 2 (TR + Ts), (6)

As can be seen from relations (5) and (6), in the latter case, the window for detecting Ti can be taken smaller without much damage

for the security of P. identification

Claims (1)

The invention The method of recording and reproducing digital information, which consists in pre-transforming a sequence of digital information into the form of a sequence of information bytes with a given number of bits, dividing this sequence by a marker signal into cyclic sequences, converting information bytes into pulse width signals, recording each pulse width signal simultaneously with a change in the magnetization of a magnetic recording medium in one direction, recording the marker signal by changing the magnetization of the carrier of a different direction, and subsequently reproducing the marker signal and the result of the magnetic recording with counting the number of reproduced pulses when decrypting information bytes, characterized in that. in order to increase the recording-reproduction density of digital information, the sequence of digital information each odd byte is transformed into an even number of consecutive bytes of information, each odd byte is converted into a pulse-width signal, the magnitude of the change in magnetization of the magnetic recording medium is determined by the value of even-byte significance when recording each pulse-width signal, the marker signal is recorded before at the end reproducing the demodulation of digital information is carried out taking into account the amplitude of the reproduced information signals and the time intervals between adjacent reproduced pulses. 1LJLJ rU IIx1 1H N Tw iz. enHdi / godufi onpt AND SP J 832t-I9L . 1001001101011001 . j - YO H .ff.l  H  H- 5 6 7 , f (( T././ p   V - bl /../n A2 T2 V g / 3 3 A T 4/4 FIG. 2 year -Un Tg r2  H  H- 5 6 7   f (( T, gz J b +