SU830531A1 - Method of recording digital information - Google Patents

Description

. The invention relates to instrumentation, in particular to methods of magnetic recording - reproducing a binary code, and can be used for digital magnetic recording.

A known method of magnetic recording of binary code by the method of return to zero, based on the recording of binary characters by current pulses of different polarity [1}.

But when using this method, the recording density of characters and the accuracy of the information are insufficient

There is also known a method of magnetic recording of binary code by the method of return to zero, based on the recording of binary code symbols by current pulses of different polarity and duration [2].

However, when using this method, it turns out that in the case of parallel input of words, the recording density is insufficient, and self-synchronization of the sequence during playback and the control of missing signals are also impossible.

The purpose of the invention is to increase the density and reliability of the recording. '*

DIGITAL INFORMATION

This goal is achieved by the fact that according to the method of recording digital information based on the recording of bits by current pulses of different polarity and duration, every four bits of the information sequence are recorded with one pulse or pulse, and if the first of the four bits is 1θ 'unit, then the signal is recorded in form of a pulse, the polarity and duration of the first pulse of which corresponds to the second and third bi. there, and the duration of the second pulse of 15th pulse corresponds to the fourth bit, and if the first of the four bits is zero, then the signal is recorded as a pulse, the polarity, duration and sign of the shift relative to 20 but the recording period of which correspond to the second, third and fourth data bits of four bits information sequence.

In FIG. 1 shows a block diagram of a device implementing the method;

in FIG. 2 is a timing chart explaining the method.

The device comprises a recording unit 1, a unit 2 for converting parallel 30 code four bits (tetrads) into serial ones, a unit for generating pulses (bipolar pulses), a unit for generating unipolar pulses, a decoder for 5 bipolar pulses, a decoder for unipolar pulses, a delay unit 7, a unit 8 of the formation of the period, the control unit 9, the node 10 converting serial codebooks into parallel, block 11 playback.

Block 1 is connected by inputs with blocks 3,4 and 9, node 2 is connected by inputs with blocks 5,6 and 9, block 3 is connected by inputs with blocks .9 and 10, output from block 1 / block'4 is connected by inputs with blocks 9 and 10 , the output is with block 1, the decoder 5 is connected by inputs to blocks 7.8 and 9, the output is from node 2, the decoder b is connected by inputs to blocks 7.8 and 9, the output is from the node. 2, node 7 is connected by an input to block 11, outputs are connected to decoders 5 · and 6, node 8 is connected by inputs to blocks 8,9 and 11, outputs from blocks 5,6 and 9, block 9 is connected by inputs to nodes 8 and 10, outputs' with blocks 1-6 and 8.10, node 10 is connected by inputs to block 9, outputs with blocks 3,4 and 9, block 11 is connected by outputs with nodes 7 and 8.

Figure 2, a shows the sequence of characters of the binary code to be written; figure 2, b is a pulse sequence of the recording current corresponding to this code) figure 2, in the playback pulses. ''

The initial sequence goes to node 10, where consecutive codebooks are converted to parallel, and according to the contents of the first 40 bits of the tetrad, the code sequence goes to the bipolar pulse generating unit 3, if the unit is in the first discharge of the tetrad, or to the generating unit 4. 45 unipolar pulses if 'zero. . Moreover, in the block 3 for generating bipolar pulses, the front pulse of the bipolar signal is generated, for example, positive if the second digit of the tetrad is one and negative if zero, while in block 3 for the formation of bipolar pulses the front pulse of the bipolar signal is generated, for example, positive if in the second order of the tetrad, one, and negative if zero. The duration of the front impulse, for example, is increased by an amount which is determined from considerations of the marketability of the reproduced sequence, if the third digit of the notebook’s is one, and left unchanged if zero. The duration of the back impulse is formed, naked 65 example, increased if one in the fourth category, and do not change the duration if zero. In block 4 for generating unipolar pulses, a pulse is generated, for example, of positive polarity, if one in the second discharge of the tetrad, and negative if zero, and the pulse duration is increased, for example, if the third discharge of the tetrad is one, and do not change if zero. In this case, a temporary, for example, positive shift is established relative to the middle of the signal recording period, if one is in the fourth digit of the tetrad, and negative if zero.

When reproducing a sequence of the form of FIG. 2, it enters the reproducing unit 11, and from it is supplied to the delay unit 9 for an integer η of reproduction pulses and to the period generating unit 10 in which the exact delay time is measured and the pulse repetition period ΖΓ is calculated = ~ ·· 3Ρ @. . in p - I, depending on whether the bipolar or unipolar pulse is at the output of the delay unit 7, the pulse arrives either in the decoder of the bipolar pulses or in the decoder of the unipolar pulses, where it is converted into a tetrad of binary symbols. From the decipher ^{1 of} 5 bipolar or b unipolar pulses, the pulse converted into a binary symbol tetrad enters the node 2 for converting parallel codebooks to serial ones, in which parallel codebooks are converted into serial ones and bitwise output to the device.

When using the proposed method, each pulse of the current sequence carries information about four bits, which allows you to record four-bit arrays of binary characters along the shorter length of the medium.

Claims (2)

1. US Patent 3,623,408, cl. 340-347, publ. 13.02.71. 2. USSR author's certificate number 591914, cl. G 11 V 5 / 09.03.09.69 (prototype). BtHlioS T. With headspace21 fiocume / ift