SU1075302A1 - Method of recording and reproducing service synchronizing signals on magnetic medium - Google Patents

Abstract

METHOD FOR RECORDING AND REPRODUCTION OF SYNCHRONIZATION SYNCHRONIZATION SIGNAL SERVICE SERVERS TO A MAGNETIC MEDIA based on recording signals of binary code units together with service signals of a sequence of zeros, which determine the number of next zeros and when the specified value is exceeded, write to the magnetic carrier, the number of the zeroes can be used to create a magnetic media tool that can be used to create a magnetic medium. after registering this series of the following signal samples of zeros, characterized in that, in order to increase the recording density, the service signal is recorded In this case, during the reproduction, service signals are implanted by determining the time intervals between the end and the beginning of the two-threshold limitation (the generation of adjacent signal-different repulses of reproduction of the service signal. 1

Description

This invention relates to instrumentation and can be used in magnetic recording apparatus.

There is a known method of recording synchronization signals in a digital magnetic recording channel (CML), using which code units record differences in the magnetization reversal current at the boundaries of symbol intervals, and code zeros record them as utility current drops in the middle of symbol intervals 1. At the same time, as a result of recording service signals in In the middle of symbolic, delay modulation intervals 7 / detection window (TD) during playback of recorded signals is reduced to a value of 0.5 TK where Tj. - symbol interval (period of code symbols, which reduces the density of this method, the reliability of the reproduced signals is not high enough, which is associated with a low reliability of their identification in case of a malfunction due to parasitic amplitude modulation (increased danger of reverse operation).

There is also known a method of recording and reproducing synchronization signals in pairs of half-drops of the total current of the remagnetization of the carrier at the boundaries of symbol intervals 2.

The disadvantage of this method is the great mutual influence of the reproduced signals, which leads to a decrease in the accuracy of determining the moments of their recovery, as well as the dependence of the shape of the reproduced service signals on the change of the recording mode.

By its technical essence, the closest to the proposed technical solution is the way of recording synchronization signals, the implementation of which determines the number of signals, zeros, following each other, and if it is greater than or equal to some number or n used by the channel, the service signal in each series of C21 zeros is written to the magnetic carrier. This method provides greater reliability in the allocation of clock signals, since there is no danger of reverse operation. However, the service sync signals during its implementation are recorded on the carrier at intervals of 1.5 Tj, which necessitates determining the duration of the reproduced signals with an accuracy of + 0, 25 TC. Due to this, with a high density of recording of code signals on the carrier due to the mutual influence and the influence of other parasitic factors of the CMZ channel,

for example, noise, the reliability of the sync overhead signal is reduced, and, therefore, the recording density is tolerated.

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

This goal is achieved due to the fact that in the method of recording and reproducing sync overhead signals on magnetic media, based on the recording of signals of binary code units, together with overhead signals of a sequence of zeros, which determine the number of next consecutive signals of zeros and when it exceeds the specified value a service signal is recorded on a magnetic carrier in the symbol interval after the registration of this series of the following sequences of zero signals; the service signal is recorded even and greater than two numbers The magnetization fluctuations are within the symbol interval, and during reproduction, the tracking signals are distinguished by determining the time intervals between the end and the beginning of the reproduction of the service signal formed during the two threshold limits of the different polarity of reproduction.

With this method of recording and reproducing service sync signals, the permissible marginal error of determining the position of the sync signals increases to +0.5 T (when using the recording method without returning to zero), which at large recording densities causes a greater reliability than in the known method (prototype) sync selection.

In addition, the use of the proposed method allows one to record the same type and, therefore, use the same type recording and playback devices, several types of service sync signals, for example, four-time magnetization differential signals, and block synchronization signals (block markers) with six service magnetization differences. During reproduction, it is easy to distinguish these service signals from each other by the time interval between the end and the beginning of adjacent repetitive polarized pulses.

FIG. 1 shows one of the possible structural diagrams of an apparatus for carrying out the proposed method. FIG. 2 shows plots of electrical signals explaining the operation of this device.

Input 1 for signals of units of code is connected to the input of register 2, shifted by two clock intervals. the synchronization input of which is connected to the input 3 for the synchronization signals, and to the input of the element 4, the other input of which is connected to the input 5 for the marker signals of the beginning of the block of binary symbols, and the output to the input of the zero setting of the counter 6 for five, the first input connected to input 7 for signals of code zeros, and the second intended to advance the counting - to the output of this counter, which is connected to the input of the block 8 forming an even, but more than two, number of service pulses, the output connected to one input of the element OR 9, the other the entrance of which connect not with the output of the register 2, and the output through the amplifier 10 recording to the head 11 of the recording. The playback head 12 is connected via a correction amplifier 13 to the first 14 and second 15 shapes of square pulses from positive and negative reproducible signals, which are output connected to the inputs of block 16 for generating and summing pulsed signals from the edges of the output rectangular coal signals of drivers 14 and 15. The output unit 16 is connected to one input of the element I 17, and to its other input through serially connected drivers 18 and 19 of gating pulses. The output of element 17 is the output 20 of the device. Signals of units of code (plots of FIG. 2) are input to the device, which are shifted at the output of register 2 by two clock intervals (plots of FIG. 2) using clock signals (not shown in plots of FIG. 2) input 3. Signals code zeros (plots S (Fig. 2) come from input 7 to input b of counter b, which is set to the zero state by the unit signals from input 1 and the marker sigmals of the beginning of the binary characters block from input 5 inputted to the input of setting the counter b to zero through the element And 4. Counter b generates an output signal after the arrival at its input, for example, five first signals of zeros and then, by advancing the count to two, carried out using feedback from the output of the counter to its input, for example, every three zeros of the zeros (plot g, fig. 2) The output pulses of counter 6 arrive at the input of a shaper of even more than two, the number of pulses with a small, compared to the clock interval of the code symbols, the repetition period (plots 3 of Fig. 2). These pulses and pulses of unit signals from the register 2 output (plots e FIG. 2 / via element 9 OR arrive at the counting input of the trigger 10 and then onto the recordable head 11 (diagrams and Fig. 2 I. During playback, the signals from the playback head 12 are amplified and corrected in the amplifier 13 (diagrams 3 of Fig. 2) and arrive at formers 14 and 15 rectangular pulses from positive and negative reproducible signals. Signals from the output of these formers (Pick plots of Fig. 2) are supplied to two inputs of block 16, in which the pulse signals from the fronts of output pins are formed and summed and summed.forcing pulses of formers 14 and 15 (diagrams L - Fig. 21. The output signals of block 16 are fed to one input of element 17 directly, as well as to another input of element 17 through formers 18 and 19 of strobe pulses (diagrams of min. Fig. 2) .. Thanks This output 20 of the device that implements the proposed method is distinguished from service synchromeshs (plots 6, Fig. 2). The proposed method of recording and reproducing synchronization service signals can significantly increase the reliability of the synchronization system in the case of using sinhroniziruyuschihs codes. As is known, the highest limiting recording density can be achieved by using the recording method without returning to zero (BVNM). However, a significant disadvantage of this method is the lack of synchronization signals when a long run of zeros arrives at the recording (BBHM — the method does not have the self-synchronization property). A higher density of the binary code recording in comparison with the BVNM method can be obtained by using the pulse-potential (PI) recording method, but it also does not oblige the self-synchronization property, since when it is implemented, the zeros of the code are not recorded on the magnetic carrier. Therefore, potentially the highest recording density when using BVNM and PI recording methods in the presence of a long series of zeros in real channels PMR is not achieved. To eliminate this drawback, transcoding primes are used, which leads to an increase in the speed of the code signals (redundancy 1 received for recording, and as a result, a reduction of the detection window during playback. All this reduces the recording density of information signals. In addition to transcoding,

To eliminate the lack of BVNM and IP methods (lack of synchronization signals when recording long runs of zeros /, methods of recording the zeros of the code by synchronization overhead signals described above are used. The proposed technical solution improves the reliability and accuracy of the recovery of synchronization overhead signals

000000

when playing due to the exclusion of the institute of pauses in the reproduced signals, to eliminate the lack of BVNM and PI methods of recording / absence of synchronization signals in the pauses) and, as a result, increase the density of the binary code in real PMZ channels, possibly (20-30% with a high fidelity of the reproduced signals.

Claims (1)

; METHOD FOR RECORDING AND PLAYING SERVICE SIGNALS OF SYNCHRONIZATION ON A MAGNETIC CARRIER, based on recording signals of binary code units together with service signals of a sequence of zeros, in which the number of successive signals of zeros is determined and, when it exceeds a specified value, the service signal is recorded on a magnetic carrier in the symbol of this series of signals of zeros following in a row, - characterized in that, in order to increase the recording density, the service signal is recorded even and the largest two number of magnetization drops within the symbol interval, and during reproduction, service signals are distinguished by determining the time intervals between the end and the beginning of adjacent unipolar impulses of reproduction of the service signal formed by two-threshold limitation.