SU1304061A1 - Device for generating the coding signals of magnetic tape sections - Google Patents

Abstract

The invention can be used when recording digital information on a magnetic tape in analog magnetic recording devices. The purpose of the invention is to increase the information recording density. The clock pulses from the generator 1 are fed to the input of the distributor 2, with KOK. I E (the second is fed to mixer 4 via keys 3, and from the output of mixer 4 is fed to the input of the code conversion unit 5 returning to zero in the two-phase code. In the driver 6, the edges of the two-phase code pulse are formed. During playback, a signal is received, which allows amplitude extraction of sync pulses of code words, as well as the formation of pulses that determine the source code. The use of code conversion block 5, generator 6 and the formation of new connections allows to exclude the nny oprsds.chn- Tel codeword beginning of informapion hydrochloric sequence and to combine it with the end of the word. 1 yl. ((L with about 4 I i

Description

The invention relates to instrumentation and can be used when recording primarily digital information on a magnetic tape in analog magnetic recording devices (AMR).

The purpose of the invention is to increase the information recording density.

The drawing shows a block diagram of the device.

The device consists of a generator of 1 clock pulses connected to the input of the distributor 2, keys 3, the control inputs of which are connected to the outputs of the code information sensors, and the inputs and outputs are connected respectively to the outputs of the distributor 2 and the inputs of the mixer 4. The output of the mixer 4 is connected to one dou unit 5 code conversion, to another input of which is connected to the output of the generator 1 clock pulses. The output of block 5 is connected to the input of the imager 6, the control input of which is connected to the first output of the distributor 2, and the output to the input of the recording amplifier 7.

The device works as follows.

The clock pulses from oscillator 1 are fed to the input of distributor 2. The latter is a single-ended pulse distributor, made for example on the basis of an annular shift register, in which all the outputs are used. The pulses from the outputs 1, 2 ... t of the distributor 2 are fed to the mixer 4 through the keys 3, controlled from a source of code information (not shown), and from the output of the mixer 4 are fed to the first input of the code conversion unit 5 returning to zero in two phase code. In the former 6, the fronts of the two-phase code pulse sequence are formed in such a way that the edges of the code parcels have the duration TI, and the pulse signal of the last bit of a word or block has the Topsh duration.

During reproduction, a signal is obtained in which the amplitude extraction of the sync pulses of code words (blocks) is possible, since the amplitude of the signal from the front of the pulse of the last bit of each digit (block) of the Copt pre. the amplitudes of the remaining Eb signals as well as the formation of pulses, for example, based on the zero derivative, which determine the source code.

Thus, the use of a code conversion unit, a formation unit, and the introduction of new compounds eliminates the permanent determinant of the start of a code word (block) from the information sequence and combine it with the end of the word (block), which leads to an increase in the density of information recording.

The increase in recording density is due to the elimination of overhead bits intended for synchronization of code words.

five

When a reproduction current pulse is applied to the recording head, the reproduction emf has a bell-shaped form from each differential recording current. The reproduction emf of the reproduction head is proportional to the derivative of the magnetic flux in it, therefore, the differentiating property of the reproduction head manifests itself in the dependence of the amplitude of the bell-shaped reproduction pulse on the rate of change of the magnetic flux, i.e., the duration of the recording current pulse. As the recording current amplitude increases, the reproduction emf amplitude increases to a certain limit, after which the reproduction emf curve begins to decline. Since the magnetization of the tape during recording is proportional to the current Ldp IiA.ni Sin25r / t, therefore, the reproduction emf is proportional to the derivative of this current

0 e f /,) - cos2itf (1)

If the effect of maximum emf is determined by the optimal rate of change of the magnetic flux during recording, then

5 W m (2nf) const (2)

for different frequencies and amplitudes. As the recording current amplitude increases, the AED.TEMF playback increases as the rate of change of the magnetization of the tape increases. However, with the further growth of Ijoa.nt, a decrease in the emf of reproduction is observed.

A two-phase code carrier impulse has a certain rate of rise of the edges of the write current pulses. In order to extract the sync pulses of code words in the corresponding bit of the information code, the rate of rise of the rise edge of the recording current pulse changes, resulting in the possibility of differences in the amplitude of information pulses and pulses used simultaneously to synchronize the code words.

The choice of the angles of inclination of the pulses, corresponding to the information bits and sync marks, is made on the basis of specific implementations of the equipment and the possibility of using the optimum length of the current of the recording current.

The generated two-phase code sequence is fed to the input of the block 6 forming the optimum shape of the differential edge of the pulse signal of the last bit of each word (block) of the code in accordance with the control signal from the first 5 outputs of the distributor 2. When playing, the synch pulses of the beginning of the word (block) can be separated using a two-way comparator with thresholds.

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Claims (1)

Claims of the invention are characterized in that, in order to increase recording density, a device is introduced into it to form a front-end signaling device, a unit for converting the magnetic tape sections, no code, one input of which is connected to the containing clock generator, 5 ° mixer, the other input is with output connected to the input of the distributor, sms-generator of clock pulses, and the output - the key, the keys, the control inputs of which with the input of the front-side imager, Connected to the sensor outputs are the code control input of which is connected to the perinformation, and the inputs and outputs are connected to the output of the distributor, and the output is respectively, with the outputs of the distributor with the input of the recording amplifier, and the inputs of the mixer, and the recording amplifier.