SU1243028A1 - Method of quality contrl of magnetic recording of pulse signals - Google Patents

Description

The invention relates to instrument engineering, in particular, to methods for controlling the quality of magnetic recording of pulsed signals of 1-SHFR information on a magnetic recording medium, and can be used in memory devices of electronic computers and in information processing systems.

The purpose of the invention is to improve the accuracy of control.

FIG. 1 shows a block diagram of a device that implements the proposed method in FIG. 2 - signal plots.

The device contains a magnetic head 1 connected to the output of recording unit 2 and to information inputs of elements 3 and 4 of the sampling and storage j whose outputs are connected to the direct and inverse inputs of adder 5, the output connected to comparator 6. The input of recording unit 2, which is input the entire device is also connected to series-connected delay elements 7 and 8, the outputs of which are connected to the control inputs of sample and hold elements 3 and 4, respectively, and the output of delay element 8 is connected to the control house of the comparator 6.

The method is carried out as follows.

The magnetic winding of the head 1 receives the pulse recording signals generated in the recording unit 2 by the information signals input to the device. During the recording pulse, the change in the impedance of the magnetic head is determined by the formation of a magnetic imprint on the carrier, for which, for example, the amplitude of the recording pulse voltage (signal A, Fig 2) at the windings of the magnetic head 1 is measured using elements 3 and 4 samples and storage at two consecutive points in time t; and t, respectively, shifted about the moment of the beginning of the write pulse.

In adder 5, the difference of these voltage amplitudes is determined, which is compared in comparator 6 with a predetermined value (trigger threshold). According to the results of comparison, the quality of magnetic recording and

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if necessary, re-record.

The physical essence of the proposed method is as follows. During the recording of pulsed signals on a magnetic medium, a magnetic footprint is formed, as a result of the interaction with which the impedance of the magnetic head 1 changes, which affects the shape and amplitude of the recording pulse. This effect is minimal in the initial part of the pulse and increases with approximation to the trailing edge of the pulse. The dotted curve (signal B, Fig. 2) corresponds to the signal on the winding of the magnetic head in the case of a poor (weak) print on the magnetic recording medium (for example, due to the deflection of the carrier), the magnitude of the effect on the winding of the magnetic head 1 is less than the required value. Time t and tg. Measuring the amplitude of the voltage on the winding of the magnetic head (and, accordingly, the delay time of delay elements 7 and 8) is chosen so that at the outputs of elements 3 and 4 of the sample and storage, in the absence of recording defects, pulses of approximately equal amplitude are formed. In this case, the output signal of the adder 5, where the signals from elements 3 and 4 of the sample and storage are opposed with the opposite sign w, should not exceed the specified value (comparator trigger threshold 6).

In the case of poor recording (poor quality magnetic print on the carrier), the amplitude of the voltage of the recording pulse at the time of measuring tg. is changed to the value of Uj, and the difference signal (U - Uj.) from the output of the adder 5 will exceed the threshold of the comparator 6, the output signal of which indicates a recording defect. This signal is used by the organization of re-recording on the media. The magnitude of this signal, which characterizes the quality of the magnetic recording, is several times higher than the corresponding value for the known method, and a higher level of the pilot signal makes it possible to increase the accuracy of monitoring the quality of the magnetic recording of the pulse signals.

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Editor V. Petrash

Compiled by A. Lukanin

Tehred M.Morgental Proofreader G. Reshetnik

Zakd; s 3711/52 Circulation 543Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. 4/5

Production and printing company, Uzhgorod, st. Project, 4

Claims (1)

METHOD FOR QUALITY CONTROL OF MAGNETIC RECORDING OF PULSE SIGNALS, according to which the control and organization of re-recording is carried out using a magnetic head that records signals on a magnetic recording medium, characterized in that, in order to increase the accuracy of control, monitoring is carried out during the action of the recording pulse by determining the change the impedance of the magnetic head due to the formation of a magnetic fingerprint on the carrier, while measuring the amplitude of the voltage of the write pulse on the winding of the magnetic head two successive points in time during the action of the write pulse time-shifted relative to the start write pulse, determine the difference between these voltage amplitudes, compare it with a predetermined value, by comparing judged as a recording on _G medium, and if necessary make repeated recording on a magnetic recording medium . FIG. 1