RU1795516C - Method of diagnostics of tape drive of apparatuses of magnetic recording - Google Patents

Abstract

Use of the invention: relates to instrumentation, and in particular to methods of test diagnosis of equipment, and can be used in quality control and evaluation of the technical condition of tape drives. SUMMARY OF THE INVENTION: the method consists in reproducing a measurement signalogram of a sinusoidal shape with a reference repetition period of the signal, followed by converting the analog signal into a digital code for the relative time of the signal to go through zero and storing the received code combinations. From the values of the annual combinations, the values of the reproduced periods are calculated with the subsequent determination of the values of the deviations of the periods from their reference value and the values of the deviations are generated as a function of time on the time interval of the implementation of the signalogram. A spectral analysis of the function is carried out to detect the presence of frequencies whose values coincide with the frequencies of rotation of the elements of the tape drive and at which the amplitudes of the periodic components exceed a predetermined allowable level at these frequencies. In the case of detectable frequencies, the presence of defective elements in the tape drive mechanism is fixed, the number of which is equal to the number of detected frequencies. The specific defective elements are determined by the detected frequencies. 4 il, eat C

Description

The invention relates to instrumentation, to methods for test diagnosis of equipment.

A known method for studying oscillations in the driving mechanisms of magnetic recording apparatuses, which realizes the separation of parametric and forced oscillations of the signal carrier by changing the operating mode by switching speeds, with the same test signal acting unchanged.

Closest to the proposed invention in technical essence is a method for identifying the main sources causing an increased level of detonation, including calculating, according to the kinematic diagram of the tape recorder, the values of the rotational frequencies of all elements of the tape drive mechanism (CVL) and fixing them on the frequency axis, feeding to an oscilloscope with an open input the signal from the detonometer output, analysis of the waveform and determination of the frequencies of the periodic components and amplitude relationships between them, comparison of the measurement data with the frequencies E rotating elements and LPM LPM determining the contribution of each element in the overall instability of the tape speed.

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The disadvantage of this method is the low reliability of determining the individual contribution of the CVL elements to the overall instability of the tape speed, due to the biased assessment of the tolerance of the amplitudes of the periodic components of the analyzed process of speed fluctuations, due to its weighing in the frequency domain, taking into account the frequency response of the average auditory perception of a parasitic frequency person modulation of the sound signal.

The aim of the invention is to increase the reliability of the diagnosis of tape mechanisms,

This is achieved by the fact that when playing a measurement signalogram with a reference signal repetition period, the analog signal is converted into a digital code of the relative time of the signal to go through zero, the resulting code combinations are stored and the values of the deviations of the periods from their reference value and the values of the deviations are calculated as a function of time on the time interval of the implementation of the signalogram. After that, a spectral analysis of the deviation function is carried out, in order to detect the presence of frequencies, the values of which coincide with the values of the rotational speeds of the CVL elements and at which the values of the amplitudes of the periodic components exceed the specified level permissible at these frequencies. In the case of detecting frequencies, the presence of defective elements, the number of which is equal to the number of detected frequencies, is recorded in the CVL. Defective elements are determined from the detected frequencies.

Figure 1 shows a block diagram of a device that implements the proposed method; Figures 2-4 are illustrations, for example, where Figure 3 shows the amplitude-frequency spectrum of carrier velocity oscillations caused by elements of a faulty CVL without weighting the spectrum in the frequency domain; Fig. 3 shows the same spectrum in a suspended state; figure 4 - characteristic of the weighing filter.

A device for implementing a method for diagnosing LG (M magnetic recording apparatuses contains a zero-organ 1, the output of which is connected to the input of the control and synchronization circuit 2, the clock output of which is connected to the counter input of the counter (binary) 3, and the gate output of which is connected to the multi-bit inputs circuit, to the information inputs of which the information outputs of the counter 3 are connected, and the outputs are multi-bit

circuits And 4 are connected to the inputs of the buffer register 5, the outputs of which are connected to the interface of the computer 6.

Method using this device

implemented as follows. The measured analog signal reproduced on the magnetic recording apparatus with the diagnosed CVL, recorded with a reference signal repetition period, enters the zero-organ circuit 1, which produces a sign of the signal passing through, zero in the form of an activation signal for the compression and synchronization circuit 2, which upon first activation allows the start of counting to binary counter 3 by starting a continuous supply of clock pulses to its counting inputs, and for all subsequent activations, circuit 2 enables by applying signal Z bearing, mno0 gorazr discharge circuit 4 and realize perezapissosto audio information outputs of the counter 3 to the buffer register 5, from which, during the absence of the signal recorded on the multi-discharge circuit AND 4

5, the digital code is stored in the computer memory 6, where, by means of software, the entered code combinations are extracted from the memory by the values of which the values of the reproduced

0 periods, the values of their deviations from the reference value of the period, which are presented as a function of time, are calculated, a spectral analysis of the function is performed to determine the frequency of the value

5 of which coincide with the values of the rotation frequencies of the CVL elements and at which the values of the amplitudes of the periodic components exceed the specified permissible level, and in the case of detected frequencies, the fact of the presence of defective elements in the CVL, the number of which is equal to the number of detected frequencies and the values detected frequencies are determined defective nodes of the CVL, information about the diagnosis

5 is presented to the operator in a convenient form on the means for displaying information available on a computer.

We take the process of oscillations of the speed of the signal carrier, represented by the instantaneous values of the coefficients of the oscillations of speed A on the time interval of the implementation of the signalogram I and, having performed its spectral analysis with the determination of the amplitudes and frequencies of the periodic components, we obtain the amplitude-frequency spectrum of the process (Fig. 2 )

Now we take the same process of velocity fluctuations and obtain its amplitude-frequency spectrum in a state weighted in the frequency domain (Fig. 3) taking into account the frequency response of the average auditory sound perception by a person (Fig. 4). Taking into account the weighting coefficient Kbi, the amplitude of the 1st periodic component Kgi at frequency fi is redefined to a smaller value:

 Kgi (fi) Ai (fi) Kbi (fi), (1) where 1 1, n:

,:

n is the number of harmonics.

Given a priori frequencies and amplitudes of operational elements of the CVL, we give a comparative analysis of the spectra presented in figure 2 and fig.Z.

From the comparison it is seen that the values of the amplitudes (Fig.2b) due to their weighting in the frequency domain are underestimated in relation to the values of unweighted amplitudes (Fig.2)

by a value proportional to the weighting coefficient at the corresponding frequency (Fig. 4), which led to a diagnostic error in assessing the state of the rotation element 2. If the reliability tending to 1 is taken to be reliability at a frequency of 4 Hz. then with increasing and decreasing frequencies, relative to 4 Hz, the reliability of the assessment of the technical condition of the CVL will decrease, and, at frequencies less than 4 Hz, just characteristic of the rotating elements of the CVL, the reliability decreases more sharply with decreasing frequencies. The proposed method eliminates this drawback and takes into account that the detonation process characterizes only the quality of sound magnetic recording apparatuses.

The invention is a method for diagnosing tape drives of magnetic recording apparatuses, including spectral analysis of an analog signal with the determination of the amplitudes and frequencies of the periodic components to determine the individual contribution of the tape drive elements to the instability of the speed of the signal carrier according to the results of frequency comparison, distinguishing that, in order to increase the reliability of the diagnosis of tape mechanisms, the standard reproduced from the measuring signalogram n signal, it is converted into a digital code of the relative time of signal transition through zero

the received code combinations are stored and the values of the reproduced periods are calculated from their values, the values of the deviations of the periods from their reference value are determined and these values are formed as a function of time, a spectral analysis of the function is carried out and the presence of frequencies is found, the values of which coincide with the value frequencies of rotation of the elements of the tape drive mechanism and at which the values of the amplitudes exceed a predetermined level permissible at these frequencies, in the presence of detected frequencies, the fact of the presence of defective elements is recorded s whose number is equal to the number of established frequency, and the specific defective elements is determined by the value m of established frequency.

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