SU1016830A1 - Magnetic recording apparatus parameter non-stability evaluation method - Google Patents

Abstract

A METHOD FOR ESTIMATING THE INSTABILITY OF THE PARAMETERS OF A MAGNETIC RECORDING DEVICE, in which control signals are recorded as three harmonic signals of different frequencies, the highest of which is equal to the upper limit of the frequency range of the magnetic recording apparatus, these signals are reproduced and the amplitude of reproduced signals is measured, and so that, in order to simplify the evaluation process when recording on the carrier, the fourth harmonic signal is additionally recorded, the amplitudes of all signals being equal, and Stacks - with a ratio of 1: 2: 4: 6; during playback, these signals are filtered and their amplitudes are measured at the same time, after which the non-contact between the carrier and the magnetic hchelovki is estimated by the ratio of the amplitudes of the third and fourth signals, the thickness difference of the working layer - by the ratio of the amplitudes the first and second fs. signals, and the instability of the residual magnetization of the working layer (L by the ratio of the amplitudes of the second and fourth signals to the square of the amplitude of the third signal. 10 00 CO / J

Description

This invention relates to instrumentation engineering and is intended for use in the design and research of, magnetic recording equipment.

Methods are known for measuring the instability of individual dynamic parameters of magnetic recording equipment, for example, residual magneti. Based on the processing of special test signals. The disadvantage of these methods is the low measurement accuracy due to the difficulty of eliminating the influence of other dynamic parameters when they are selected during the processing of test signals (non-contact and thickness variation of the working layer).

The closest to the proposed one is a crtoco6 comparative evaluation of the statistical reliability of magnetic recording equipment, based on using control signals in recording in an eed of three harmonic components equal in amplitude to the harmonic components, the highest of which is equal to the upper range limit of the magnetic recording apparatus, reproducing these signals and iz-. . measuring the amplitude of the reproduced signals. This method allows simultaneous assessment of the instability of the main dynamic parameters of the equipment during playback (.contact and thickness variation of the working layer). According to this method, the change in the magnitude of non-contact and thickness of the working layer is determined by the ratio of the amplitudes of the reproduced signals 2.

A disadvantage of the known method is its complexity, since for measuring a parameter it is necessary to eliminate the influence of other parameters.

A: The purpose of the invention is to simplify the method of parameter estimation.

The goal is achieved by the method, in which the control signals are recorded as three harmonic signals of different frequencies, the highest of which is equal to the upper limit of the frequency range of the magnetic recording apparatus, reproduces these signals and measures their amplitudes, additionally records the fourth harmonic the signal, while the amplitude of all signals is chosen equal, and the frequencies - with a ratio of 1: 2: 4: 6; during playback, these signals are filtered and their amplitudes are measured at the same time, after which the signal ku nekontakta between the carrier and the magnetic head is produced t relative amplitudes of the third and fourth signals gage raboch.ego layer - relative amplitudes of the first I.vtorogo signals and instability

residual magnetization of the working layer - according to the product of the amplitudes of the second and fourth: signal to the square of the amplitude of the third signal.

The drawing shows a schematic of an implementation method.

The method is carried out as follows. -

The magnetic carrier of the device under study 1 records a signal consisting of a sum of four harmonic components of equal level with the corresponding frequency ratio from the oscillators 2-5. Recording is performed in linear mode, i.e. with high frequency bias or: direct current bias.

The recorded signal is reproduced, its harmonic components are separated using filters 6-9, and their amplitude values are synchronously measured using amplitude detectors 10-13.

The calculation of the desired parameters and their instability, as well as the mutual spectral processing of the obtained data can be performed using specialized devices 14 or computers.

Multichannel analog-to-digital converters 15 are used to input the signal into the computer. With sufficient speed, the computer can also be assigned the functions of frequency filtering and amplitude detection, thereby simplifying the measurement circuit.

It is known that the output voltage of an induction reproduction head is expressed as.

((I) oc (, e),

where Uactszs Jc is a deterministic component;

Up (52, d), (I, E) K (52,) Kd (I, B) is the random component of the reproduced signal;

2Mf Ca-WVj.bfSZ Г - wave density

3 records (f- frequency

signal); .

e - the coordinate of the carrier (Vj - write speed)

sinjrzda

S (i sgz) th

- slit function}

.

e) residual magnetization of the carrier; K (SZ, t) Kd (S, t) are the wave coefficients of contact and layer losses, respectively.

If you choose a random component model

; ys ,, (e; (g) -)

u (Q, e; "e

As

(1) At the same time, Sn is approximated by a function, where X сРз () is the equivalent recording area. To determine the desired non-contact aa (E), the multiplicity d (E), and the C E, you need to solve an equation system of the type (1) for the three components x and f) However, you can more accurately use the relative method, excluding the constants C, which requires an increase in the number of constants control signal to four. Denote the ratio of these v frequency components k.- Grouping the deterministic and random terms, we obtain the calculated ratio in the form S nmfiZtA (slnSZc g Am / -nSiclte) 51ppa Gr (e) - (nm} 52 3 (ej (1st)) sin (ej and tamplitude values of the spectral components gp t. An exact solution of a system of transcendental-type equations of type (2) can be obtained on a computer using an interaction or variational method, and the accuracy of the solution is improved if all the terms of the equation within the selected signal model are taken into account when taking into account the parameters of the recording process. The use of four frequency control signal allows not only to additionally evaluate the main dynamic parameter of the recording process, the change in the residual magnetization, but also improve the measurement accuracy of the playback parameters compared to the prototype, which assumes the residual magnetization is constant. F J fo f f It 4 : 4: 6 allows us to obtain a simpler approximate solution and d. Lg) n "-" - 1., H. , /, - ъ ъ ъ, (е;, (е U. and и are the amplitude values of the signals at the frequencies /, i, 7. e f, respectively. Hence, the full understanding of the dynamic parameters "He; iosefi2T, - d (e) Acn, (e) "are associated with the corresponding ratios of the amplitude values of the reproduced signals. Simultaneous determination of all basic dynamic parameters using the same type of methods and instrumentation simplifies the measurement process, and determining their effect on the output signal components experiment, simplifies the evaluation process.

Claims (1)

METHOD FOR ASSESSING THE INSTABILITY OF MAGNETIC RECORDING PARAMETERS, in which control signals are recorded in the form of three harmonic signals of different frequencies, the highest of which is chosen equal to the upper boundary of the frequency range of the magnetic recording apparatus, these signals are reproduced, and the amplitude of the reproduced signals is measured, such as The reason is that, in order to simplify the estimation process when recording on a medium, the fourth harmonic signal is additionally recorded, while the amplitudes of all signals are chosen equal, and the frequency oty - with a ratio of 112: 4: 6, during playback, these signals are filtered and their amplitudes are measured at the same time, after which the non-contact between the carrier and the magnetic head is estimated with respect to the amplitudes of the third and fourth signals, the thickness of the working layer is compared with the amplitudes of the first and second signals , and the instability of the residual magnetization of the working layer with respect to the product of the amplitudes f of the second and fourth signals to * the square of the amplitude of the third signal. (to the instrument to use the following records.