SU913053A1 - Method of measuring moving medium skew - Google Patents

Description

The invention relates to a measuring technique and can be used to determine the motion parameters of a belt signal carrier in vibration measurement laboratories.

There is a method of measuring the skew 5 of a moving medium, which consists in determining the geometric center of the medium, reproduce simultaneously recorded signals from two tracks by the playback unit, _1θ which are then differentiated, and an error signal is generated that determines the media skew [1].

The disadvantage of this method is the difficulty of determining the geometric center of the carrier in the presence of its transverse vibrations.

The closest in technical essence to the invention is a method of measuring the skew of a moving carrier, which consists in recording a control signal _{on a} carrier, reading it with the help of two playback units, generating pulses from the peak of the reproduced signal and judging by the time shift of these pulses. skew [2].

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The disadvantage of this method is the occurrence of errors in transverse vibrations of the carrier.

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

This goal is achieved by recording the control signal as a straight line at an angle of 0 ° ^< 90 ° to the edge of the carrier and scanning synchronously with a constant speed perpendicular to the direction of movement of the carrier.

FIG. I shows a block diagram of a device for measuring the skew of a moving carrier carrying out the proposed method; in fig. 2 - position of the control signal on the carrier.

A device for measuring the bias of a moving carrier, implementing the proposed method, contains two electron-beam tubes (CRT) 1 and 2 with metal fiber screens 3 and 4 and deployment systems 5 and 6 connected to the first output of the control unit 7, and their counter electrodes 8 and 9 are grounded respectively, through the resistors 10 and 11, are connected to the limiting amplifiers 12 and 13, the formers 14 and 15 pulses are connected to

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the second output of the control unit 7 and connected to the separate inputs of the subtraction unit 16, which, in turn, is connected to the recorder 17 via a switch 18 connected to the pulse generator 19.

The method of measuring the skew of a moving carrier is as follows.

The carrier 20 (Fig. 2), to which the control signal 21 is preliminarily in a static state, is applied as a straight line at an angle of 0 ° <</ - 90 ° to the edge of the carrier, is pulled between the metal fiber shields 3 and 4 of CRT 1 and 2 and counter-electrodes 8, 9, made of conductive material and grounded respectively through resistors 10 and 11 on the other hand.

The spin-free electron beams of the CRT 1 and 2 are synchronously scanned perpendicular to the direction of movement of the carrier 20 by the scanning systems 5 and 6, which are controlled by a signal from the first input of the control unit 7. The latter simultaneously starts the shapers of 14 and 15 pulses. At point A (Fig. 2), when the electron beam of the CRT 1 being developed is crossing the control signal 21, the voltage drop generated by the resistor 10 changes sign. Thus, the signal, passing through the amplifier 12, is fed to the input of the pulse shaper 14, the output of which produces a pulse with a duration from the start of the sweep until the intersection of the control signal 21 at point A. CRT 2 of the control signal 21 at point B. These two pulses, the duration of which does not depend on the initial position of the carrier 20, from the outputs of the drivers 14, and

15 pulses are fed to the separate inputs of the subtraction unit 16. At the output of the latter, a differential pulse is produced, the duration of which is proportional to the distance between the marks L and β

5 in the direction perpendicular to the movement of the carrier. This pulse controls the key 18 and transmits to the recorder 17 a certain number of pulses from the generator 19 pulses. The recorder 17 is calibrated so that at its output

¹⁰ to obtain oscillation with respect to the value οί Thus, the amount of carrier skew taking into account the sign is obtained.

The proposed method allows you to eliminate the effect of transverse oscillations of carrying ₁₅ la on the result of measuring the skew.

Claims (1)

Claim A method of measuring the skew of a moving carrier, which consists in recording a control signal on the carrier, reading it using two playback units, generating pulses from the peak of the reproduced signal and judging the misalignment of these pulses using the _25- second time shift, In order to increase the accuracy of measurements, the control signal is recorded as a straight line at an angle of 0 ^{0 <} s <- ^< 90 ⁰ to the edge of the carrier and scanned synchronously with a constant speed perpendicular to the direction of movement of the carrier.