SU860126A1 - Method of determination of information tape medium speed non-uniformity - Google Patents

Description

I

The invention of fire detection in automation and measurement technology, in particular, in methods for measuring the motion parameters of electrostatic recording media, can be used to control the quality of the performance of precision media scan nodes.

Various methods are known for measuring the uneven speed of movement of the tape carrier on which the operation of the devices is based. The essence of these methods consists in recording a pulsed test signal on a carrier, reproducing it, subtracting from a reproduced reference signal, the result of which determines the unevenness of the speed p. 2 and C3.

The disadvantage of these methods is that the accuracy of the measurement is influenced by the deformation of the carrier in reproduction of the head. The closest in technical essence to the present invention is a method based on recording the test signal on the carrier, reading it and converting it into an electrical control signal. In this method, a test of a test signal is recorded on the carrier, it is read (reproduced), the phase of the reproduced signal is converted, and the phase difference between the reproduced and reference signals is determined, which determines the uneven speed of the carrier 4.

The disadvantage of the known method is that the accuracy of the measurement is influenced by fluctuations of the longitudinal tension (deformation of the carrier) in the region of the slits of the magnetic head, as well as the misalignment of the carrier.

The purpose of the acquisition is to improve measurement accuracy.

Claims (4)

This goal is achieved by the fact that, in a known method, based on aa test on the test signal nosgel, if you convert it into an electric control signal, the test signal is recorded on the carrier as a rectangular mark at an angle to the direction of movement of the carrier, and tip ;: reading a rectangular mark is scanned with a beam along lines parallel to the smaller sides of the mark; they generate pulses at the moments of the intersection of a large rectangular mark by a beam; they fix two cscr signals, reverse temporal and Intervals between pulses with two consecutive scans of the beam and the difference in the two control signals are indicative of uneven speed of movement of the carrier beam. The drawing shows a block diagram of a device that implements the proposed method. The device contains a cathode-ray tube 1 (CRT) with a metal fiber screen (MVE), installed perpendicular to the rigidly fixed center electrode 2, on which the moving carrier 3 slides, on the test signal in the form of a geometric figure-mark 4, with its smaller sides pointing towards the direction of movement carrier at an angle. The longitudinal axis of the CRT 1 screen is perpendicular to the large sides of a rectangular mark 4. A sawtooth current generator 5 is connected to a CRT deflection system 1, the cathode of which is connected to the output of a high voltage source 6. The counter electrode 2 is grounded through a resistor 7 and through an amplifier 8 is connected to the counting input of the trigger 9. The output of the latter is connected through a series-connected converter 1O of its interval to the code and the operation unit 11 is connected to the input of the recorder 12. The proposed method is carried out as follows. The carrier 3 is set in motion. As a result of supplying a sawtooth current from the output of the generator 5 and a constant voltage to the cathode from the source B to the deflecting system of the CRT 1, the beam of the CRT 1 scans through the electrodes of the metal fiber screen. The potential of the latter reaches the voltage of the breakdown, which results in the transfer to the carrier 3 of the electrostatic charge. It is in the form of a current running along the circuit; carrier 3- counter electrode 2-resistor 7-body (not shown). At the moments when the beam intersects the large sides of the label 4 on resistor 7, short pulses are generated, and the amplitude of the horns depends on the potential difference of the electrodes of the CRT screen 1 and the residual loss of the perimeter of the rectangle 4, two pulses are formed on the CRT 1 beam on resistor 7 After amplification in the amplifier 8, they arrive at the counting input of the trigger 9. Moreover, the first of them cocks the trigger 9 into the single state, and the second sets it to the initial state. A test signal in the form of a geometric figure — rectangular mark 4 is applied to a fixed carrier 3, which is in a pretensioned state to such an extent that it stretches as it moves. In this case, the length of the smaller cap of tag 4 is equal to fb. With a fixed carrier 3, the duration of the pulse, which is of phase at the output of the flip-flop 9, is equal to, where N / is the scanning speed of the beam on the metal-fiber screen. When the carrier 3 is moving, the relative scan rate of the USGGI beam on the carrier is determined by the formula GV - the projection of the speed of movement of the carrier 3 to a smaller storcia V -V nv n therefore the pulse duration at the output of the trigger 9 in this case is determined by the following rotation C. ; (3) where C is the length of the segment along which the beam is scanned, when the carrier is moving, between two large rectangular marks. The difference between C and b is C-L VH, t-° GOS &. From the Uram (4), I define C + Uts ir-cosia. Substituting (5) into (3), we obtain t-H-t -oos0 From equation (6), we define the expression for TV. p TV.-b-.CV v t COS t lIpH the first beam scanning on the CRT screen 1 at the output of the trigger 9 forms an imp; -fire with duration c, and at the second and /. The speeds of movement of carrier 3 at these moments are respectively 1 (l - COS | b Il G-, / (v-)) The unevenness of the speed of two carriers of the 1st carrier is determined by the difference in the impressions (8) and (9) c r ,, jOO Sp. Ua, / The pulses from the output of trigger 9 are fed to the input of converter Yu, where their durations are converted into code.The resulting codes are sent to the input of the OHHCjro operation of block 11, which performs the following operations: calculates the pulse values of the last pulses obtained successive scans of the beam on the MPE, and multiply this difference to a constant multiplier is 05. The result obtained is viewed by the recorder 12 on a graph. It is judged on the magnitude of the non-uniformity of the velocity of the carrier. The measurement result is not affected by the deformation of the carrier, which increases the accuracy of the measurement. They provide an almost instantaneous value of 8 6 unevenness of the speed of movement of the carrier. In addition, the proposed method has a simplicity, a small amount of hardware implementation and high reliability. The method of determining the uneven speed of movement of the tape information carrier, based on recording on H (x: test test signal, reading it and converting it into an electrical control signal, characterized in that, in order to track the accuracy of the method, the test signal is recorded on the carrier in louse rectangular mark at an angle to the direction of movement of the carrier, and when mixing the rectangular mark is scanned with a beam along lines parallel to the smaller sides of the mark, pulses are generated at the moments of intersection the beam of large sides of the rectangular mark fixes two x control signals, back tpcdcic to the time intervals between pulses with two successive scans of the beam, and by the difference of the two control signals, the carrier bears on the motion velocity. during examination 1. USSR author's certificate No. 461444, class G 11 B 15/46, 1972. 2. USSR author's certificate number 477344, cd. G 01 P 3/54, 1974. 3. USSR author's certificate No. 532О5О, cl. G O1 P 3/54, 1975. 4. USSR author's certificate N 326513, cl. G O1 P 3/56 (prototype).