SU771472A1 - Device for orientation and fastening billets for mechanical working - Google Patents

Description

(54) METHOD FOR DETERMINING TRANSVERSE VIBRATIONS OF MOVING MEDIA INFORMATION WHEN READING

one

The invention relates to a measurement technique, in particular to methods of transverse oscillations of an information carrier of an electrostatic recording, and can be used to determine oscillations of a carrier tape during vibration measurements.

A known method for measuring transverse oscillations of a moving information carrier in the form of a magnetic tape consists in that a control electric signal of a constant frequency is recorded on a magnetic link, and the vibrations of the magnetic tape 1 are judged by the degree of distortion of this signal.

The main disadvantage of this method is that it is difficult to determine the direction of transverse vibrations.

The closest to the proposed technical essence is the method of determining the transverse oscillations of a moving carrier when read, which implies that the pulses of a constant frequency generator are fed to a recording magnetic head, with which the control signals are recorded on a magnetic tape. A multi-channel magnetic head is used for reading. Reproducible pulses amplify, convert the frequency of the latter to a digital code in decade counters and register 2J.

When a magnetic tape is moving, due to the dynamic skew and measurement of the voltage plot across the strip widened, the frequency of the repetition of the reproduced pulses through the channels is characterized by the error of the tape movement.

However, this method is difficult to separate.

information on oscillations perpendicular to the carrier plane and in its plane.

The purpose of the invention is the realization of the possibility of determining carrier oscillations in the carrier plane and perpendicular to it.

This is achieved by recording a control signal as n equipotentials in the form of straight lines onto an electrostatic carrier, scanning the carrier across the width of the reading device and judging the amplitude of the 2Q pulses received by the scanning step for oscillations perpendicular to the carrier plane , and the change in the pulse duration during the same time is about oscillations in the carrier plane.

FIG. 1 shows a device for implementing this method; in fig. 2 shows a set of reproducible pulses in a single scanning step; in fig. 3 and 4 show the obtained dependences of the change in the duration and amplitude of the pulses.

The device contains a system of contact electrostatic heads 1 and a reading device in the form of a cathode ray tube 2 (CRT) with a metal screen and mounted perpendicular to electrodes 3 and 4 and a moving information electrostatic carrier 5 on which, using a system of heads 1, a control signal is written as n equipotentials in straight lines 6. The system of heads 1 is connected to a generator 7 of constant voltage. The outputs of the sawtooth generator 8 are connected to the deflecting system of the CRT 2 and the input of the generator 9 of a constant voltage, the output of which is connected to the cathode of the CRT 2. Ground through the resistor 10, the control electrode 4 is connected through the amplifier 11 to the amplitude of the pulse detector 12 and the limiting amplifier 13. The outputs of the latter, respectively, through a PWM signal demodulator 14 and a pulse counter 15 are connected to a recording device 16. The other two outputs of the pulse counter 15 are respectively connected to a recording device. device 17 and through frame counter 18 to recording devices 16 and 17.

The method of measuring the transverse vibrations of the information carrier when reading is carried out as follows.

A system of contact electrostatic heads 1 records on an electrostatic carrier 5 p equipotentials in the form of straight lines 6 of a voltage level, which is set by the generator 7 of a constant voltage.

The recorded control signal is read from the moving carrier 5 by applying to the deflection system of the CRT 2 a sweep signal from the sawtooth generator 8 and to the cathode of the CRT 2 a constant signal level of the constant voltage generator 9. When a beam scanning the CRT 2 hits the carrier 5 on the resistor 10, a voltage drop with zero level occurs. When a CRT beam 2 hits an area of equipotential, an air gap will discharge the CRT screen 2 - carrier 5, current will flow through carrier 5, counter electrode 4, resistor 10, and the last will produce a level A voltage drop depending on the equipotential voltage level. Due to carrier oscillations perpendicular to the carrier plane, the magnitude of the transferred charge will depend on the size of the gap of the carrier screen. Therefore, variable amplitude pulses will be generated on resistor 10, the numbers of which are over

the time of scanning the beam across a moving carrier is n (Fig. 2). The duration of the pulses from the direction of oscillation of the carrier 5. When the directions of oscillations coincide with the direction of the direct

The course of the CRT beam 2 will be longer than the pulse scanned on the carrier 5 with a fixed carrier. Otherwise, the duration of the generated pulse will be less.

The pulses formed on the resistor 10, having passed through the amplifier 11, are fed to the inputs of the pulse amplitude detector 12 and the amplifier-limiter 13 ,. Amplitude-limited pulses from the output of amplifier 13 trigger a pulse counter.

15. When the beam passes through the carrier of the nth pulse, the counter generates a gate-discharge for printing, which is fed to the recording devices 16 and 17. The converted signal from the pulse output

0 of detector 12 (FIG. 4) is fed to a recording device 17, and the PWM converted in demodulator 14 is a signal (FIG. 3) from the output of the latter to a recording device 16, which is also fed from the output of a pulse counter 15

 enabling gate. Both recording devices 17 and 16 from the beam counter π equipotentials are fed to the frame number code, which are printed at the beginning of the sequence from

J n pulses.

This method improves the accuracy of measurements of carrier oscillations along its width when reading, gives a comprehensive picture of carrier oscillations in the area of the read line, and also allows you to divide the absolute

5 information about oscillations in the plane of the carrier and perpendicular to it.

Claims (2)

1. USSR author's certificate number 356447, cl. G 01 B 7/00, 1971. 2. USSR author's certificate No. 293170, cl. G 01 B 7/00, 1969 (prototype). five Ш.2 /  n FIG. needles