SU773712A1 - Device for determining the moment of change of magnetic tape movement direction - Google Patents

Description

The invention relates to instrumentation, in particular, to a technique of magnetic recording, and can be used in control systems of magnetic recording equipment. A device is known for determining the moment of change in the direction of the movement of a magnetic tape in a tape recorder mechanism, which holds the receiving and feeding side nodes, on which the magnet is located on the tape, the driving unit and the braking device with electrical contacts connected to the direction indicator l. The device is simple in construction. The disadvantages of this device are low reliability and low technical resource of the mechanical parts of the assembly involved in determining the moment of change in the direction of movement of the magnetic tape. The closest to the invention according to the technical essence is a device for determining the moment and changing the direction of movement of a magnetic tape in a tape recorder mechanism, containing interfaced with moving magnetic flax. This sensor has two photodetectors connected to the respective imaging devices, the first of which is connected through the first matching element connected in series and the trigger to the indicator, as well as a separate second matching element. The device is reliable in operation and makes it easy to receive signals about a change in the direction of movement of the tape in mechanism 21. The disadvantage of this device is that it flies around with a significant error in determining the moment of changing the direction of movement of the magnetic tape. The error here is that after the moment of changing the direction of movement of the magnetic tape a certain time interval passes before the signal at the output of the device corresponds to the new direction of movement of the tape. The time interval is determined by the speed of movement of the magnetic tape and the length of the cut pieces, which passes over the surface of the watering measuring roller when the tape moves during this time interval in a new, reverse direction from the moment the direction changes.

movement until the device triggers.

The aim of the invention is to improve the accuracy of determining the moment of change in the direction of movement of the magnetic tape.

The goal is achieved by the fact that a device containing a sensor coupled with a moving magnetic tape with two photodetectors connected to the corresponding formers, the first of which is connected through the first matching element in series and the trigger to the indicator, as well as a separate second matching element are introduced two flip-flops and an additional pulse generator and a photodetector mounted in the sensor connected in series with the primary inputs; the first input is first The matching element is connected to the first input of the second matching element, the output of which is connected to the second input of the trigger, and the output of the second driver is connected to the second inputs of additional triggers, the outputs of which are separately connected to the second inputs of the corresponding matching elements.

The drawing shows a block diagram of the proposed device.

The device contains a tape motion sensor 2 coupled with a moving magnetic tape 1, the outputs 3, 4 and 5 of which are connected to the imaging unit b, 7 and 8 pulses. The output of the first driver 6 is associated with the first input of the additional trigger 9 and with the second input of the additional trigger 10. The output of the second driver 8 is connected with the first input of the trigger 10 and the second input of the trigger 9, the outputs of the trigger 9 and 10 are connected to the first inputs of the elements 11 and 12 matches, the outputs of which are connected to the inputs of the trigger 13. The outputs of the trigger 13 are associated with indicators 14 and 15 of the direction of movement of the magnetic tape. Tires 16 and 17 are output and are designed to use signals about the change of direction of the tape. a tape transport system control zhnym mechanism control system and system for measuring the amount of 1 agnitnoy tape in a magnetic recording apparatus.

The motion sensor 2 consists of a measuring bypass roller 18 fixed on one axis and a code disk 19 with holes 20, 21 22 evenly spaced along its edge (the other holes are not numbered). The light receivers 23, 24 and 25 are located in a certain way relative to the holes of the disk.

For example, the distances between the receivers 23 and 24, 24 and 25 are equal to each other and are proportional to the segment. Circumference of the bypass measuring roller 2

Circular distance between the first and second photodetectors C and between the second and third. are in the following relationship: t,

1,25th

The device works as follows.

This order of placement of the light receivers 23, 24 and 25 ensures the sequential and alternate generation of their signals. For example, when the code disk 19 rotates in direction A, as shown by arrows in the drawing, a pulse appears first at the output of shaper 6, then a pulse appears at the output of shaper 7 and the last appears a pulse at the exit of shaper 8. Let the code disk rotates in the direction A. The output pulse of the imager b overturns the trigger 9, and the trigger 10 is set into the initial state. The pulse then generated at the output of the driver 7 passes through the coincidence element 11, since at its other input there is a resolving potential of the trigger 9. This pulse emerges at the first input of the trigger 13. The trigger 13 is set to the state that corresponds to the movement of the magnetic tape 1 in the direction A An indicator 15 is turned on, and a Motion command signal appears on the output bus 17, A.

Further, the output pulse of the driver 8 overturns the trigger 10, and the trigger 9 returns to the initial state. But with further rotation of the disk 19 in the direction A, the next output impulse of the driver 6 again begins the considered cycle of operation. Thus, the confirmation of the signal-command Movement A already present at the device output occurs. After changing the direction of movement of the magnetic tape 1 and, consequently, the direction of rotation of the disk 19, the output pulse of the former 7 passes through the coincidence element 12 to the second trigger input 13 The trigger 13 is set to a state that corresponds to the movement of the magnetic tape in the direction B. This turns on the indicator 14, and on the output bus 16 sets the signal command Motion B.

Claims (1)

Invention Formula Device for determining the moment of change of direction of movement