SU670797A1 - Device for measuring deformation of moving magnetic tape - Google Patents

Description

The drawing shows a block diagram of the proposed device.

With magnetic tape 1, two magnetic recording heads 2 and 3 are matched. Winding 4 and 5 through the amplifiers-formers 6 and 7, are connected to the inputs of the installation zero and after the logical elements AND-NOT 8 and 9 - to the inputs of the installation of the single triggers 10 and 11, respectively. The outputs of the triggers 10 and 11 through the logical elements AND-NOT 12 and 13 and the logical element OR 14 are connected to the input of the counter 15, which is connected to the recorder 16. The inverse outputs of the trigger 10 and 11 are cross-connected to the second inputs of the logical elements AND-HE 8 and 9. The output inputs of the reference generator 17 are connected to the second inputs of the logical elements AND –NE 12 and 13. The working gaps 18 and 19 of the magnetic heads 2 and 3 are made under the right side to each other and at an angle of 45 ° to the direction of the tape movement.

The device p & has the following images.

On a moving tape in recording mode, simultaneously and in phase with magnetic heads 2 and 3, two harmonic or pulsed signals are detected.

When moving in the path of the tape mechanism, the magnetic tape I is subjected to perturbations in the form of longitudinal tension forces, which cause its longitudinal deformations. Since two signals are simultaneously recorded in tape 1, longitudinal deformations of tape section A / will cause a temporary discrepancy in the reproduced signals.

Depending on the instantaneous deformations of the tape in the zaggy and replay modes, the signal of the first channel may be ahead or behind the signal of the second channel. Thus, the temporal mismatch of the reproduced signals will be directly proportional to the magnitude of the absolute deformation of the tape segment.

The reduced first pulse, for example, from the output of the amplifier maker 6, through the logical element IS-HE 8, switches the trigger 10 to the one state. The direct output signal of trigger 10 opens the logical element AND-NOT 12 and from the reference generator 17 through the logical elements AND-NOT 12 and the element OR 14, the counter 15 begins to receive pulses with a period of Go. At the same time, the signal of the inverse output of the trigger 10 closes the NAND logic element 9. A pulse coming from the amplifier-mapper 7 switches the trigger 10 to the initial State, thereby closing the NAND logic element 12. The time interval between two pulses my

proportional to tape deformation, will be equal to Ni-TQ, where NI is the number of pulses in the counter 15. After termination of the counting, the numerical value of the measurement result is recorded in the recorder 16. If the pulse appears in the second channel first, then the measurement process will be similar. The signal from the amplifier amplifier output 7 through the logical element AND-NOT 9 switches the trigger 11 to one state, which closes the logical element AND-NOT 8 and opens the logical element AND-NOT 13, through which the pulse begins to flow from the reference generator 17 The pulses pass the logical element OR 14 and are recorded in the counter 15. The second pulse from the amplifier 7, the second pulse, switches the trigger 11 to the zero state and closes the AND-NE logic element 13. The time interval with the inverse sign will be 2 t he pulse counter 15. Thus, the apparatus provides measurement and recording of the data in discrete form, thereby increasing the accuracy of measurement.

Claims (2)

Invention Formula A device for measuring deformations of a moving magnetic tape, comprising two measuring channels, each of which is EXCELED as serially connected magnetic recording-reproducing heads, whose working gaps are made at a right angle to each other and at an angle of 45 ° to the direction of movement of the magnetic tape, and an amplifier -former, and a recorder, characterized in that, with the goal of higher measurement accuracy, it is provided in each channel by a series AND logical NAND, a trigger, a second NAND logic element, common to the channels, successively connected by an OR logic element, a counter connected to the recorder, a reference generator connected in parallel to the inputs of the second logical element AND-NOT of each channel, the output of the amplifier maker is connected to the input of the first logical element AND-NOT of each channel and to the input of setting the zero of the trigger of another channel And the output of the first NAND gate I- NOT one channel is connected to the installation input of the trigger unit of another measurement channel. Sources of information taken into account in the examination I. USSR Copyright Certificate No. 349878, cl. G 01B 7/00, 1970. 2.- USSR Author's Certificate No. 419717, cl. G 01B 7/16, 1972.