SU1203584A1 - Device for measuring transport speed of magnetic tape - Google Patents

Description

The invention relates to instrumentation, in particular, to devices for measuring the speed of movement of a magnetic tape in anaprata magnetic recording-reproduction digital multi-track information, and can be used to assess the quality of the tape mechanism.

The aim of the invention is to increase the resolution and accuracy.

FIG. 1 shows a block diagram of an apparatus for measuring the speed of transporting a magnetic tape; in fig. 2 - signal plots at various points of the device. The device contains a test signal carrier 1 containing a test signal 2, a waiting multivibrator 3, a second driver 4, a counter 5, an indication unit 6 that reads the magnetic head 7, an amplifier 8, the first driver 9 and the element OR 10. The device operates as follows. The magnetic tape 1 with the recorded control signal 2 reproduces the signals of the multichannel reading magnetic head 7. The signals from the outputs of the magnetic head 7 are amplified to the required value by the amplifier 8.

The shaper 9, according to the signals from the inputs of the amplifier 8, at some level forms short pulses on each of its

§

five

about

five

outputs corresponding to the individual channels of the read magnetic head 7 (Fig. 2a, b, c). These pulses are combined on the element OR 10 (Fig. 2d) and are fed to the input of the counter 5. To accurately measure the frequency, the pulse from the first output of the driver (Fig. 2a) starts the waiting multivibrator 3, which produces a pulse of a strictly defined duration (Fig. 2c ). At its duration, counter 5 is opened, on the falling edge of the pulse of multivibrator 3, generator 4 generates a pulse, which records the state of counter 5 in indicator b, in which the velocity of the magnetic tape is calculated using the following form e:

V. Aosposp,

where V.I is the speed of movement of the magnetic tape;

fs is the pulse frequency from the output of the element OR 10;

d is the distance between the individual heads of the multi-track magnetic head unit 7; P is the angle of inclination of the magnetization line of the control signal relative to the direction of movement of the tape.

d

PP

FIG. g

VNIIPI Order 8424/55 Circulation 544 Subsidiary Subsidiary PPP "Patent, Uzhgorod, st. Project, 4

gb

Claims (2)

1. DEVICE FOR MEASURING THE SPEED OF MAGNETIC TAPE TRANSPORTATION, containing a test signal carrier, reading a magnetic head, connected through an amplifier to the first driver, and also a waiting multivibrator, the output of which is connected to the counter control input and the output of the second driver, an indication unit, the information input of which is connected to the counter output, and the manager - to the input of the second shaper, characterized in that, in order to increase the resolution and accuracy, many ANNUAL OR gate, the read magnetic head, the first amplifier and shaper made multichannel, and outputs a first channel generator are connected to the inputs of OR element whose output is connected to the data input of the counter, the output of one of the channels of the first generator is connected to the input of monostable multivibrator. 2. The device according to π. 1, characterized in that the carrier of the test signal contains a sequence of straight oblique lines of magnetization, located at an angle to the direction of its transportation. Fig!