SU402804A1 - METHOD FOR IDENTIFYING CHANGES - Google Patents

Description

The proposed method relates to the field of motion parameters measurement.

The known methods for determining changes in the speed of movement of a magnetic carrier by recording magnetic marks on it are not accurate enough.

To improve the accuracy of determining changes in the speed of movement of a magnetic carrier, according to the proposed method, labels are applied with the frequency at which the latter overlap, simultaneously measure the mosh needed for recording, and measure its variation with a controlled value.

The drawing shows a schematic diagram of a device implementing this method.

The device consists of a generator of unipolar "pulses 1 with the amplitude necessary to saturate the magnetic carrier 2, and

frequency f - providing overlap

recorded magnetic marks, where V is the speed of the carrier, A is the effective width of the working gap of the head. Unipolar pulses from the generator are fed to the input diagonal of a balanced symmetric bridge 3, assembled from the same resistors 4 and 5, the recording head b, the differential pad tuning coil-7, and the equivalent of the recording head 8 (the equivalent head can be included instead of head 6). The signal containing information on the magnetic carrier speed fluctuations is removed from the output diagonal of the bridge and amplified by the amplifier 9, the high frequency components of the spectrum are filtered out by filter 10 (the frequency of the recorded pulses and its harmonics), and the signal of the magnetic carrier oscillations is fed to the indicator I.

The essence of the operation of the device is as follows.

It is known that in order to magnetize a magnetic carrier, a certain energy is required. If magnetic marks from the pulse generator are recorded, then the magnetization occurs due to the energy of the generator and the tape drive mechanism. When recording on a fixed magnetic carrier, it is magnetized

an element of a magnetic carrier located immediately above the gap of the magnetic head. Energy for magnetization in this case is taken only from the first pulse of the generator.

All subsequent pulses act already on the magnetized carrier and do not give energy to the magnetization. If the magnetic carrier moves with such a speed that the magnetized element during the following period

pulse generator does not have time to out of

the working gap of the magnetic head, then there is an overlap of the recorded magnetic marks. In this case, each pulse of the generator performs work on the magnetization of the carrier. The magnetizing energy consumed from each impulse will depend on how much the magnetized element of the carrier has shifted away from the working gap of the head or on the amount of non-magnetized carrier that has gone over the gap of the head.

Thus, if the speed of pulling the magnetic carrier is not constant, then the power consumed by the pulse generator will also be permanent, which leads to changes in the impedance of the head 6 and the imbalance of the bridge 3, at the output of which a signal appears.

Thus, the signal of the change in the speed of the magnetic carrier is obtained directly in the recording mode.

Subject invention

The method of determining the changes in the speed of movement of a magnetic medium by recording magnetic marks on it, characterized in that, in order to improve accuracy, marks are applied with the frequency at which the latter overlap, simultaneously measure the power required for recording and, according to its variation about the monitored value.

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