SU684608A1 - Device for measuring magnetic carrier movement speed - Google Patents

Description

(54) DEVICE FOR MEASURING THE VELOCITY OF MOTION OF THE MAGNETIC MEDIA

one

The device relates to a precise magnetic recording technique, namely, devices for measuring the speed of movement of a magnetic carrier, and can be widely used to test the mechanisms for transporting a magnetic carrier.

A device for measuring the speed of movement of a magnetic carrier is known, comprising sensors interfacing with carrier 1.

However, this device has insufficient measurement accuracy due to fluctuations in the speed of movement of the carrier during recording.

It is also known a device comprising a magnetic head with two working gaps, connected through a switching node to a recording unit made in the form of a pulse generator and a divider, and a reproducing unit, a control unit, a recording unit and a shaping unit consisting of a comparator, a zero-organ, delay circuits, a dumper, two triggers, an OR circuit, four AND 2 circuits.

The disadvantage of the device is the lack of accuracy of the velocity measurement.

The aim of the invention is to increase the reliability of the velocity measurement.

The aim is achieved by the fact that in the proposed device a delay circuit is made with two outputs, the second output of the delay circuit being connected to another input of the third AND circuit, the output of which is connected to the register unit, the comparator output is connected to. one input of the inhibit circuit, the second input of which is connected to the output of the zero-organ, and the output to the counting input of the second trigger, the output of which is connected to the input of the first trigger and to the third input of the first circuit AND, and the output of the second circuit is connected to the registration unit.

FIG. 1 shows a block diagram of the device; in fig. 2 - the cyclogram of his work.

The block diagram of the proposed device for measuring the speed of movement of the magnetic drive contains a magnetic head 1 with two working gaps, connected via a switch 2 to a recording unit 3 consisting of frequency divider 4 and generator 5, n playing unit 6, control unit 7, unit

register 8, a formation unit 9, which consists of a first AND 10 circuit, a comparator 11, a delay circuit 12, a reset signal generating circuit 13, a first trigger 14, a second And 15 circuit, a zero-body 16, a prohibition circuit 17, a second trigger 18, and the third circuit And 19, and magnetic carrier 20.

The device works as follows. In the initial state, the frequency at the output of the first circuit AND 10 is absent, since the circuit is closed at the first input connected to the control unit. The registration block does not work.

By. The signal carrier 20 starts to be pulled from the control unit 7, and a three-pulse burst appears at the exit of the magnetic head 1. The average pulse in amplitude amplitude of the packet. This burst of pulses is obtained by recording the pulses with the same double-slot head. The pulses amplified by the playback unit 6 are fed to the input of the comparator 11 and the zero-body 16. The output of the comparator 11, adjusted accordingly, passes only the average maximum amplitude pulse. The entire pulse train passes to the output of the zero-organ 16, the indicated pulses from the output of the zero-organ 16 and the comparator 11 are fed to the inputs of the prohibition circuit 17.

Two extreme pulses are passed through inhibit circuit 17, since the signal from the output of comparator 11 is prohibiting for the average pulse coinciding with it. These pulses are sent to the counting input of the second trigger 18 and from its output to the single input of the first trigger 14. Possible condition of the triggers at this stage of operation of the former is impractical because the first AND 10 circuit is closed by a signal from the control unit 7 and the counting pulses into the block Registration 8 is not received.

The signal from the output of the comparator 11, delayed by the delay circuit 12 for a time slightly shorter than the period of the pulse bursts, and amplified by the formation of the reset signal 13, embraces the recording unit 8, the first 14 and the second 18 flip-flops, which inhibit potentials from the single outputs. all the AND schemes, k, issues a readiness sign to the control unit 7. The last one, when it is ready, from the generation unit 9 opens the AND 10 scheme at the first input. Thus, the device is set to its original position.

Upon receipt of the next burst of pulses at the input of the imager 9, the operation of the comparator 11, null-irgam 16, delay circuits 2, circuits f) p of the cnna / and reset 13 circuits

four

ban is similar to that described. The first impulse coming from the output of the prohibition circuit 17 to the input of the second trigger 18 sets it in a single position, and thereby opens the AND circuits through the inputs connected to the single output of the second trigger. Since the first circuit AND 10 at the input connected to the mapping unit 7 is open when the device is set to its original position, pulses from the generator of the recording unit begin to flow to the input of the recording unit 8. Upon the arrival of the second pulse at the counting input of the second flip-flop 18, the latter is set to the zero position, transferring the first flip-flop 14 to the single state and closing all the circuits I with the low potential of the single output I. The flow of counting pulses to the recording unit 8 stops. The signal from the second output of the delay circuit 12, a somewhat leading signal from the first output of this circuit, does not pass to the registration unit 8, since the third And 19 circuit is closed at the input connected to the second trigger 18. The signal from the first output of the delay circuit 12 , delayed relative to the mid-day impulse of the burst by a time a little less than the period of the pulse burst following, zeroing the triggers, the registration unit and confirming readiness to the control unit, i.e. reset the device. Thus, the measurement cycle of the movement of the signal carrier is completed. In the process of the described cycle, the pulses from the generator of the recording block, the number of which depended on the distance between the extreme pulses of the stack, i.e. from the speed of movement of the signal carrier. Upon the arrival of the indicated bursts of pulses, the measurement cycle is repeated.

If a false pulse arrives at the input of the imaging unit 9, the operation of the device differs from that described by the fact that, due to the excess impulse, the counting input of the second trigger 18 passes three impulses. After the arrival of the third pulse, the first 14 and second 18 triggers will be in a single state, with the second scheme And .15 being opened on both inputs, and a signal will be sent to the registration unit that indicates the presence of a false signal in the loop in this cycle. . Before the next batch of pulses arrives, the reset signal will set the device to its initial state.

In the event of the disappearance of one of the burst pulses, the operation of the device differs from that described by the fact that only one pulse will pass to the counting input of the second trigger 18, and the trigger will be in the unit until the reset signal arrives. As already indicated and as it follows from the sequence diagram of the operation of the device, before generating a reset signal from the second output of the delay circuit 12, a signal arrives at the second input of the third circuit. This signal, having passed the AND circuit, enters the registration unit as a sign of the measurement of one of the burst pulses in this cycle. Before the next batch of pulses arrives, the reset signal will set the device to its initial state. From the description of the operation of the device, it follows that the measurement of the speed of the signal carrier is carried out in cycles, at the beginning of each cycle the device is reset. If a spurious impulse or loss of impulse arrives at the device input, the device generates and outputs the corresponding sign to the registration unit. The invention The device for measuring the speed of movement of a magnetic carrier, containing a magnetic head with two working gaps, is connected through a switch with a recording unit, and through a playback unit - with a shaping unit, made in the form of a comparator, connected through a delay circuit, made in the form of a multivibrator, and form

t I is a reset signal with inputs of the first and second triggers, the zero-organ, the first And circuit, the first input of which is connected to the control unit, the second one with the recording unit, and the output is connected to the registration unit of the second And circuit, one input of which is connected with the output of the first trigger, and the other with the output of the second trigger, and the third And circuit, one input of which is connected with the output of the second trigger, and the inhibit circuit, characterized in that, in order to increase the accuracy of the velocity measurement, the delay circuit is made with two outputs , with the second output circuits the delay is connected to another input of the third And circuit, the output of which is connected to the registration unit, the output of the comparator is connected to one input of the inhibit circuit, the second input of which is connected to the output of the zero-organ, the output to the counting input of the second trigger, the output of which is connected to the input of the first trigger and with the third input of the first circuit And, and the output of the second circuit And connected to the registration unit. Sources of information taken into account during the examination 1. USSR author's certificate No. 461444, cl. G And B 15/46, 1973. 2. USSR author's certificate No. 517931, cl. G 11B 15/46, 1975.