SU1474704A1 - Graphic data input unit - Google Patents

Abstract

The invention relates to the field of automation and computer technology, in particular to devices for reading graphic information, and can be used in automated design systems. The purpose of the invention is to improve the noise immunity of the device for reading graphic information. The goal is achieved by analyzing the position of the read pulse relative to the coordinate remover, which is ensured by introducing into the device a group of elements AND, a group of gate formers, elements AND, OR, a trigger and formers of reset pulses. 2 Il.

Description

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The invention relates to the field of automation and computer technology, in particular, to devices for reading graphic information with subsequent input into electronic computers and can be used in automated design systems.

The purpose of the invention is to improve the noise immunity of the device.

1 shows a block diagram of the device; on fkg.2 - functional block diagram of the control unit.

The device contains a tablet 1, elements OR 2, the first 3 and second 4 switches, a 5-coordinate puller with a compensation frame, an amplifier 6, a control block 7, a coordinate register 8, a compensation block 7, a group of gate generators 10 and 11, a reset pulse driver 12, element OR 13,

trigger 14, a group of elements 15 and 16 and an element 17. In addition, the outputs 18-23 of the control unit and the input 24 are shown.

The control unit (Fig. 2) contains a generator of 25 pulses, an AND 26 element, a counter 27, And 28-31 elements, counters 32-34, an And 35 element, a delay element 36.

The device works as follows.

In the initial state, all the memory elements, except for the counter 33 of the control unit 7, which has at the output the code of the last bus in the group, are in the zero state. The generator 25 is connected through the element 28 to the counting input of the counter 32. The inputs of the switches 3 and 4 are connected to the outputs of the counters 32 and 33, which in the initial

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state corresponds to the connection of the last bus in the first group. When the puller is located 5 coordinates on the surface of the tablet 1 and the Start button (not shown) is pressed, the pulses from the generator 25 through the element 28, on the second input of which the Log level, 1 is present, arrive at the counting input of the counter of 32 groups. tire in a group. In this case, the counter 32 counts the number of polled groups lying to the left of the center of the inductance of the puller in 5 coordinates. On the leading edge of the polling pulse, the driver 10 generates a gating pulse of positive polarity, a. shaper 12 generates a positive polarity pulse with a duration equal to the sum of the duration of the interrogation pulse and the delay time of the pulse induced in the coil inductance of the coordinate remover relative to the interrogation pulse.

The shaper 11 forms a gating pulse of positive polarity along the trailing edge of the interrogation pulse. If the tire is polled in the sensing zone of the puller 5 coordinates and a pulse current flows through the bus, a differential pulse is induced in the coil. If the center of the coil is to the left of the polled tire, then a right impulse is induced in it. The left and right pulses go out, are polarized and arrive at the output of amplifier 6. The pulses of positive polarity arrive at the first output9 and the pulses of negative polarity through the inverter arrive at the second output. If a right pulse is induced in the inductor of puller 5, then two pulses are generated at the output of amplifier 6, first at the first and then at the second outputs. &Amp; t if a left pulse is induced at the inductor, then two pulses are formed at the output of amplifier 6 the second and then 1 at the first exits. The first output is connected to the second input element And 16, and the second output to the first input element And 15. Four cases are possible.

In the first case, a right impulse is induced in the inductance coil. In this case, the formers 10 and 12

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on the leading edge of the polling pulse from block 7, pulses are formed. The impulse from the imaging unit 10 through the element OR 13 is fed to the first input of the element AND 16. From the first output of the amplifier 6 to the second input of this element comes another impulse from the coordinate remover. Then, at the output of the element AND 16, a pulse is generated, which triggers the trigger 14. On the falling edge of the interrogation pulse, the driver 11 generates a pulse, which through the element OR 13 enters the second input of the element 15, the first input of which contains the signal from the second amplifier 6. the output of the element 15 forms a pulse that arrives at the first input of the element 17, the second input of which contains a signal - level log.1 from the output of the trigger 14; the output of the element 17 forms a signal until those nops until the trigger 14 overturns odnoe state on the falling edge of the pulse generated by pulse shaper 12. The output from the AND gate 17 is fed to the input of block 7, 1

In the second case, a left pulse is induced in the inductance coil. In this case, the pulse from the imaging unit 10 through the element OR 13 enters the second input of the element 15E and at the first input of which there is a signal from the second output of the amplifier b. The pulse from the output of the element And 15 through the element And 17 is not fed to the input of block 7, since at the second input of the element And 17 there is a signal - level Log.O, the trigger 14 is not yet cocked. On the falling edge of the interrogation pulse, the signal from the generator 11 through the element OR 13 enters the input of the element AND 16, on the other input of which there is a signal from the output of amplifier 6, the pulse from the output of the element AND 16 will trigger trigger 14. Signal - level Log.1 from the output the trigger is present at the second input of the element And 17, At the first input, the pulse from the output of the element And 15 has already ended. On the falling edge of the pulse of the driver 12, the trigger 14 is reset. At the output of the element And 17 does not form a pulse

In the third case, an interference pulse is induced in the inductance coil, which coincides with the front front of them

pulse survey. With ems, the output element And 17 does not form a pulse.

In the fourth case, an interference pulse is induced in the inductance coil, which coincides with the trailing edge of the interrogation pulse. In this case, the output element And 17 does not form a pulse.

In the following, the operation of the device is considered when the impulse impulse that induces a pulse in the inductance coil is right, and the front and rear edges of this impulse coincide with the gating impulse of the formers 11 and 10. Then, at the output of the And 17 element, a pulse is received the counter 27 and the second input of the element AND 31, on the first input of which there is a resolution (level Log.1) from the element AND 26. The pulse formed at the output of the element And 31 transfers the counter 33 into the state O. at the output, which leads to the switching of the generator 25 from the counter 32 to the counter 33 through the element 28, on the second input of which there is a resolution (level Log.1) from the first discharge of the output of the counter 27.

Subsequent polling is continued in the group whose code is fixed by the counter 32. Tire counting, starting with the first tire lying to the left of the center of the inductor, is done by the counter 33. When a pulse is generated from the tire lying to the right of the center of the inductor, block 7 enters pulse. The counter 27 changes its state, which causes the generator 25 to switch from the counter 33 to the counter 34 through an element 30, the second input of which has the enable signal from the second bit of the counter 27. The subsequent operation of the device continues in the exact count. With each polling pulse of the generator 25, the compensation unit 9 generates a reference compensation pulse, which is fed to the compensation puller of the 5-coordinate puller. In this case, with the first polling pulse, the compensation unit 9 generates a compensating pulse of maximum amplitude :. Counter 34 counts the number of pulses from generator 25 until fully compensated.

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pulse induced in the inductor from the bus. As soon as the pulse, the amplitude compensation unit 9 becomes less than the pulse from the bus, a pulse is generated that puts the counter 27 into the next state. In this case, the counter 27 changes its vco stand at the output.

Element 35 forms a sync pulse and the total code of the group number, bus number and exact reference code are rewritten to registers 8. By the same pulse, the delayed time delay element 36 for overwriting the data of the counters 32-34, the device returns to its original state and is ready to determine the next coordinate of the graphic information point. °

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Claims (1)

Invention Formula A device for reading graphic information containing a tablet with a system of mutually orthogonal coordinate buses divided into groups, OR elements whose inputs are connected to the outputs of the first switch, and outputs connected to the coordinate buses of the corresponding groups connected to the outputs of the second switch, coordinate remover whose input connected to the output of the compensation unit, and the output is connected to the input of the amplifier, the control unit, the first, second and third outputs of which are connected to the information inputs of the first and volts switch and compensation unit, respectively, the fourth output is connected to the information inputs of the coordinate registers, the synchronization inputs of which are connected to the fifth output of the control unit, and the output is the output of the device, in which, in order to improve the noise immunity, a group of elements And, one inputs of which are connected to the corresponding outputs of the amplifier, a group of gate formers, the synchronization inputs of which are connected to the sixth output of the control unit connected to the syncro the input inputs of the first and second switches, the OR element, the inputs of which are connected to the outputs of the group gateway drivers, and the output is connected to other inputs of the AND group elements, the AND element, one input of which is connected to the output of the first AND group element, and you have a single input connected with the course is connected to the synchronous input-output of the second element AND group, control unit house, the steering unit is connected to the output reset pulses, the synchronizing gate of the reset pulses, and whose direct input is connected to the sixth output of the control unit, and a trigger, the output is connected to another input of element I. the reset pulse, and my the output is connected to another input element I.