SU453715A1 - DEVICE FOR READING GRAPHIC INFORMATION - Google Patents

Description

one

The invention relates to the field of automation and computer technology and is used to enter graphic information into an electronic computer, and can be used to encode in rectangular coordinates both two-dimensional information — graphs, drawings, etc., as well as three-dimensional information in the form of volumetric models. .

A device for reading graphic information is known, comprising a tablet, a sight-emitter with a starting circuit, ultrasound receivers connected to an amplifier, a reference signal generator with drivers, counters, and a code output unit.

The ultrasound receivers of the known device have a spatial extent (lines in the two-dimensional version of the device, the plane in the three-dimensional).

The aim of the invention is to improve the accuracy of the device, for which the proposed device is equipped with point ultrasound receivers with a spherical radiation pattern, a phase shifter, through which the reference signal generator is connected to one of the meander drivers, frequency subtraction triggers connected to the counters, to the corresponding amplifiers and shaper reference squares, integrators connected to a block of output codes and counters, and a frequency divider connected to the trigger of the viewfinder emitter and one of the generators reference meanders, the point of ultrasound receivers placed on the plate at its coordinate

axes and at their intersection.

The block diagram of the proposed device shown in the drawing.

The device in a two-dimensional version contains a tablet 1, a sight-emitter 2 and three point ultrasound receivers 3 connected with it through the air medium, located on the coordinate axes of the tablet and at the point of their intersection. With the output of the generator of the reference signals 4 are connected the inputs of two identical shapers 5 of the reference meanders, one directly and the other through the phase shifter 6. To the output of one of the driver of the reference meanders, the input of frequency divider 7 is connected, the output of which is connected to the input

launching circuit of the viewfinder-radiator 8. The output of each ultrasound receiver is connected to the input of one of three identical 1–1 subschemes containing amplifier 9, two frequency subtraction trigger 10 and counter 11. At the same time,

In the subcircuit, the amplifier output is connected to two switching inputs of each of the two frequency subtraction triggers, two prohibiting inputs of one of these triggers are connected to the outputs for direct and inverse

signals from one of the drivers of the reference

and two prohibiting inputs of another trigger are connected to the same outputs of the second driver. The outputs of the two frequency subtraction triggers are connected to the two inputs of the counter. In addition, the device contains two identical integrator 12 and a block of 13 pins on the perforator and in the digital computer, and the outputs of the counters through the integrators are connected to the inputs of the output unit in such a way that the nodshema counter. connected to the ultrasound receiver located at the intersection point of the tablet axes is connected to both integrators, and each of the two remaining counters is connected to another input of only one of the corresponding integrator.

The device works as follows.

The object of coding the roll on tablet 1, then combines the center of the sight-emitter 2 with the point Ob fixed on the tablet, and then sets zero in integrators 12 and the initial values of the distance from the center of the sight-emitter - point M to ultrasound receivers 3 at points A , B, C in counters 11. After these operations are performed, the coordinates of the points of the coded object will correspond to the coordinate system with the origin at the point Ob. If you want to choose the origin of coordinates at another point of the tablet, for example, the O point, you will be placed The scopes emitter are at point O and re-set zero in integrators 12.

In the process of tracing by the creeper-emitter of the lines of the coded object, the distance MA, MB, MS and, accordingly, the delays of the signals sent by the sight-emitter and received at points A, B, C relative to the reference meander are changed. The received ultrasound signal using an amplifier 9, which includes a resonant amplifier tuned to the frequency of the emitted signals and a circuit for determining the moments of the amplified zero crossing, turns into a periodic pulse sequence of about 0.2 microseconds. The connection of the starting circuit of the radiator 8 to the driver 5 of the reference meanders through the frequency divider 7 provides ultrasound emission at the most favorable frequency from the point of view of the range of acoustic communication between the radar visor and the ultrasound receivers.

With a fixed sight, for example, at the starting point Ob, the pulses coming from the output of amplifier 9 to the switching inputs of two frequency subtraction triggers 10 are strictly synchronized with the reference meanders supplied to the inhibit inputs of the same triggers from the formers 5. For each trigger each time when the switching impulse arrives from the amplifier, a prohibiting signal acts, while a switching impulse acting simultaneously on the other trigger arm will not be prohibited - the corresponding prohibiting input p It is given a signal inverted with respect to the banning. In this case, both triggers are in a stable state and do not affect the counter 11.

If the target-emitter is shifted from the starting point so that the change in the delay of the pulses coming from the output of the amplifier 9 to the switching inputs of the trigger 10,

relative to the reference meanders is equal to a quarter of the period of the following meanders, then one of the triggers necessarily switches to another state. This is because the phase shifter 6, through which the reference signal generator 4 is connected to one of the two drivers 5, performs a phase shift of the signals by -. Therefore, the length of time between fronts

the main and phase-shifted reference meanders is equal to one quarter of their period, therefore, at the indicated displacement of the sight-emitter at the inhibiting inputs of one of the triggers, the switching signal acts on the input at which it is earlier when the switching pulse from the amplifier arrives absent, and vice versa. Switching one of the triggers to another state

causes the formation of a single pulse in the counter 11, operating according to the known scheme of sequential reversible counting of single displacements, and the addition of this impulse — a single displacement with the initial

the distance from the center of the viewfinder to the ultrasound receiver.

With the continuous movement of the visor radiator with a constant speed relative to

the ultrasound receiver at the outputs of the frequency subtraction triggers will be rectangular signals with a pulse duration equal to half the tracking period, shifted in phase relative to each other by a quarter

follow up period and frequency

f

(one)

star + v

where / o is the frequency of the reference meanders,

HC - the speed of the movement of the sight-emitter, VSB-speed of sound in the air.

Formula (1) is derived from the well-known formula describing the Doppler phenomenon in a moving radiation source. The frequency / is equal to the difference between the frequencies of the emitted and received signals multiplied by the frequency division factor of the reference meander when transmitting this signal to the sight-emitter.

Thus, at any moment in time, the three counters 11 will contain the actual distance values MA, MB and

MS. The transition from these quantities to the coordinates X and Y is carried out according to the formulas

u (MB) - (MA) U. „.

y (MS

 -25s

where AB and BC are the distances between the ultrasound receivers at points A and B, B and C, respectively; XQ and SV - the initial values of the coordinates.

Calculations using formulas (2) and (3) are performed by digitally integrating the MA, MB, and MS values over their increments and algebraically summing the two integral sums when obtaining one coordinate. Both of these operations are performed in one integrator 12 for the X coordinate and similarly in the other integrator 12 for the Y coordinate. The division into AB and BC is done by discarding the low bits of the X - Y codes. The X and K codes from the integrators go to block 13 from where they are issued parallel-to, therefore to the perforator and parallel to the digital computer. The command for generating the code is generated by the block 13 itself, checking the code X or Y or the code X and Y simultaneously for the multiplicity of the specified increment of the coordinate. In the one-time coding mode, an operator gives a code output.

The three-dimensional version of the proposed device includes a fully two-dimensional version.

and additionally contains a point ultrasound receiver 3 located at the D point of the OZ axis passing through the B point of the tablet, amplifier 9, two flip-flops 10, counter 11 and integrator 12. Z coordinate can be calculated using the formula

  (MB) (MR) - 7 ,,.

Subject invention

A device for reading graphic information comprising a tablet, a viewer-emitter with a starting circuit, ultrasound receivers connected to amplifiers, a generator of reference signals, counters, an output unit and drivers that, in order to improve the accuracy of the device, it contains a phase shifter connected directly and through a reference signal generator to the shapers of the reference meanders, frequency subtraction triggers connected to the counters to the corresponding amplifiers of the shapers of the reference meanders c, integrators connected to an output unit n with counters, a frequency divider connected to the launching circuit of the sight-emitter and one of the drivers of the reference meanders, and the point ultrasound receivers are placed on the tablet on its coordinate axes and at the point of their intersection.