RU2195787C2 - Device forming spiral scan for tv coordinators - Google Patents

Abstract

FIELD: television equipment. SUBSTANCE: invention is related to devices forming rectangular spiral scan. Technical result of invention lies in generation of search raster in TV coordinators intended for search, detection and determination of coordinates of point objects located in field of vision of camera tube. Proposed device ensures independence of maximum raster of cathode-ray tube of changes of supply voltage as circuit controls not number of turns of scan but voltage values across outputs of generators of amplitude-modulated scan voltage of channels X and Y corresponding to position of scanning aperture of camera tube on edges of raster. Device makes it possible to make short-time stop of scan on any turn and in any phase with its subsequent cut-off or further scanning from point of stop as well as starting of scanning within field of vision with start in point having any coordinates. EFFECT: enhanced functional reliability of device. 3 dwg

Description

 The invention relates to television technology, and in particular to devices for generating a search raster in television coordinators designed to search, detect and determine the coordinates of point objects in the field of view of the coordinator.

 A device is known for forming a rectangular spiral sweep containing a clock pulse generator, from the output of which clock pulses through the prohibition block are fed to the input of a pulse shaper having two outputs, from one of which pulses of the same polarity are fed to the trigger and input of the logical element And (matching circuit) and to the inverter input of one of the channels, and from the other output to the inverter input of another channel. From the outputs of the inverters, the out-of-phase sequences of bipolar pulses arrive respectively at the inputs of the switches of the two scan channels, the second inputs of which receive pulses from the opposite arms of the trigger. The switches generate at their outputs two sequences of pulses offset from one another, each of which is fed to the input of the corresponding generator, from the outputs of which the amplitude-modulated (AM) scan voltages of the channels X and Y, mutually shifted in phase by 90 degrees, are fed to the deflecting system CRT, which ultimately leads to the movement of its aperture along a rectangular spiral path extending from the center with a constant linear scanning speed. Upon completion of the scan, the required number of turns of the spiral, the counter of the number of revolutions of the spiral gives a pulse to the input of the circuit And, to the second input of which the pulses of the shaper. When these signals coincide, an impulse appears at the output of circuit And, which triggers a single-shot, generating a reset pulse, which is fed to the inputs of the two channel keys and to the reset inputs to zero of the pulse shaper and the counter of the number of revolutions of the spiral, as a result of which the scan voltages of both channels, forming the reverse course of the sweep, and the shaper and counter are brought to the initial states [1].

 The disadvantages of the known device include the independence of the number of turns of the spiral from the supply voltage of the device, which, for example, when lowering the supply voltage can lead to a decrease in the maximum size of the raster, that is, to loss of information from fragments located at the edges of the field of view when using a scan in transmitting television handsets. In addition, this device cannot be used, for example, in television coordinators, since the device’s scheme does not allow short-term stopping of the scan at any point of the raster to analyze the received signal and, in the case of receiving a signal, for example, from the desired point object, switch to tracking mode directly at the stopping point, otherwise continue to sweep from the same place. Similarly, when the object is lost in the tracking mode, when switching to the repeated search mode, the device does not allow to begin the formation of a spiral scan from the place of loss.

 The aim of the invention is to eliminate the dependence of the size of the raster on changes in the supply voltage, the ability to follow the instructions coming to the device from the outside, to stop the sweep in any phase of the trajectory, followed by its continuation from this phase and within the field of view of the transmitting CRT to form a sweep with the beginning at the point having any coordinates.

This goal is achieved by the fact that a comparator, a sawtooth voltage generator, the output of which is connected to the first input of the comparator, a drive, the output of which is connected to the second input of the comparator, a normalized pulse generator, the output of which is connected to the charging input of the drive, is introduced into the known device for forming a spiral scan channel and shift switch triggers operating in counting mode, a differentiating circuit whose output is connected to the input of the normalized pulse generator and counting in by the channels of the channel switch trigger and the shift trigger, triggered by pulses of opposite polarity, the direction trigger, operating in the counting mode, to the second output of which the input of the differentiating chain is connected, and the input is connected to the output of the comparator,
the first OR circuit, the second input of which is connected to the output of the comparator and the input of the direction trigger, and the output is connected to the reset input of the sawtooth generator to zero, the stop trigger operating in separate start mode, the first output of which is connected to the stop input of the sawtooth generator, and on the first input of which the sweep enable command comes from the coordinator, the second OR circuit, the output of which is connected to the drive input to zero, the third OR circuit, the output of which is connected to the second input m trigger stop threshold device, whose output is connected to the first input of the third OR circuit, the second input of the second OR circuit and inputs grounded keys channels X and Y, and two inputs connected respectively to the outputs of the generators AM channel scanning voltages X and Y,
a strobe generator, the input of which is connected to the second input of the third OR circuit, from the coordinator receives a short-term stop sweep command, the first matching circuit for two inputs, the first input of which from the coordinator receives a command to enter the tracking mode, and the second input of which is connected to the output the gate generator, and the output of the first matching circuit is connected to the first inputs of the first and second OR circuits, the second and third matching circuits of positive signals to four inputs, the outputs of which are connected to the second inputs of the gene Ator AM scans channels voltage X and Y,
the fourth and fifth matching circuits of negative signals to four inputs, the outputs of which are connected respectively to the third inputs of the generators AM of the scan voltage of channels X and Y, the fourth inputs of which receive voltage from the tracking scan of the coordinator, the first inputs of the second and third matching circuits and the first inputs of the fourth and the fifth matching circuit are connected in pairs respectively to the first and second outputs of the stop trigger, the second inputs of the second and fourth matching circuits and the second inputs of the third and fifth matching circuits The outputs are connected in pairs to the first and second outputs of the channel switch trigger, respectively, the third inputs of the second and fifth matching circuits and the third inputs of the third and fourth matching circuits are connected respectively to the first and second outputs of the direction trigger, and the fourth inputs of the second, third, fourth and fifth matching circuits connected to the first output of the shift trigger.

 In Fig.1 shows a structural electrical diagram of the proposed device, in Fig. 2 shows temporary diagrams of voltages and currents explaining the operation of the device, FIG. 3 shows the field of view of a CRT and the trajectory of its scanning aperture, which corresponds to the diagrams shown in FIG. 2.

The spiral scan forming device for television coordinators includes a sweep stop trigger 1, a sawtooth voltage generator (GPN) 2, a comparator 3, a drive 4, a first OR circuit ₁ 5, a direction trigger 6, a differentiating circuit 7, a normalized pulse generator (STI) 8, a trigger channel switch 9, shift trigger 10, second, third, fourth and fifth coincidence schemes for four inputs And ₂ 11, And ₄ 12, And ₃ 13, And ₅ 14, the generator of amplitude-modulated scan voltage channel X AMGRX 15, the generator of amplitude modulated the first scan voltage of channel Y AMGRY 16, CRT cathode ray tube 17, third OR ₃ 18 circuit, strobe generator (GS) 19, first coincidence circuit I ₁ 20, second OR ₂ 21 circuit, threshold device PU 22, channel keys X ( Cl. X) 23 and channel Y (Cl. Y) 24.

 The device operates as follows.

At time t ₁ (Fig. 2), the first input of the scan stop trigger 1 receives a pulse from the scan enable command (Fig. 2a), which switches the trigger 1 to the scan enable state, as a result of which a voltage appears at the first output of the scan stop trigger 1 positive polarity (Fig. 2b), which is fed to the control input of the GPN 2 and puts the latter into working condition. GPN 2 begins to generate a sawtooth voltage, which from its output (Fig. 2d) is supplied to the first input of the comparator 3, in which the magnitude of the voltage acting on its second input (Fig. 2d) compares the voltage from the output of the drive 4 with the output voltage of the GPN 2 acting at the first entrance. Since at the time the device starts to work, the voltage at the output of the drive 4 is equal to zero, the comparator 3 gives an output at the time t ₁ pulse (Fig.2e), which appears when the voltage of the voltage of the load condition 2 is exceeded.

This pulse, passing from the input OR ₁ 5 to its output, is fed to the reset input to zero GPN 2 and puts the latter into the mode of forming a sawtooth voltage back stroke, after which GPN 2 immediately begins to form a forward stroke of the next sawtooth voltage (Fig.2g ) The same output pulse of the comparator 3 is supplied simultaneously to the trigger of the direction 6 trigger, which operates in the counting mode, switches it, as a result of which, for example, a negative potential appears on the second output of the trigger 6 connected to the input of the differentiating circuit 7 (Fig. 2g), and on the first - positive (fig.2z). At the moment of the output of the differential circuit 7, a positive impulse is formed (Fig. 2i), which, entering the GNI 8 input, launches the latter. STI 8 is a one-shot, the output pulses of which, having exactly the same amplitude and duration (Fig.2k), entering the charging input of the drive 4, increase with the arrival of each pulse the voltage at its output by one stage (Fig.2d).

At the same time, a positive pulse from the output of the differential circuit 7 arrives at the trigger of the channel switch 9, which operates in the counting mode from the positive triggering pulses, and switches it (Fig. 2l and Fig. 2m). The same pulse is fed to the input of the shift trigger 10, which also works in counting mode, but does not switch it (Fig.2n), since this trigger is triggered by negative pulses. At time t ₂ , when the voltage at the output of the ГПН 2 (Fig. 2d) exceeds the voltage at the output of the drive 4 (Fig. 2d), an impulse appears at the output of the comparator 3 (Fig. 2e), which switches the trigger of direction 6 and forms a reverse stroke sawtooth voltage GPN 2 (Fig.2g). The trigger of direction 6 is switched and at its second output, to which the input of the differential circuit 7 is connected, a negative voltage drop appears (Fig.2z), which generates a negative pulse at the output of the differential 7 (Fig.2i).

This negative pulse switches the shift trigger 10 (fig.2n), without affecting the state of the other circuits, which are switched only by positive pulses of differential 7. In the time interval t ₂ -t ₃ GPN 2 again forms a direct sawtooth voltage path (Fig.2g), when exceeding which the voltage value at the output of the drive 4 (fig.2d) at the time t ₃ triggers the comparator 3 and at its output (fig.2e) there is a pulse that switches the trigger direction, causing a positive at its first output (fig.2z) voltage drop that, in its in turn, it creates a positive pulse at the output of differential 7 (Fig. 2i), which switches the trigger of channel 9 switch, STI 8 is launched and its pulse, arriving at the charging input of drive 4, increases the voltage at its output by one more step (Fig. 2e) .

 Further, the entire described process is periodically repeated, but as a result of a constant increase in the output voltage of the drive 4 by one step with the arrival of each GNI pulse 8, the duration of the repetition period of the output pulses (Fig. 2e) of the comparator 3 increases, which, in turn, increases pulse repetition periods and all other circuits (1,2,6,7,8,9,10). triggered by these pulses directly or through other circuits.

The voltages from the outputs of all the triggers go to the inputs of the four-input coincidence circuits And ₂ 11, And ₄ 12 scan channels along the X-axis and coincidence circuits And ₃ 13, And ₅ 14 scan channels along the Y-axis. If the inputs coincide at the inputs of the coincidence circuits And ₂ 11 and And ₃ 13 positive voltages, positive voltages also occur at their outputs, and if the inputs of coincidence circuits And ₄ 12 and And ₅ 14 match negative voltages, the voltages at their outputs are negative, and in any other cases the voltages at the outputs of all four-input coincidence circuits 11, 12, 13 and 14 are equal to zero. Pairwise connected first inputs of the matching circuits 11 and 13 and matching circuits 12 and 14 are connected respectively to the first and second outputs of the trigger stop 1 (fig.2b and figv). The second inputs of the matching circuits 11 and 12 and the second inputs of the matching circuits 13 and 14 are connected in pairs to the first and second outputs of the trigger of the channel switch 9 (Fig. 2l and Fig. 2m).

 Pairwise connected third inputs of the matching circuits 11 and 14 and the third inputs of the matching circuits 12 and 13 are connected respectively to the first and second outputs of the trigger direction 6 (fig.2z and fig.2zh). All fourth inputs of coincidence circuits 11, 12, 13 and 14 are connected to one output of shift trigger 10 (Fig. 2h). At the outputs of coincidence circuits 11 and 12, positive and negative pulses are generated respectively (Fig. 2o and Fig. 2p), which arrive respectively at the second and third inputs of AMGRH 15, and at the outputs of matching circuits 13 and 14, positive and negative pulses are generated respectively (Fig. 2c and 2t), which are respectively fed to the second and third inputs of AMGRY 16. The polarity of the pulses at the inputs of the AMGRX 15 generators and AMGRY 16 determines the direction ix changes sweep voltage.

The presence of 15 and 16 positive pulses at the inputs of the generators causes a positive increase in the output voltages of the scan generators of both channels, and the presence of negative pulses at the inputs of the same generators causes a negative increase in the output voltages of the generators. With the simultaneous presence of zero potentials at any inputs of AMGRH 15 (Fig.2o, Fig.2p time intervals t ₃ -t ₄ ; t ₅ -t ₆ , t ₇ -t ₈ , etc.) or AMGRY 16 (fig.2c , fig.2t time intervals t ₂ -t ₃ ; t ₄ -t ₅ ; t ₆ -t ₇ , etc.) at the outputs of the voltage generators of the scan (fig.2p and fig.2u) are stored those voltage values that had place at the outputs of the generators until the simultaneous appearance of these zero potentials and these values are stored until then. until a potential other than zero appears on one of the inputs.

The duration of the pulses at the inputs of the generators with each repetition period increases by a constant value that; ultimately, it provides amplitude modulation of the output voltages AMGRX 15 and AMGRY 16, since the rate of increase or decrease of the scan voltages is equal and constant for them. Thus, until time t ₁₂ , two voltages are formed in channel X and channel Y, modulated in amplitude and phase shifted by 90 degrees (Fig. 2p and Fig. 2u). This voltage, controlling the currents of the scan generators in the deflecting windings of the CRT 17, forms a rectangular spiral scan, which causes the aperture of the CRT 17 to scan along the same path (Fig. 3 time interval t ₁ -t ₁₂ ). In the scanning process, for example, at time t ₁₂ , an image of an object appears in the scanning aperture. At this moment, the second input of the OR ₃ 18 circuit and the input of the strobe generator GS 19 from the television coordinator will receive an impulse for a short stop scan command (Fig.2x).

This pulse, passing through OR ₃ 18, enters the second input of stop trigger 1 (Fig.2h), switches it, as a result of which the negative potential appears at the stop input of GPN 2 from the first output of this trigger (Fig.2b), which stops growth sawtooth voltage (FIG. 2d). In this case, the negative potential from the first output of stop trigger 1 will act on the first inputs of the coincidence circuits And ₂ 11 and And ₃ 13, and at the first inputs And ₄ 12 and And ₅ 14 - the positive potential from the second output of this trigger, that is, such potentials, under which the coincidence conditions are not fulfilled for all the indicated circuits, as a result of which zero potentials appear on all inputs of AMGRX 15 and AMGRY 16 (Fig. 2o, Fig. 2p, Fig. 2c, Fig. 2t) and the voltage changes stop on their outputs ( fig.2p and fig.2u). Starting from time t ₁₂ and until the next comparison pulse of comparator 3 appears (Fig. 2e), at the outputs of circuits 4,8,9 and 10 there are potentials that were at the time of stopping at t ₁₂ . At the same time, the stop pulse starts the GS 19, which generates a strobe pulse (Fig.2c).

This strobe pulse is fed to the first input AND ₁ 20. The strobe pulse duration (time interval t ₁₂ -t ₁₄ ) is set so that for a time less than or equal to the duration of this pulse, the television coordinator can analyze the received signal and decide whether to start tracking behind the object or continue the movement of the aperture along the path of a rectangular spiral scan, that is, a search. In the case under consideration, for example, the object is recognized by the coordinator and at time t ₁₃ there appears an impulse of the command to switch to the tracking mode (Fig.2sh), which, having passed to the output I ₁ 20 (Fig.2sh), goes to the first inputs of two circuits OR ₁ 5 and OR ₂ 21, having passed to the outputs of which (FIG. 2e and FIG. 2yu, respectively), it goes to the reset inputs of the tap 2 and drive 4, respectively, and sets the voltage at their outputs to zero. From this moment, the device stops the formation of a rectangular spiral scan and the follow-up voltage, which in the case under consideration in the time interval t ₁₃ -t ₁₅ provides continuous tracking of the object, creates outputs AMGRX 15 and AMGRY from the coordinator to the fourth inputs of AMGRX 15 and AMGRY 16 16 voltages (Fig. 2p and Fig. 2u), which at any time correspond to instantaneous values of the coordinates of the object.

At time t ₁₅ , for example, an object is lost (tracking failures). At the first input of stop trigger 1 from the coordinator, a sweep enable pulse appears (Fig. 2a), and at its first output a positive potential appears, GPN 2 starts to work, and at a point with coordinates corresponding to the place where the object was lost, a spiral rectangular scan starts from zero ( fig. 2p, fig. 2u and fig. 3 - point t ₁₅ ). When at the time t ₂₃ at the output AMGRY 16 the amplitude-modulated voltage of the triggering voltage of the PU 22 reaches the output of the latter, a comparison pulse appears (Fig. 2f), which is fed to the inputs of the grounded keys Cl. X 23 and Cl. Y 24 and resets to zero the voltage at the outputs AMGRX 15 and AMGRY 16, goes to the second input OR ₂ 21, passing to its output, resets drive 4 to zero and, passing through OR 18, switches the stop trigger 1. As a result, the sweep forming device goes into the initial state and stays in it until about t of the coordinator, there will be no impulse for the sweep enable command, after which the device will begin to form a sweep with a start at a point with coordinates X = 0 and Y = 0.

 The proposed device provides the formation of a rectangular spiral scan, in which the maximum size of the raster does not depend on changes in the supply voltage, allows for a short stop of the scan at any turn and in any phase with its subsequent shutdown or further continuation of the scan from the stop point, as well as to run the scan within field of view with a beginning at a point having any coordinates.

Sources of information
1. USSR author's certificate 807501, class N 04 N 3/16, publ. 02/23/81, BI 7.

Claims (1)

 A device for forming a spiral scan for television coordinators, containing two identical generators of amplitude-modulated voltage of channels X and Y, the outputs of which are connected to the inputs of the cathode ray tube, two grounded keys of channels X and Y, the outputs of which are connected to the first inputs of the amplitude-modulated voltage generators characterized in that a comparator is introduced, a sawtooth voltage generator, to the output of which the first input of the comparator is connected, a drive, the output of which is connected to the second at the input of the comparator, a normalized pulse generator, the output of which is connected to the charging input of the drive, channel and shift triggers operating in the counting mode, a differentiating circuit whose output is connected to the input of the normalized pulse generator and the counting inputs of the channel switch trigger and the shift trigger, triggered by pulses of opposite polarity, a directional trigger operating in counting mode, to the second output of which the input of the differentiating chain is connected, and the input is connected to the output of a device, the first OR circuit, the second input of which is connected to the output of the comparator and the input of the direction trigger, and the output is to the reset input of the sawtooth voltage generator to zero, the stop trigger operating in separate start mode, the first output of which is connected to the stop input of the sawtooth voltage generator, the first input of which the sweep enable command comes from the coordinator, the second OR circuit, the output of which is connected to the reset input to zero of the drive, the third OR circuit, the output of which is connected to the second input ohm of the stop trigger, a threshold device whose output is connected to the first input of the third OR circuit, the second input of the second OR circuit and the inputs of the grounded keys of channels X and Y, and the two inputs are connected respectively to the outputs of the amplitude-modulated scan voltage generators of channels X and Y, generator gate, at the input of which, connected to the second input of the third OR circuit, the coordinator receives a short-term stop scan command, the first coincidence circuit for two inputs, the first input of which from the coordinator command tracking tracking, its second input is connected to the output of the strobe generator, and the output is connected to the first inputs of the first and second OR circuits, the second and third schemes are the coincidence of positive signals to four inputs, the outputs of which are connected to the second inputs of the amplitude-modulated scan voltage generators channels X and Y, the fourth and fifth schemes for matching negative signals to four inputs, the outputs of which are connected respectively to the third inputs of the amplitude-modulated voltage of the channel sweeps X and Y, the fourth inputs of which receive voltage from the tracking sweep of the coordinator, with the first inputs of the second and third matching circuits and the first inputs of the fourth and fifth matching circuits connected in pairs to the first and second outputs of the stop trigger, the second inputs of the second and fourth matching circuits and the second inputs of the third and fifth matching circuits are connected in pairs to the first and second outputs of the trigger switch channels, respectively, the third inputs of the second and fifth matching circuits and the third inputs of the third and fourth The coincidence circuit is connected respectively to the first and second outputs of the direction trigger, and the fourth inputs of the second and fifth coincidence circuits are connected to the first output of the shift trigger.

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