US 3790704 A
A television camera views a representation of a pattern to be knitted by a knitting machine. A television picture tube displays a monochrome image of the pattern and coloured picture elements, each representing stitch information stored at an individual address in a memory, are superimposed upon the pattern image so that the correspondence between the stored information and the original pattern may be determined. A keyboard enables pattern information to be progressively entered in a memory, each stitch so entered appearing immediately as a coloured element in a display. Any portion of the pattern information stored in the memory may be displayed at will. A pulsating marker element shows the position in the displayed pattern at which information will be entered upon actuation of a key. Automatic return and pattern line advance and "tabulator" return to preselected positions in the pattern may be effected.
Description (OCR text may contain errors)
United States Patent [191 Collomosse et al.
[ Feb. 5, 1974 PATTERN CONTROL SYSTEM FOR CONTROLLING TEXTILE MACHINERY  Assignee: Louis Newmark Limited, Croydan, Surray, England 22 Filed: Dec. 15, 1972 211 App]. No.: 315,287
 Foreign Application Priority Data Dec. 17, 1971 Great Britain 58,633/71  U.S. Cl. 178/68, 178/52 R, 178/54 R, 178/54 CD, l78/DlG. 22
 Int. Cl. H04]! 7/18, H04n 9/02  Field of Search 178/6.8, DlG. 22, 5.2 R, 5.4 R, l78/5.4 CD; 340/324 AD  References Cited UNITED STATES PATENTS 3,7l9,777 3/1973 von Reichenbach l78/6.8 3,742,125 6/1973 Siegel 178/52 R Primary Examiner-Howard W. Britton Attorney, Agent, or Firm-Lawrence E. Laubscher  ABSTRACT A television camera views a representation of a pattern to be knitted by a knitting machine. A television picture tube displays a monochrome image of the pattern and coloured picture elements, each representing stitch information stored at an individual address in a memory, are superimposed upon the pattern image so that the correspondence between the stored information and the original pattern may be determined. A keyboard enables pattern information to be progressively entered in a memory, each stitch soentered appearing immediately as a coloured element in a display. Any portion of the pattern information stored in the memory may be displayed at will. A pulsating marker element shows the position in the displayed pattern at which information will be entered upon actuation of a key. Automatic return and pattern line advance and tabulator return to preselected positions in the pattern may be effected.
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F/G/Q PATTERN CONTROL SYSTEM FOR CONTROLLING TEXTILE MACHINERY BACKGROUND OF THE INVENTION This invention relates to a pattern control system for controlling a textile machine producing patterned textile material in response to pattern information stored in a memory device. The invention has particular, though not exclusive, application in the control of knitting machines and will be particularly described as applied to that purpose. It will be apparent to those skilled in the art, however, that the invention may also be applied to controlling other machines for producing patterned fabrics, in which a plurality of successively or simultaneously performed operations are required to be varied in order to produce the required pattern.
It is known from United Kingdom Patent Specification No. 1,199,291 to provide opto-electronic picture storage apparatus including a cathode ray tube display of an image by means including a respective feedback loop for each picture element, so that a picture to be stored may be introduced point by point into the storage system.
. 2 It is also known from French Patent Specification No. 2,032,334 to provide a pattern control system for a knitting machine which includes a store for a limited number of pattern elements in the form of coded information, in which information is entered into a temporary store by the actuation of keys while a display of the stored information is exhibited to the operator. The original design is then directly compared with the display and the corrected information is then transferred piecemeal into a computer.
SUMMARY OF THE INVENTION It is an object of the invention to provide pattern control means wherein correspondence between an original pattern and pattern information stored in a memory device may be determined immediately upon entry of the information into the memory.
It is a further object of the invention to provide pattern control means whereby pattern information entered into a memory device containing all the pattern information necessary for the production of a textile article at the same time as a display representing the relevant portion of the pattern information is provided to the operator.
One embodiment of the invention comprises a pattern control system including a television camera having a pickup tube viewing an original pattern representation to develop a video signal representative thereof and scan generators for said pickup tube, together with memory means containing stored information representative of the pattern. The system further comprises display means including a television picture tube having a viewing screen and scan generators for the pickup tube, a synchronizing signal generator producing line and field synchronizing signals which are applied to the camera and to the display means to control the scanning thereof. The system also comprises access means sequentially withdrawing pattern information from the memory means and applying the information to the display means to produce a display representative of the stored information. The system additionally comprises means applying the camera video signal to the cathode ray picture tube to produce a monochrome image of the original pattern representation.
Another embodiment of the invention comprises a pattern control system for entering pattern element information into a memory device, said system comprising display means including a scanned television picture tube, a memory means operable to store said pattern information; access means sequentially withdrawing information from said memory means to develop individual control signals representative of display elements corresponding to the information; means applying said control signals to said picture tube to produce an information display representative of the stored pattern information; keyboard encoder means responsive to selective actuation of a plurality of data keys to develop coded signals representative of different pattern information, keyboard address means developing numerical address signals denotive of a location within said memory means; and means applying said coded signals and said address signals to said memory means so as to insert pattern representative signals in the memory means at the location represented by the address. I
An embodiment of a system in accordance with the 5 invention will be described by way of example with reference to the accompanying drawings, of which:
FIG. 1 is a pictorial diagram showing the appearance of illustrative components of one embodiment of a pattern control system in accordance with the invention;
FIG. 2 is a block schematic diagram illustrating the interconnections of the components of the pattern control system of FIG. 1;
FIG. 3 is a pictorial diagram showing that the system according to the invention produces a display denotive of an original pattern representation and of pattern information entered into a memory;
FIG. 4 is a block circuit diagram of display shift register circuitry used in the embodiment;
FIG. 5 is a block schematic diagram illustrating the arrangement of certain display controls in the embodimerit;
FIG. 6 is a circuit diagram, partly in block form, of display switching and mixing circuits used in the embodiment;
FIG. 7 is a simplified logic diagram of display address circuitry used in the embodiment;
FIG. 8 is a simplified logic diagram of keyboard oncoder circuitry used in the embodiment;
FIG. 9 is a logic diagram of keyboard address circuitry used in the embodiment; and
FIG. 10 is a simplified logic diagram of marker signal generating circuitry used in the embodiment.
FIG. 1 shows the apparatus forming an embodiment of a pattern control system in accordance with the invention. A television camera 1 is arranged to view an artists design or other original pattern representation 2, which is supported upon an easel 3. The work support 3a of the easel is supported so that it can be moved in two perpendicular directions in its own plane, as indicated by arrows 3b and 3c. Camera 1 is advantageously supported, as shown, by a camera stand 4 movably mounted on rails 4a to permit the camera to be moved along an axis 4b perpendicular to the plane of movement of easel 3. Alternative arrangements apparent to those skilled in the art may be used to permit appropriate relative movement of camera 1 and pattern representation 2. Camera 1 is connected by a cable la to a control unit 7 upon which and electrically connected thereto is a display unit 5 including a television display tube 6. Alternative positions for display unit 5 may be adopted if preferred.
It is very desirable in the present system that the television camera 1 shall provide a video signal capable of providing a display of high geometrical accuracy. It is found advantageous for this purpose to employ an electrostatically scanned pickup tube, for this choice enables the required scanning accuracy to be obtained more conveniently than when a magnetically scanned pickup tube is employed.
Control unit 7 is provided with a keyboard portion 8 having a control panel 100 and a keyboard 121, the purposes of which are described later in relation to FIG. 2. If desired, the keyboard portion 8 may be placed remotely from the control unit proper and connected thereto over suitable wiring. Control unit 7 is also connected to a memory unit 10, in which pattern information is stored. The stored information is used to provide a display on display unit 5 representative of the stored information and may additionally or alterna tively be fed out by way ofa cable 1 l to the control unit 9 of a circular knitting machine (not further shown) of known, electrically controllable kind.
The memory unit 10 may conveniently include a known memory device using a matrix of magnetic core stores to receive, retain and reproduce coded pattern information as desired. Other known forms of memory device 9 may however be used as convenient. Many such memory devices and appropriate means for reading-in and reading-out the stored information have long been known in the data processing art and are not considered to require further description.
The pattern information stored in memory unit 10 may be additionally be used, if so desired, to control a tape punch system housed in the control unit 7 and arranged to produce a punched tape 12 carrying patternrepresentative information corresponding with that stored in the memory, this information being arranged in any required code or sequence, but typically providing a tape which may be used in turn to control the punching of control discs for disc-controlled knitting machines of known type, or a tape which may itself be used to control a knitting machine.
FIG. 2 shows a block schematic diagram of one embodiment of a system in accordance with FIG. 1. Control unit 7 contains a synchronizing signal generator 14 of known type which provides conventional television line and field synchronizing signals over leads 14a to control a line and field scan generator unit 1k in camera 1, over leads 14b to control a line and field scan generator unit 5a in display unit 5 and which provides line and field synchronizing signals over respective lines 14c, 14d to control unit 7. The television camera 1 includes a pickup tube If to which line and field deflection signals are applied from the respective line and field scan generators included in scan generator unit 1k. Display unit 5 includes a colour picture tube 6 having deflection means 60 to which line and field deflection signals are applied from respective line and field scan generators contained in scan generator unit 5a. Video signals representative of the original pattern representation are fed from camera 1 over a lead 15 to a switching and mixing circuit 99 controlled by a control panel 100. information signals withdrawn from memory .10 are passed to the switching and mixing circuit 99 by way of leads 57, while signals representing pattern information are fed into the memory 10 from a keyboard unit 120, controlled by a keyboard 121, over leads 17.
Display controlling signals are applied from switching and mixing circuit 99 to display unit 5 by way of leads 19, where they are applied to control the intensity of the electron beams produced by the red, blue and green guns 6a, 6b and 6c of colour television picture tube 6. Finally, signals withdrawn from memory 9 by way of memory control unit 10 may be applied over a control cable 11 to control the operation of a knitting machine.
The camera 1 views the original pattern representation 2 and the video signal which is thus developed is used to produce on the screen of cathode ray tube 6 of display unit 5 a corresponding half-tone image, Existing cathode ray picture tubes of the most convenient size cannot be used to display a pattern containing more than some 152 X 96 pattern information units, stitches in the present embodiment. With a pattern containing more than this number of pattern elements, therefore, the camera is positioned by means of the traveling camera stand 4, and the pattern representation is positioned in its own plane by adjustment of easel 3, so that the camera views only a portion of the pattern, as shown in FIG. 3, where it will be observed that the field of view of the camera, denoted by broken line 13, encompasses only some one-quarter of the whole pattern, so that this portion only of the design is displayed as a half-tone image upon cathode ray tube 6.
In a system according to the invention there is superimposed upon the half-tone image of the pattern which is produced on the screen of display cathode ray tube 6 a display indicative of the individual elements of pattern information which have been entered in memory unit 9 for use in the direct or indirect control of a knitting machine. If display cathode ray tube 6 is a monochrome display tube the different kinds of information entered in the memory may be displayed by symbols of different geometric form appropriately positioned on the screen of the display tube.
It is, however, preferred that display tube 6 shall be a colour television display tube and that the different kinds of pattern information shall be displayed by respectively differently coloured elements in the display. It is not necessary that the displayed elements shall be of the same colours as the pattern elements produced in a knitted particle in response to the stored pattern information, though it is usually most convenient that this shall be so.
The display produced by the pattern information stored in the memory unit is illustrated in the lower part of the display shown in FIG. 2 by the symbols X, 0 and S, representing the symbols or distinct colour displays produced by different information codes in the memory, superimposed upon the shaded display areas representing the monochrome image of the pattern representation, the different portions of which are denoted by different shadings. It should be noted that for the sake of clarity in illustration a few symbols only are shown and that these are much larger than they would be in practice, in relation to the size of the display.
Although the original pattern representation 2 will usually be coloured, it is most economical to arrange that the displayed pattern portion appears in monochrome, the colours of the original appearing as varying half-tones between black and white. It will sometimes be desirable to dispose a colour filter between the original pattern representation 2 and the camera 1, in order that all the pattern colours shall be represented in the monochrome image by readily distinguishable half-tone values. FIG. 3 shows how the camera 1 may be provided with a support means lb arranged to accept interchangeable colour filter members, such as filter 1c.
However, it may in some cases be found desirable to provide a coloured display of the original pattern representation, and it is then necessary to provide a colour television camera and appropriate known associated circuitry to form television camera 1.
It is assumed in the following description that television camera 1 and display unit 5 employ a standard scanning raster as used in commercial broadcast apparatus, as this choice permits many commercially available parts to be used, especially the display unit. Other scanning standards may be used if preferred without departing from the scope of the invention as defined by the claims.
The area of the original pattern representation appearing upon the display screen may be adjusted by varying the distance between the camera and the design, by movement of the camera stand 4 upon the rails 4a (FIG. 1). Alternatively or in addition the camera may include a variable magnification lens with constant focal distances, that is a zoom lens 1d, of which the magnification may be adjusted by means of a manual control 1e. The usual requirement is to adjust the camera or lens so that a specific area of the original design representation corresponds with a predetermined number of courses and wales of a display which is produced on the tube screen as later described under the control of the information stored in the memory unit. If the aspect ratio of the original pattern representation differs from that of the information display this will obviously be impossible, and a means for adjusting the aspect ratio of the pattern image is therefore provided. When setting-up the system prior to entering pattern information into the memory, the distance of the camera from the original pattern representation is first adjusted until the width of the reproduced monochrome image of the pattern representation is the same as the width of the information display derived from the information stored in the memory. An image height control, usually most conveniently provided on the camera itself, is then adjusted to vary the amplitude of the camera scan as is described below in relation to FIG. 5.
It is in practice inconvenient to provide a memory from which information may be withdrawn at the rate at which it must be made available to control a cathode ray tube display using a standard television raster. Information withdrawn from the memory and representing one pattern line is therefore entered into one of two circulating registers and meanwhile information representing the adjacent pattern line, which has previously been entered into the other circulating register, is repeatedly withdrawn from that other register to control the display.
A block diagram illustrating this part of the system is shown in FIG. 4. For simplicity, the system is described only as set up for 6 raster lines per pattern row and for a display width of 128 pattern elements. Because display unit 5 uses standard interlaced scanning, only three raster lines are consecutively provided with the same information during each field scanned.
Each of two shift registers 51 and 52 is arranged to provide four storage channels, which are used to store sequences of 3-bit codes which are withdrawn from the memory and the fourth channel is used to receive a marker bit, the purpose of which is described later. Each channel has a maximum capacity of 160 bits; these may be switchable to provide different effective storage capacities, as may be convenient. In the following description a total storage of 128 bits per channel is assumed. By means of switching units 53 and 54 the shift registers are used alternately, one being filled with information from the memory, whilst the other is recirculating and presenting its stored information to the display by way of a decoder 55, which causes the pattern information contained in the 3-bit code groups to energise a selected one of five different display-control lines, or none of them.
When one of the shifting registers 51, 52 is operating in the recirculating mode it is clocked by the output of a pulse burst generator 56, which conveniently takes the form of a gated multivibrator. The line synch. pulses from the synch. generator 14 (FIG. 2) are applied over a line to the pulse burst generator 56, this latter produces a burst of pulses equal in number to the number of bits stored in each channel of the register, in the present instance, 128 pulses, which produces a complete recirculation of the information stored in the register. The timing of the generated pulse burst in relation to the initiating pulse on line 14c is determined by a potential received over a line 30 from the circuits described later with reference to FIG. 5. The 128 pulses must occur within a time not greater than that taken for the electron beam of the display cathode ray tube 6 to scan one raster line on the screen. This requires a fast clock frequency appropriate to the number of lines in the raster.
That one of the shift registers 51 and 52 which is at any time receiving data from memory 9 over lines 16 is clocked by the output of a Data Input Clock generator 58. This generator also produces a burst of 128 pulses, but at a slow clock speed which is compatible with the maximum output speed of the memory. In order to ensure that the information in the register feeding the display is recirculated the correct number oftimes a Line Counter circuit 59 is provided, to which the line synch. signals received over line 14c are provided and which provides an output pulse on a line 60 only when the appropriate number of line pulses (three in the present case) has been received. The input clock generator 58 provides a slow clock signal over a line 61 to the shift register 51 or 52 which is receiving information, over a line 62 to the memory, where they constitute read/restore cycle initiating pulses controlling read-out of stored information from the memory in known manner and over a line 63 to the Display Address circuit described below with reference to FIG. 7.
Pulses provided by line counter 59 on line 60 are also applied to switching units 53 and 54 to control the change-over from one to the other of shifting registers 51 and 52, these being alternately connected to receive and to supply information, as has been said. As the information-supplying register is circulated the successive code groups are applied to decoder 55, with the result that for each code an output is applied to one of the five output lines 55a 55c of the decoder, or to none of them if the code represents a space; additionally if a marker bit is present in the line being circulated it is fed out over a line 64 to the control panel circuitry for display.
In the system as described above the elements of the display corresponding to the information in the memory are superimposed upon the image of the original pattern representation, both being simultaneously visible on the screen. It may be preferred that the display elements representing the stored information shall replace the pattern image. This effect may be produced by providing an OR gate 85 (FIG. 6) responding to any output signal from decoder 55 received over lines 55a-55e to develop an inhibiting signal which is applied to a gate 86 introduced into the line which carries the video signal from the camera 1 to the display unit by way of the video amplifier 80. The presence of any display signal thus suppresses the video signal appropriate to the corresponding position on the display screen.
The necessity for providing an adjustment of the raster height used in the camera has already been explained. This height adjustment may be effected by means of a potentiometer 24 (FIG. 5) which may most conveniently be placed on the camera 1, though it can if required be placed elsewhere. Potentiometer 24 is connected across a direct-voltage source represented only by terminals and and the potential selected by the setting of its slider 24a is applied in known manner to control the amplitude of the deflection voltage produced by a scan generator 25 supplying sawtooth voltages to the vertical deflection plates lg, 1h of the camera pickup tube If.
It is advantageous to provide means for fine adjustment of the position of the information display in relation to the monochrome pattern image, and for adjustment of the orthogonality of the information display, as will now be described in relation to FIG. 5. Fine adjustment of the vertical position of the information display is effected by means of an UP/DOWN control 26 on the keyboard 121 (FIGS. 2 and 5). Control 26 adjusts the value of a variable resistor which is connected over a line 44 to form the timing resistor of a variable-delay flip-flop 45 (FIG. 4). Flip-flop 45 is fired by field synchronizing impulses received over line 14d from synchronizing signal generator 14 (FIG. 2) and yields on a line 46 variably delayed inhibiting signals which are applied to a gate 47 by way of which line synchronizing pulses received over a line 14c from the synchronizing signal generator 14 (FIG. 2) are fed to control the operation of the burst pulse generator 56, as later described. Gate 47 thus prevents line synchronizing pulses from triggering burst pulse generator 46 until a time after the commencement of the field period of the display raster which is determined by the setting of control 26.
The gated line synchronizing pulses provided on line 47a by gate 47 are applied to fire a further variabledelay flip-flop 48 providing drive signals to the Brust Pulse Generator 56 of which the operation has already been described. The delay of flip-flop 48 is controlled by circuit arrangements shown in FIG. 5, to which flipflop 48 is connected by way of a lead 30. As shown in FIG. 5, line 30 is connected to the slider 29a of a variable resistor 29, which is connected to ground by way of the parallel combination ofa resistor 31 and the controlled path of a transistor 32. The effective value of the timing resistance for flip-flop 48 thus depends upon the setting of variable resistor 29 and upon the potential applied to the gate of transistor 32. This gate potential is variable throughout the field scan period, as will now be described.
Direct voltage from a source represented only by a terminal and an earth symbol is applied to a voltage stabilizer circuit formed by an NPN transistor 33, the base of which is held at a fixed potential above ground by being returned to the tapping of the series combination ofa resistor 34 and a pair of Zener diodes 35a, 35b, the series combination being connected across the supply. The transistor collector is returned to the positive supply terminal and its emitter provides a stabilized direct voltage to the parallel combination of a capacitor 36 and a voltage divider chain including a potentiometer 37 and range-limiting resistors 38a, 38b. The potential appearing at the slider 37b of potentiometer 37 is fed over a resistor 38!) to one input of an amplifier 39, the other input of which is grounded. Amplifier 39 is provided with a feedback capacitor 40 and thus acts as an integrator, developing an output voltage increasing proportionally with time. At each field scan a pulse is received over a line 140 which turns on a transistor 42 to discharge capacitor 40 through a resistor 43 to return the amplifier output voltage to zero. The amplifier output voltage is applied to the gate of transistor 32, which thus offers a linearly decreasing resistance dur ing the field scan period. The amount of change is determined by the setting of potentiometer 37, which thus forms an ORTHOGONALITY CONTROL determining the difference in timing between successively displayed lines of information derived from the memory.
In FIG. 6 it will be seen that the five output lines 55a-55c of decoder 55 and the marker signal line 64 all pass through an Inhibit circuit controlled by a signal which is formed by combining the delayed line synch. pulse from flip-flop 48 (FIG. 4) which is used to trigger the burst pulse generator 56 with a signal provided over a line 56b by burst pulse generator 56 when this is quiescent. These two signals are combined in an OR gate 49 whence they are fed over a line 70a'to the Inhibit circuit 70, thus allowing the outputs of decoder 56 on lines 56a 56e to become effective only when the shift register 51 or 52 is actually recirculating. When the inhibit circuit permits the signal on each decoder output line 55a-e controls a respective switching unit 71A 71E. The internal arrangements of switching units 71A 71E are identical, so that unit 71A only is shown in detail. Each unit contains three semiconductor switches of any suitable type. For the sake of convenience these are illustrated as being n-p-n transistors 72a, 72b, 72c, the bases of all three of which are supplied from the decoder output line 55a with a potential making the transistor operative when that output line is selected. When operative, transistors 72ac connect the potentials selected by three potentiometers 73a, 73b, 730 to respective common lines 74, 75, 76. Potentiometers 73a 730 are led to a Blister switch 101 by which they normally receive the potential selected by an Intensity potentiometer 102 connected across a direct voltage supply represented only by terminals and If the switch 101 is actuated, when the three potentiometers of the group receive the potential selected by a Blister Intensity potentiometer 103 connected across the same supply. The three potentiometers 72a-c and the corresponding groups of potentiometers in the other units, are used to control the respective RED,
BLUE and GREEN components of the display element produced then the respective decoder output line is energized. The lines 74-76 conduct the elected potentials to first inputs of respective video amplifiers 77, 78, 79, of which the outputs are taken to control the intensity of the electron beam of a respective gun in the cathode ray display tube 6. To the second input of each of video amplifiers 77-79 is applied an appropriate proportion of the output of a video amplifier 80, to the input of which the video signal developed by camera 1 is applied at a level determined by a Monochrome Intensity control potentiometer 104. The signal proportions applied to the second input of each of video amplifiers 77-79 are fixed by a resistance network 81 including individual voltage dividers 81a, 81b and 81c. The signal proportions are conveniently so fixed that for full intensity a white spot is traced on the screen of cathode ray tube 6.
To a seocnd input of video amplifier 80 is applied a marker signal which is received over a line 64 from the circulating register and is applied to the gate of a transistor 82 having its controlled path connected between the second input of amplifier 80 and a pulsed voltage supply obtained from a multivibrator 83, to which the transistor is connected by way of a switch 84 allowing the marker display to be discontinued when desired.
In order to display indications representing information stored in the memory, it is necessary to withdraw this information from the memory. For this purpose it is required that the address of each memory position containing information relating to the pattern field which is to be displayed shall be generated in turn and applied to the memory. This operation is effected by the course and wale address generators represented schematically in FIG. 7, the two numbers generated by which are combined to form a single location address which is fed to the memory.
Each 3 bit word is addressed using an 8 bit binary number equal to actual wale number and an 8 bit binary number equal to actual course number these numbers being combined to form the total 16 bit address. The stitches may therefore be said to be stored in visual order. The information thus withdrawn from the memory is fed over lines 57 to the shifting registers in the control unit which have already been described in relation to FIG. 5.
The addresses to be applied to the memory are developed by the identically operating wale and course address generators 140 and 150 shown in FIG. 7. The wale address generator 140 includes a wale counter 141 which is an up/down counter with facilities for parallel insertion. The 8 bit binary output of this counter is connected to the memory 9 by way of lines 17a and forms one half of the address. The counter receives batches of 128 pulses over line 63 from the data input clock 58 (FIG. whenever information is to be read out from the memory. Counter 141 will normally count upwards so that its binary output increases sequentially, thus withdrawing from the memory in turn all of the 128 information codes corresponding to one line of the pattern to be displayed. This information is fed out from the output register of the memory over lines 57 to the shift register 51 or 52 in the control unit, whence it is withdrawn as already described to control the display. The output of wale counter 141 is also applied to a comparator 142, in which it is compared with a number representing the required width of display, this second number being developed by a decimal-binary converter which receives as its input the decimal nubmer set up by a three-digit SET WIDTH switch 107. When the two compared numbers coincide, the main counter is reset to zero over a line 144. This causes the stitch sequence displayed across the screen to repeat at the set pattern-width intervals.
If a wale Mirror Repeat has been selected by actuating a Mirror switch 109, when the counter 141 reaches a predetermined number it recounts that number once and then counts sequentially downwards until it reaches zero, thus again withdrawing the same information from the memory, but this time in the reverse order. After repeating the zero count once, the counter then counts sequentially upwards again to extract either the next line of information, or the same information once again if a multiple repeat is required by the set width of pattern.
The Wale Counter is cleared and restarted by a signal over line 60 from the line pulse counter 59 (FIG. 4). This pulse occurs at the end of each displayed line of stitches. It is usually convenient to arrange that the return to its initial state of count of the wale counter 141, when the set pattern width has been reached, shall be accompanied by a corresponding change in the course number, so that further information will be entered in the adjacent pattern line. The line return signal which appears on line 144 may therefore be applied over a switch 111 to deduct one from the course number in counter 151, causing subsequent data key operation to introduce codes into the next higher line in the display.
In order that the displayed information may be taken from any desired portion of the memory, the wale address circuitry includes a horizontal shift counter 145, which also is an up/down counter and is driven by trains of pulses repeated at a rate of some 8 Hz, which are typically generated by a shift generator 146 which counts field synch. pulses and delivers a shift drive pulse for every three field pulses and are applied either to the up or to the down input of shift counter by actuation of a respective Right-Shift key 147 or a Left- Shift key 148. A further Fast key 149, when actuated, increases the repetition rate of shift generator 146 to 25 Hz. The shift generator 146 may be a multivibrator of which a coupling time-constant is changed by actuation of Fast key 149.
Before each count of 128 on Wale Counter 141 commences, the output of shift counter 145 is introduced into the Wale Counter. This initial count determines the position in the memory at which the sequential addressing of memory locations by the output of the wale counter will commence, that is, the position of the lefthand edge of the pattern portion which will be displayed on the screen. Thus the pattern display starts from a position determined by the actuation of the pattern shift controls and appears to move to the left or to the right on the screen when one of these is actuated.
The Course address circuit 150 is almost identical with the Wale address circuit, but normally operates at a lower speed. Moreover, the signal applied to course counter 151 reduces the number in the counter, because successive courses in the display are required to appear upwards from the bottom of the screen.
The elements of this circuit which have functions exactly corresponding with elements of circuits 140 are denoted by reference numerals ten higher than those of the like elements in circuit 140. The number in the Course counter 151, however, is changed only at the end of each line of stitches and to this end is driven by pulses received over line 60 from the line counter 59 of HG. 4, while it is cleared and re-started by field synchronizing signals received over a line 14c from the synch. generator 14 of FIG. 2. A separate shift generator is not needed, the signals from generator 146 are applied by way of switches 157 or 158 to the up or down inputs of counter 155 to produce upward or downward vertical displacement of the displayed pattern portions.
The system as so far described operates to display on the display unit 5 a monochrome image of an original pattern representation, upon which is superimposed a preferably coloured display representing pattern information stored in the memory unit. If upon commencing operations there is no pattern information contained in the memory unit, then the pattern image will appear in monochrome without any superimposed display. lf pattern information is now progressively entered into the memory, it will immediately appear on the display screen, and the correspondence between the pattern image and the stored information may be discerned.
in accordance with a preferred feature of the invention, therefore, means are provided for inserting pattern information into the memory unit at a position which may be selected at will and which is preferably denoted by an indication on the display. In the system described in relation to the accompanying drawings an operator viewing the monochrome pattern image produced on the screen of display cathode ray tube 6 may proceed to enter corresponding pattern information in an empty memory unit by actuating corresponding ones of a plurality of data keys 122 provided on a keyboard 120 of control unit 7. When actuated, each of the keys 122 causes a respective unique 3-bit code to be entered into the accessible keyboard address in the memory 9, which code may represent a particular colour or type of switch and will consequently give rise to an appropriately coloured element in the display. Actuation of a key 122 normally also produces a change of keyboard address by one element. Conveniently, the first pattern element entered in the memory appears at one end of a line and, because the bottom of a pattern is usually the first portion to be knitted, it will be convenient to arrange that the first pattern indication appears at the bottom, left-hand corner of the display.
In the present embodiment information is withdrawn from the memory during the scanning period of each display and inserted into the memory during the flyback periods of the scan. Other time division methods may be used if preferred.
Because information is required to be withdrawn from the memory during the whole of each field scanning period, though not during the fly-back periods, the information to be inserted in the memory, denoted by the actuation of the data keys, must be stored until the end ofa field scan and then fed into the memory in the appropriate locations. These operations are effected by the Keyboard Encoder and Address circuits described below in relation to FIGS. 8 and 9.
FIG. 8 shows the keyboard encoder circuit 160; in this Figure. those circuit elements which are identically repeated are shown in full only once. The keying circuit, which is repeated for each of the five data keys and for the space bar (here referred to as Keys Nos. 1 6) is first described. The No. 1 key when actuated applies an enabling signal by way of a Schmidt NAND gate 162 to a flip-flop 163, which generates an output pulse of 400 nS duration. This pulse is applied to one input of an 8-input NAND gate 164. The output signal of flip-flop 163 is also applied by way of a NOR gate 165 and NAND gate 166 to develop a signal on a line 167. Signals are similarly developed on line 167 when any other one of keys Nos. 1 6 is actuated. The signal on line 167 thus denotes that a key has been actuated and is employed to prevent other circuits responding to spurious signals which may arise when a key has not been actuated, and also as a preparatory signal to enable a buffer store which is described later.
The output signal of NAND gate 164 is applied by way of a NOR gate 168 to a further flip-flop 169 which generates a 476 nS pulse. This pulse is returned to an input of gate 164 as a lock-out pulse to prevent the circuit responding a second time if the key should still be held actuated at the end of the first pulse from flip-flop 163. The output of the eight-input gate 164 is also fed over a line 170 to each of the eight-input gates in the other five keying circuits, to act as a lock-out signal, and is additionally directed over a line 171 to the coding circuit 172 described below. Gate 164 itself receives a lock-out signal over one of the lines 173 from the output of the eight-input gate in each of the other keying circuits, whenever the respective key is actuated.
The keying signals provided on line 171 and on corresponding lines 174 from the other keying circuits are each applied to a different combination of three NAND gates 175, 176, 177 in the coding circuit 172, so that output signals appear at a unique combination of the three gates in response to actuation of each of the six keys. In the present embodiment the codes produced by actuation of the keys are as shown below, but these may be altered as desired by reconnection of the key outputs to the gates.
Key 175 176 177 1 x 6 x x x Whenever a signal appears at the output of any one of gates 175 177 a NOR gate 178 connected to all of the outputs itself provides an output signal to a flip-flop 179 in a first buffer store stage 180. Stage 180 includes a Quad D-type flip-flop 181 into which are fed the outputs of gates 175 177 and also the preparatory signal on line 167. This latter signal is also applied to a NAND gate 182 which ensures that the output signal of flipflop 179 can pass to clock store flip-flop 181 only when a preparatory signal is present on line 167. When buffer flip-flop 181 is clocked by the output from flip-flop 179 the signals applied to its four inputs appear on corresponding output lines 183 and are applied to a succeeding buffer store stage 184. The code output signals are also applied to a NOR gate 185 yielding a drive signal to buffer stage 184 whenever a signal appears on any output line of stage 180. The arrangement of stage 184 and of a third succeeding buffer store stage 186 are identical with those of stage 180. The signals appearing on the output lines 187 of third buffer store stage 186 are fed to the memory 9 to be entered in the currently accessible address. Output signals from NOR gate 178,
from NOR gate 185 in the first buffer store stage 180 and from the corresponding NOR gates in second and third buffer store stages 184 and 186 are applied to a NAND stage yielding a NO DATA IN STORE signal on a line 189 to the address circuit (FIG. 9) when all the store stages are empty and the on coder output is zero. A signal which is developed by the NOR gate of third buffer store stage 186 when any output signal is present is inverted in an inverter 190 and applied to a NAND gate 191 which also receives the preparatory output signal from stage 186 and which yields a NEW DATA AVAILABLE signal to the memory on a line 192.
If the same or other keys are pressed twice more, then corresponding codes will be entered into the second and the first buffer store stages 184, 180. When the information on output lines 187 has been entered into the memory in known manner which does not require description a DATA TRANSFER COMPLETE signal is provided by the memory on a line 193 and applied to a flip-flop 194 yielding a 105 nS pulse over a line 195 to clear the third buffer stage 186. When all lines of the stage carry logical Os the output signal from the NOR gate tires the flip-flop which clocks the code from the output of the second stage 184 to the output of the third stage 186. This operation causes firing of the drive flip-flop of stage 180 also, in a similar manner, so that a code at the output of the first buffer store stage 180 is transferred to the second stage 184. Thus as soon as a code is read by the memory it is cleared from the buffer store and the next code is automatically clocked into its place.
When flip-flop 194 is fired by the DATA TRANS- FER COMPLETE signal on line 193 it will if an AUTO/MANUAL switch 196 is setto AUTO, pass a STEP ADDRESS ON ONE signal on to a line 197 to control the keyboard address circuit described below in relation to FIG. 9.
A Repeat key 198 may be pressed simultaneously with any one of the Data keys. When actuated, this key allows pulse signals from 21 Repeat Generator 199 to recycle the respective keying circuit flip-flop as long as both the Repeat and Data keys are actuated. The repeat signal is also fed out over a line 200 to the address circuits described below in relation to FIG. 9 where they are used as there described to produce repetitive movement of the Marker display.
An Inhibit key 300 applies a signal to NAND gate 162 and another signal, inverted by an inverter 301, by way of a line 302 to an input of the eight-input NAND gate of the keying circuits, to prevent inadvertent actuation of the keys producing a change in the data in the memory during periods in which operation of the system is interrupted.
The keyboard addressing circuitry is shown in FIG. 9. It comprises a Wale Counter 20] and a Course counter 202, the outputs of which are fed over cables 203, 204 to the wale and course address circuits of the memory 9. Each counter provides an eight-bit address to the memory. The outputs from each counter are monitored by a respective logic circuit 205, 206 which detects the presence of an all 's output from the respective counter and when this is present applies an inhibiting signal to a respective gate 207, 208 which locks out the Down" input to that counter and thus prevents it being made to count down through zero to provide a fixed datum position for the display.
The addressing circuits are chiefly controlled by four Marker keys 211, 212, 213 and 214 which produce movement of the keyboard address and therefore of the displayed marker, in the four directions RIGHT, LEFT, UP and DOWN, respectively. When key 211 is actuated it applies a logic signal by way of a NAND gate 215 to initiate a flip-flop 216, which in turn applies a signal by way of a NAND gate 217 and an inverter 218 to the UP input of wale counter 201, thus producing a shift of the marker to the right in the display. The output signal from gate 215 is also applied to lock out a gate 214 through which the logic signal from the LEFT key 212 is applied to initiate a flip-flop 220 from which a signal is applied by way of lockout gate 207 to the DOWN input of the wale counter 201. The output signal of gate 214 is applied to lock-out gate 215, so that inadvertent actuation of both keys simultaneously does not produce incorrect operation of the system.
UP key 213 when actuated provides a logic signal to a gate 221, the output signal of which initiates a flipflop 222, the signal from which is applied by way of a gate 223 and an inverter 224 to the UP input of Course Counter 202. The DOWN key 214 supplies a logic signal to a gate 225, of which the output initiates a flipflop 226, of which the output is applied by way of lockout gate 208 to the Down input of the Course Counter 202. The outputs of each of gates 221, 225 lock-out the other gate to prevent operating errors. The keys thus far described permit the addresses generated in the counters 201, 202 to be increased or reduced and so would suffice to obtain access to any address in the memory. To expedite operation of the system, facilitates for obtaining immediate return to a predetermined setting of one or both counters, as desired, may be provided. To this end, a set of D-type flip-flops is provided to store the number appearing on the output lines of each counter when a respective Wale Tab key or Course Tab key is actuated. Actuation of the Wale Tab key 228 applies an initiating signal to a flip-flop 229, the output of which clocks the WALE TAB set of flip-flops shown as a single unit 230. These flip-flops receive the counter output signals at their inputs and, when clocked, apply the signals on their inputs to reset the respective counter stages to that number. To establish a position to which the counter may be returned from any other position, therefore, the counter is set by actuation of the marker controls to the appropriate position and the respective TAB key is actuated. This enters into the D-type flip-flops the number to which the counter is then set, and clocking of the counter load line at any layer time will reset the counter to that number. A similar operation occurs on actuation of the Course TAB key 231, which actuates a flip-flop 232 to clock the load lines of the COURSE counter 202.
Return of the marker to a predetermined position may be effected in either of two ways; by depressing the Line Return key 234 or the Block Return key 235. Actuation of the Line Return key 234 passes a logic signal through a gate 236 to actuate a flip-flop 237. The output signal of gate 236 is applied to inhibit a gate 238 in the Block Return circuit next to be described. The output signal of flip-flop 237 applies an inhibiting signal to gates 239, 240 inhibiting the Load and Clear lines of the Course Counter 202. Finally, the output signal from flip-flop 237 is applied by way of gate 223 to the Up input of the Course Counter 202, thus adding one to the number present in the counter, and also fires a further flip-flop 241, the output signal of which clears the Wale Counter 201 and also fires a third flip-flop 242 yielding an output which, is applied to a NAND gate 243 together with the output of flip-flop 241 after inversion in an inverter 244, so that the output of NAND gate 243 is inhibited. When flip-flop 241 returns to normal the output of gate 243 is applied to load the Wale counter 201 with the number then present in the output of the Wale Tab flip-flops. This number then appears on the address output lines.
Actuation of the Block Return key 235 produces an action generally similar to that of the Line Return key, but in this case flip-flop 237 is not tired, so that the Course Count remains unchanged and the clear and load lines of the course counter are not inhibited. Thus both counters are cleared and then loaded with the predetermined numbers set into the respective TAB stores, as described above.
The NO DATA IN STORE signal developed in the Keyboard encoder described with reference to FIG. 8 is received on line 189 and is applied to inhibit all the keys controlling the address until all information from the keyboard has been entered into the store. The STEP ADDRESS signal from the keyboard is received on line 197 and is applied to gate 217 to add one to the Wale count.
When it is desired to change the address, i.e., to move the marker, by more than one stitch or course, then the appropriate Marker Key, 211-214 is actuated together with the Repeat key 198 adjacent the Data keys. A pulsed signal is then received over line 200 and causes repeated firing of the respective flip-flop to produce rapid movement of the marker in the desired direction.
The number representing actual address to which access is at any time available is shown to the operator numerically. Decoders 245, 246 connected to the output lines 203, 204 of counters 201 and 202 respectively control 3-digit displays 247 and 248 which show the present Wale and Course numbers.
To generate the marker signal which gives rise to the appearance of a pulsating white element in the display, the keyboard Wale and course addresses are continuously compared with the display wale and course addresses and a marker bit is inserted in the circulating register when both addresses coincide. The circuit arrangement is shown in FIG. 10. The Wale Display and Keyboard addresses appearing on line 17a of FIG. 7 and on lines 203, of FIG. 9 are applied to a comparator circuit 250 of known kind which yields an output signal on a line 251 only when the corresponding digits of the two addresses are identical in each case. This signal is applied to a Marker gate 252 and to a gate 253 which controls the lighting of a Wale Marker lamp 254. The lamp is lit whenever the marker address set by the keyboard is within the display in the Wale direction. The Course addresses for the display and the keyboard which appear on lines 17b of FIG. 7 and on line 204 of FIG. 9 are applied to a Course Comparator 255 yielding an output on a line 256 only when the compared address numbers are identical. The signal on line 256 controls a gate 257 to light a Course Marker lamp indicating that the marker address set by the keyboard is within the display in the Course Direction. When signals on lines 251 and 256 are applied simultaneously to marker gate 252 a signal will appear on line 259 to be inserted in the display as described with referenceto FIGS. 5 and 6. The purpose of the two Marker lamps is to indicate when the marker address is or is not present in the displayed area of the pattern information.
It will be understood that although an advantageous complete system has been described, the described means for superimposing a pattern information display representative of pattern information stored in a memory device upon an image of an original pattern representation may be used without providing the means for entering pattern information into the memory. Similarly, means for displaying pattern information contained in a memory and for entering pattern information into the memory may be employed without the provision of means for combining an image of an original pattern information with the display.
It will be seen that the pattern control system described above enables pattern information corresponding with an image of an original pattern representation to be very rapidly introduced into a memory while providing an immediate visual display of the information so entered for comparison with the image of the original pattern.
1. A pattern control system comprising a television camera including a pickup tube viewing an original pattern representation to develop a video signal representative thereof and scan generators for said pickup tube;
memory means containing pattern information storage locations represented by address numbers, whereby application of signals representative of said numbers to said memory means obtains access to said locations;
display means including a television picture tube having a viewing screen and scan generators for said picture tube;
synchronizing signal generator means producing line and field synchronizing signals;
circuit means applying said synchronizing signals to said scan generators of said television camera and of said display means to produce corresponding scans thereon;
means applying said video signals to said picture tube to develop an image of said pattern on said viewing screen;
access means operable to develop said address numbers thereby to withdraw said pattern information from said memory means as memory output signals;
display control means fed with said memory output signals to develop individual control signals representative of display elements corresponding to said information;
and combining means applying said control signals to said picture tube together with said video signals to produce thereon a display representative of said image and of said stored pattern information.
2. The system claimed in claim 1 and further including support means supporting said pattern representation in a plane and camera mounting means, said sup port means and mounting means together providing relative movement of said representation and said camera in two directions in said plane and along an axis perpendicular thereto.
3. The system claimed in claim 1 and further including adjustable support means supporting said pattern representation for movement in two directions in a plane, said camera having a variable magnification lens of constant focal distances.
4. The system claimed in claim 1 and further including variable amplification means whereby vertical defiection signals produced by said scan generator means are applied to said pickup tube and means controlling said variable amplification whereby to change the aspect ratio of said pattern image.
5. The system claimed in claim 1 wherein said pickup tube is an electrostatically deflected pickup tube.
6. The system claimed in claim 1 wherein said pickup tube is an electrostatically deflected pickup tube.
7. The system claimed in claim 1 wherein said television picture tube is a colour television picture tube, said system further including individual potentiometer means operable to adjust individually the colour of the said display element produced in response to the application of each of said control signals to said picture tube.
8. The system claimed in claim 7 wherein said television camera is a colour television camera developing colour television video signals and including circuit means whereby said colour television video signals are applied to said colour television picture tube to produce a coloured image of said pattern representation.
9. The system claimed in claim 7 and further including common potentiometer means connected in circuit with all said respective potentiometer means, whereby the intensity of all said display elements may be adjusted simultaneously.
10. The system claimed in claim 9 and further including individual switch means whereby any one of said respective potentiometer means may be disconnected from said common potentiometer means and connected to an additional potentiometer means permitting individual control of the intensity of the respective pattern indication.
11. The system claimed in claim 1 wherein said access means includes:
two shifting registers;
switching means operable to connect said shifting registers in alternation to receive information signals from said memory means and to supply information signals to control said display; first pulse generator means responsive to said line synchronizing signals to develop first pulse trains each including a predetermined number of pulses, said pulse train having a first repetition rate;
pulse counter means responsive to said line synchronizing pulses to develop a counter output pulse in response to each predetermined plurality of said synchronizing pulses;
second pulse generator means responsive to said counter pulses to develop second pulse trains each including said predetermined number of pulses, said second pulse train having a repetition rate equal to said first repetition rate divided by the number of said predetermined plurality;
first display address counter means holding a number denotive of part of the address of an information storage location in said memory means;
means applying said second pulse train to change the number in said first display address counter and to shift said shifting register connected to receive information signals from said memory means; means applying said display address number to said memory means to cause the development of information signals sequentially representative of information stored in said predetermined number of adjacent locations;
means applying said information signals developed by said memory to said shifting register connected to receive information signals;
means applying said plurality of first pulse trains to said shifting register connected to supply information signals to cause the repeated development of information signals stored therein;
and means applying said repeatedly developed information signals to control said display means to develop said information display.
12. The system claimed in claim 11 and including adjustable signal delay means having a signal delay adjustable by an applied voltage, means including said signal delay means for applying said line synchronizing pulses to said first pulse generator, voltage divider means developing an adjustable voltage and circuit means applying said adjustable voltage to said signal delay means whereby to provide lateral adjustment of the position of said display.
13. The system claimed in claim 12 and further including adjustable further signal delay means adjustable by an applied voltage, gate means controlling the application of said line synchronizing signals to said first pulse generator means, means including said further signal delay means for applying said field synchronizing signals to said gate means, and-potentiometer means providing a further adjustable voltage to control said further delay means whereby to provide vertical adjustment of the position of said display.
14. The system claimed in claim 12 wherein said voltage divider means voltage-variable resistance means, and further including ramp voltage generator means actuated by said field synchronizing pulses to develop a ramp voltage of adjustable amplitude repetitive at field frequency, and circuit means applying said ramp voltage to control the resistance of said variable resistance means whereby to provide adjustment for the orthogonality of said display.
15. The system claimed in claim 11 and including a second address counter holding a second address number denotive of the remainder of the address of said location;
presettable switch means adjustable to establish a further predetermined number:
comparator means responsive to said first address number and to said further predetermined number to develop a return signal when said numbers are identical; means applying said return signal to restore said first address counter to a predetermined state of count;
means applying said return signal also to said second address counter to change said second address number; and
means applying said second address number to said memory means to control the development of said information signals.
16. The system claimed in claim 15 and further including:
number signal storage means;
transfer means operable to apply signals representative of the number in a said address counter to said storage means to be stored therein;
resetting means operable to reset said address counter with signals from said storage means to said stored number.
17. The system claimed in claim wherein said address counter means contains means operable by said return signal to reverse the direction of count of said counter and means operating in response to said counter reaching a zero state of count to again reverse its direction of counting.
18. The system claimed in claim 15 and further including:
signal generator means generating repetitive signals; first shift key means operable to apply said repetitive signals to said first display address counter means to change the number therein in a first sense;
second key means operable to apply said repetitive signals to said first address counter means to change the number therein in the sense opposite to said first sense;
third key means operable to apply said repetitive signals to said second address counter means to change the number therein in said first sense; and fourth key means operable to apply said repetitive signals to said second address counter means to change the number therein in said opposite sense.
19. The system claimed in claim 18 and including also a further key means operable to change the repetition rate of said repetitive signals. I
20. The system claimed in claim 1 and further including keyboard means operable to introduce any one of a plurality of predetermined pattern-representative coded signals into any selected location in said memory means, said keyboard means comprising:
keyboard encoder means responsive to the actuation of any one of a plurality of data keys to develop a respective said coded signal; keyboard address means including keyboard address counter means holding a number representative of a said location in said memory means;
pulse generator means responsive to actuation of any one of said data keys to apply a pulse to said address counter means to change the number therein; and
means applying said coded signal and said address number to said memory means whereby to enter said signal in said location.
21. The system claimed in claim 20 and further including coded signal storage means receiving said coded signals developed by actuation of said data keys and signal transfer means operable to transfer said stored signals sequentially to said memory means.
22. The system claimed in claim 20 and further including a repeat pulse generator developing periodically repeated pulses and a repeat key operable to apply said repeated pulses to said keyboard encoder means to produce repeated generation of a said coded signal selected by actuation of a said data key and to said keyboard address means to produce repeated change of said address number.
23. The system claimed in claim 20 wherein said keyboard address counter means includes first and second counters, a tabulator key, number storage means, transfer means operable in response to actuation of said tabulator key to transfer the number in a said counter into said number storage means, a return key and loading circuit means responsive, to the actuation of said return key to set said counter to the number stored in said number storage means.
24. The system claimed in claim 23 and including a line return key, means coupling said line return key to said transfer means, a pulse generator, means initiating said pulse generator in response to actuation of said line return key and means applying pulses generated by said pulse generator to the other of said keyboard address counters, whereby actuation of said line return key returns one said counter to a predetermined state of count and changes by one the count in the other said counter.
25. The system claimed in claim 20 and further including first pulse generator means operable by a first marker key to apply a signal to said keyboard address counter means to change a first component of said address number in a first sense, second pulse gnerator means operable by a second marker key to apply a signal to said keyboard counter means to change said first component of said address number in the sense opposite to said first sense, third pulse generator means operable by a third marker key to change a second component of said address number in a first sense and fourth pulse generator means operable by a fourth marker key to change said second component in the sense opposite to said first sense.
26. The system claimed in claim 25 and further including a repeat pulse generator developing periodically repeated pulses and a repeat key operable when a said data key is actuated to apply said repeated pulses to said keyboard encoder means to produce repeated generation of the said coded signal selected by actuation of said data key and to said keyboard address means to produce repeat change of said address num' her, and said repeat key being operable when a said marker key is actuated to apply said repeated pulses to said keyboard address counter means to produce repeated change of the selected address number component in the selected sense.
27. The system claimed in claim 25 wherein said access means includes display address counter means holding a display address number, said system further including comparator means responsive to said display address number and to said keyboard address number to develop a marker signal when said numbers are iden tical and marker display means applying said marker signal to produce an individual component of said display.
28. The system claimed in claim 27 and further including shifting register means operable alternately to receive signals and to supply signals to control said display, said shifting register means including a plurality of channels receiving signals from said memory means and a further channel, said marker display means operating to apply said marker signal to said further shifting register channel.