US3445838A

US3445838A - Stroboscopic display device with buffer input and separate coded sync drum

Info

Publication number: US3445838A
Application number: US481701A
Authority: US
Inventors: Norman Joseph Appleton
Original assignee: Raytheon Co
Current assignee: Raytheon Co
Priority date: 1965-08-23
Filing date: 1965-08-23
Publication date: 1969-05-20
Anticipated expiration: 1986-05-20

Description

May 20, 1969 N. J. APPLETON 3,445,838

STROBOSCOPIC DISPLAY DEVICE WITH BUFFER INPUT AND SEPARATE CODED SYNC DRUM Filed Aug. 2s. 1965 sheet /NvEn/rof? NoRMA/v J. APPLEro/v Bf JKM ATTORNEY May 20, 1969 N. J. APPLETON 3,445,838 sTRoBoscoPIc DISPLAY DEVICE wITH BUFFER INPUT AND SEPARATE coDED SYNC DRUM Filed Aug. 25. 1965 Sheet 2 Of 4 CUSTOMER |NPUT DATA 40 B432| @W i 1| :l n T:

4 YDLS W54 i@ /Cl (j 5g lr ""/0 l A l o l n 3 I l T- Lu u', 5 I A 9 .A l 7 g l (3) l 600 I 4 I i l g 6 8 /5/ l |/56 704 I Il.. O I V g *"7 l l @PATA A C l FUP LD l w[2 l l`t, FLoPg 1 r *I x l :TAPP-S3 f lf' l I 3 l T., FLIP Y 54"\. 34 "gun"- l I FLOPg 52 SH.56N -f-m' i I I ll 9 I l g 2 i l gm 'D \57 4 l Si -1 9 e I s 'g2 Si nl. 8 Lu J E l V E lip- O I i J I 22 g 35 T0 1 5 FLASH C@ Lz-:a ,C .TUiBE i rl 1'. i f A g i F/G. 5 A 2 l-l /NvEA/rol? 4 NORMA/v J, APP/.70111 READ By "02"H:5ADS 9%* A TTU/PNEY SIGNAL AMPLITUDE May 20, 1969 N. .1. APPLETON 3,445,838

lSTROBOSCOPIC DISPLAY DEVICE WITH BUFFER INPUT AND SEPARATE CODED SYNC DRUM Filed Aug. 23, 1965 sheet 5' of 4 RING GEN. LINE 22 ,L

,E F RING GEN. L LINE 2I LI COLUMN 2 MEMORY DRIFT sPACE COLUMN 2 sPACE f A wr M w -JE MAG.IIEAD4 BI A l Y MAG. HEAD4 B B2 II H H H VL 'C MAG.IIEAD4 B4 MAG HEAD4 D Y FLIP-FLOR D 7 f x FLIP-ELDR C iw PLIP-FLDP D w /V FL'IP-FLoP A L READ IEAD /M REA@ HEAD B3 /N READ HEAD B2 READ HEAD BI n /O CUSTOMER /J INPUT DIT 4 I I IUPSUTTQMIETRB CUsT ER /H INPUT BIT 2 W CUSTOMER C INPUT BIT1 n Ro R+Ieo R'I DECRE Es RoTATIoN /fvI/.E/vrof? F/G. 4 NORMA/v APPLEro/v A 7' TURA/EY N. J. APPLETON 3,445,838

Y DEVICE WITH BUFFER )INPUT AND SEPARATE CODED SYNC DRUM Sheet 4 of 4 /m/E/v fof? Afro/wer I l Il IIIII| .I|||I |l.|| lllll w 2 .mw m .0. Q im J d 5/ |234 5678 |2345678 |2345678 S m S 2 S 4 DN mx o Uw 4 m Uw 5./ m Em M El M El M VT VT VT AA AA Mm LT LT SS VSS ,I ISS L I l l I I l Illl||| |ll||.\|| Ill Y Y Af Y .Y Y Y 4 00 5 STROBOSCOPIC DISPLA sTRoBoscOPlc READ-OUT DEVICE 0F me. 1

May 10, 1969 Filed Aug. 25, 196e NORMAN J. APPLE 7' 0N United States Patent O U.S. Cl. 340-324 8 Claims ABSTRACT F THE DISCLOSURE A display device for displaying a row of characters corresponding to characters encoded on an input signal wherein a rotatable cylinder having a plurality of staggered columns of character shaped openings is provided. A second cylinder having a plurality of character signalling means and rotating in synehronism with the other cylinder is provided, each of the signalling means providing a uniquely coded signal associated with each different character shaped opening. A storage medium is located on the cylinder having the character shaped openings in order to provide temporary storage of the input signal. Finally, sensing, lighting and logic means are included in order to effect the display of the selected character shaped openings.

This invention relates to display means for visually -displaying a plurality of characters in accordance with discrete character manifesting signals, and more particularly to the display or recording of intelligence indicia in response to a suitable sending device.

It is often desirable to provide an instantaneous visual indication or display of the intelligence values or characters at the output of, for example, computer, telemetry, telegraphy or telephony equipment in a form that a human operator can read and understand. Various systems have been proposed and are in current use for providing such displays. These displays may be categorized in general as electromechanical, electroluminescent, or coldcathode glow discharge types. The present invention is related to the electromechanical type and more particularly to the electromechanical stroboscopic type as represented by my U.S. patent, Alpha-Numerical Display Means, No. 3,020,531, issued Feb. 6, 1962; and application No. 416,043, led Dec. 4, 1964, entitled Display Device.

The stroboscopic type display has an inherent advantage over other display devices in that a single light source, such as a flash tube may be time shared by a plurality of characters or indicia. Due to the persistence of vision, such plurality of indicia will appear to be displayed simultaneously and continuously although illuminated successively and intermittently.

While the stroboscopic display means of my aforementioned Patent No. 3,020,531 and my pending application No. 416,043 now Patent No. 3,400,387 is useful for many applications, various disadvantages arise in certain applications due to the complex logic and phasing requirements imposed on the system.

In particular, in both of the foregoing devices the customer input equipment must be maintained static during each scanning revolution of the indicator device. More specifically, the apparatus of my previous patent application No. 416,043 in the main comprises: a rotatable character cylinder having a plurality of staggered colums of character shaped openings arranged about said cylinder; a plurality of character signaling means rotatable in synchronism with said cylinder; each signaling means providing a signal which is uniquely associated with each different character shaped opening; sensing 3,445,838 Patented May 20, 1969 means responsive to said signaling means for providing successive signals corresponding to the coded signal from each signaling means as they rotate past said sensing means; light means for illuminating selected openings in response to an energizing signal; and logic means for comparing the successive signals from said sensing means with the input signal and providing an energizing signal to said light means where a predetermined correspondence occurs therebetween.

inasmuch as it is necessary to compare each successive signal from the sensing means with the gated input signal for each column to energize the light at the appropriate interval, it follows that the input signal for each column from, for example, a computer must be present throughout the whole scanning cycle.

In the apparatus of the present invention the foregoing limitations are avoided by temporarily recording the input signal on a recording medium rotatably synchronized with the character cylinder and the character signaling means. Once the input signal is recorded on the recording medium the input signaling device is free to proceed with other tasks until new information is desired to be displayed. The input signal may be recorded magnetically or electrostatically on a drum, tape, disc or the like. Once recorded, the input signal is Read (converted into an electrical signal by a transducer) and transferred into a static memory device such as an N-bit hip-flop circuit.

The output states of the N-bit flip-flops represent the.

original input signal and such states are compared with successive signals from the sensing means to provide an energizing signal for the light means.

The characters displayed may be any form of intelligence, for example, letters of the alphabet, numbers, symbols, or other such indicia. The light means is preferably of the stroboseopic type and may, for example, be a flash tube with fast recovery time. The character signaling means preferably comprise patterns of `magnetic and nonmagnetic material whose presence or absence can be sensed by a magnetic transducer device, thereby providing a coded signal uniquely representative of the character associated therewith. However, the device is not to be limited to such signaling means inasmuch as it will become apparent that photoelectric or other such means may be readily substituted therefor.

For greater flexibility the character cylinder and recording medium are made integral with one another but separate from the signaling means cylinder. In this manner, various character drums may be provided with the basic display device which drums may be conveniently interchanged to suit the immediate requirements of the customer.

In addition to the foregoing, the maintainability of the apparatus of the present invention is greatly enhanced by locating the light means external to the character drum and through a series yof mirrors projecting the light Ithrough the character openings onto a screen. The light is one lof the chief sources of failure because of the high repetition rate required in stroboscopic operation. Accordingly, ease in replacement thereof, by locating the light external of the drum, greatly decreases downtime upon catastrophic failure of the light source.

The apparatus of the present invention may also be readily adapted for remote readout systems of slave stations slaved to the master readout device. In this context considerablev cost savings are realized at the slave stations since, as will become apparent, only a synchronized motor, a character drum and `stroboscopic light source will be required at the slave station.

The foregoing and other yobjects and features yof the invention may be more readily understood by reference to the following description of an exemplary embodiment of the invention when read with reference to the drawing in which:

FIG. 1 is a planned view of a preferred embodiment of the invention;

FIG. 2 is a front view of the intelligence bearing cyl- Inder -of the invention showing the recording track along the periphery thereof;

FIG. 3 is a schematic diagram of the apparatus of FIG. l in block diagram form showing the electronic logic circuitry associated with the mechanical components of FIG. 1;

FIG. 4 is a graph plotting signal Voltage amplitude versus degrees rotation of the cylinders of FIG. l and showing the idealized waveforms at certain points in the circuit diagram of FIG. 1; and l FIG. 5 is a block diagram of a stroboscopic remote readout system of the invention wherein slaved readout stations are synchronized to the master readout stati-on of FIGS. 1 and 3.

It should be noted that corresponding parts are correspondingly numbered in each of the figures.

Referring now to FIG. 1 there is shown a rotating cylinder 2 consisting of a drum 19 of non-magnetic material such as aluminum, upon which, is wrapped a sheet comprising thin optically transparent nonferrous -rna-terial 27, such as clear Mylar, lamin-ated to a base `of ferrous material 26, such las iron sheet stock. An aluminum end plate 31 is affixed to -one end of cylinder 2. A shaft 14 is rotatably affixed to plate 31 and extends inwardly therefrom. Drive motor 16 is coupled to shaft 14, and shaft 414 is xedly secured -to cylinder 2 by means of an internal spl-ine on cylinder 2, not shown, whereby cylinder 2 is made to rotate -in synchronism with drive motor 16. 'Magnetic bar 18 is also affixed to shaft 14 from which it may be seen that the magnetic bar and cylinder are rotatably mounted and may be rotated in synchronism with drive motor 16. Character drum 1'5 is structurally similar to cylinder 2 and consists of an inner opaque drum 35 having spline 351 raxially affixed to an inner surface through which shaft 14 extends and may be secured thereto. Drum 35 may be molded of non-magnetic material such as plastic or the like. Transparent character -openings are arranged in character areas, preferably in staggered columns, so that a line drawn perpendicular to the columns would pass through but one character. These openings may consist of character shapes formed by removing or eliminating the opacity of the plastic drum by -a photo engraving process or the like in a well known manner.

Light source 1, reflector 5, condensing lens 6r, projecting lens 7 and 45 mirrors 450 and 451 form an optical system in alignment with magnetic pickup device 4 and cylinders 2 and 15, such that when a row of coded patterns on cylinder 2 is being sensed at magnetic pickup head 4 by the plurality of sensors therein, the corresponding character shaped opening on cylinder 1'5 appears disposed in the optical system vertically centered at the projection of the arc from lamp 1 on the internal surface of cyl- `inder 15. The projection of the arc from lamp 1 on the surface of cylinder 15 is sufficiently wide so as to encompass the width of all the character column openings on cylinder 15. The height of the projection of the arc from lamp 1 onto cylinder 1'5 is sufficiently high so as to cover one row of character openings. However, since the character columns are staggered, only one character at a time is displayed on screen 29. By locating light source 1 outside of the cylinders 2 and 15 ease of maintenance is greatly enhanced as aforesaid.

A plurality of signaling means, shown generally at 46, are encoded on the cylinder 2, each such signal means positionally associated with a corresponding column character and each signaling means providing a signal uniquely associated with each different shaped character opening. In the preferred embodiment of FIG. l the signaling means consists yof patterns of bar shaped areas wherein the ferrous material has been etched and removed. The characters are the numerals 0-9 and the patterns form the binary coded complement of each respective adjacent numeral.

Magnetic head device 4 having a plurality of magnetic heads is spaced apart from the cylinder 2 adjacent the patterns and reads" or senses the information stored on the cylinder as the cylinder is rotated past the magnetic head device 4 at a speed, for example, in excess of 1800 r.p.m. The magnetic head may be a conventional transducer which converts the stored patterns into electromagnetic on-o signals. Individual magnetic heads sensitive to change in reluctance are contained in device 4, each head adjacent a respective column of signaling means.

Description of memory In the apparatus of the invention, a memory area or recording medium is provided. This area may be located either on cylinder 2 or cylinder 15 or on a separate medium rotatably synchronized with the latter two cylinders. In the embodiment of FIG. 1, the storage or memory area is provided adjacent the character columns on a track of magnetic film deposited on the cylinder. Alternatively,v the memory area may be located intermediate the end of one column of character openings and the beginning of the next column of character openings on cylinder 15.

The recording medium may consist of any of the wellknown magnetic lms, such oxide coatings formed from a dispersion of ferrous oxide in an organic binder or cobalt-nickel platings. The recording media is shown at 151 on cylinder 15 and may be molded, dipped or sprayed onto the cylinder in the desired location.

Adjacent cylinder 15 and lnounted on bracket 153 is Write head 154. Write head 154 consists of four magnetic heads arranged in parallel. Each head consists, basically, of a magnetic core having a gap and wound with a wire coil. Each Write magnetic head provides a confined and intense magnetic field at the storage surface.

A Read head, not shown in FIG. 1, is located, for example, from the Write head 154 and likewise consists of four transducers or magnetic heads arranged in parallel, each magnetic head providing a magnetic shunt for surface flux arising from the magnetized state of the recording surface. Again, the magnetic heads in the Read head consist of a magnetic core having a gap, said core being wound with a coil. After the Read head, and intermediate the Read head and Write head, an Erase head is located adjacent the drum which erases or removes the data on the memory medium by demagnetization. The medium is thereby prepared for a new input signal or a re-recording of the prior input signal from Write head 154. For details of Various type recording heads and storage media, reference is made to the text Digital Magnetic Recording by Albert S. Hoaglund, published by John Wylie & Sons, Incorporated, copyrighted 1963.

The mechanical and electronic cooperation between the magnetic storage media 151, the Write, Read and Erase heads and the character openings and coded pattern on cylinder 2 may now be best described in connection with the schematic drawing of FIG. 3, taken in connection with the assembly drawing of FIGS. 1 and 2.

In FIG. 3 it can be seen that there are N columns of character openings on cylinder 15 designated C1, C2, C3, etc. In the embodiment shown the characters consist of the digits 0` through 9. A drift space 37 is .provided at the end of each column to enable the flash tube 1 to recover before the start of the next column. Adjacent each number on cylinder 15 are located signaling means on cylinder 2 which provide signals corresponding to the `binary coded complement of the corresponding adjacent number. For example, the digit 1 on cylinder 15, column 1, is represented in binary form by the bit l followed by the bits 000 on row 1 in cylinder 2.

The bit 1 signaling means is a pattern consisting of a bar shaped area of nonferrous material such as Mylar. The pattern is formed by etching away the ferrous shim stock from cylinder 2. For the bit 0, no ferrous material is removed, hence no reluctance change is sensed when this portion of the pattern passes the pickup heads in device 4.

The complement of the digit 1 is the bit 0 followed by bits 111. There is thus formed four columns of signaling means, each row uniquely representing an adjacent character opening.

Magnetic head device 4 having a plurality of magnetic heads B1, B2, B4 and B3, each head sensing change in reluctance caused by the presence or absence of adjacent ferrous material as the drum 2 rotates past the head, provides individual output signals to exclusive OR

gates

10, 11, 12 and 13. The voltage output after one stage of amplification and shaping from each of the four magnetic heads of device 4 is shown as respective voltage curves A, B, C and D of FIG. 4 wherein curve A represents the output of the B1 magnetic head versus drum rotation as each column passes the head. It becomes apparent that substantially the same output Will appear when each column of signaling means passes the head. The polarity of the original pulses from the magnetic heads are inverted by the one stage of amplification not shown. In any event, the relative polarity of the input pulses to the Exclusive OR gate circuits is primarily predicated on whether the transistors used in the Exclusive OR gate circuits are P-N-P or N-P-N. A second stage of amplication, not shown, inverts the pulses from the head to their original polarity. Curve B represents the output of the B2 head, curve C the B4 head and curve D the B3 head. The output of magnetic heads B1 through 4 are separately coupled through cable 40 to separate Exclusive OR gates. The B1 output is coupled to Exclusive OR gate 10, the B2 head output is coupled to Exclusive OR gate 12, B3 to Exclusive OR gate 11 and B4 to Exclusive OR gate 13.

For illustrative purposes, let us assume that the customer input signal is the digit one to be displayed in column two. In bit parallel binary form this would appear as the signal shown on lines G, H, I and I of FIG. 4 at time R0. The voltage pulse on line G represents the bit one and the absence of a pulse on lines H, I and I represents the bit zerof By means of the ring generator apparatus 36, subsequently described, the customer input signal is synchronized with the drum so that customer information, which is only present momentarily, is passed or gated into Write head 154 when the magnetic medium 151 succeeding the column 1 character openings is one-hundred and eighty degrees from being adjacent Write head 154, The input signals G, H, I and J are preferably written on the memory area in the drift space 37 between columns. However, it is not necessary that the Writing occur at the drift spaces.

One-hundred eighty degrees later, at time R04-180, when the drift space succeeding column 1 is adjacent magnetic Read heads 702, the stored input signal on the memory area is read out, producing the four slgnals shown on lines O, N, M and L. The four separate Read signals from head 702 are individually coupled to the four ip-ops circuits of static storage device 704. The output state of each flip-flop is changed by recelpt of an input signal. These changed output states are malntalned until receipt of a clearing signal from ring generator 36 indicating that the next column is to be read.

Accordingly, the output of flip-flops 704A through D may he represented by the voltage waveforms at lines V-Y of FIG. 4 for the aforesaid input conditions. The output signal from respective flip-flops 704A through D is coupled to a respective one of four Exclusive -OR gate circuits -13. As previously mentioned, the other input to the Exclusive `OR circuits is the magnetic head 4 column signals shown on lines A-D of FIG. 4. Thus for example, under the aforesaid assumed conditions the input to Exclusive OR gate 10 from lead 50 is the signal V of FIG. 4. The other input lead to Exclusive OR gate 10 is signal A of FIG. 4, which represents the output of magnetic head B1 through one passage of column 1 past magnetic head B1.

An Exclusive `OR gate circuit provides an output signal on line S5 when one, but not both, positive pulse input signals is present. Similarly, under the assumed conditions, the output of magnetic head B2 represented by curve B `of FIG. 4 is compared with the voltage waveform W of FIG. 4, representing bit 2 of the customer input information, in Exclusive OR gate 12, and an output is obtained from line 54, which is substantially identical to the original waveform of curve B. The outputs of each of the four Exclusive OR gates are separately coupled to AND gate 34. AND gate 34 produces an output signal only when four voltage signals are present at its input simultaneously. By comparing curves A, IB, C and D (the magnetic head inputs) with curves V, W, X and Y (the customer input information statically stored in flip-flops 704A-D), respectively, in respective Exclusive OR gates, it becomes apparent that during the time period represented by the scanning of one column on the cylinder there is only one instant wherein an output will be received from all four exclusive OR gates and that instant is when the pulses at time R1 of FIG. 4 occur. It Will also be noted that at this instant of time the complementary code for the numeral 1 is passing magnetic head 4. As previously mentioned, the magnetic heads, the coded information, and the optical system are aligned so that at the instant the magnetic head picks up the coded information, the corresponding transparent character opening is in the center of the optical viewing area. Accordingly, the output of the AND gate 34, after suitable filtering and amplification in devices `69 and 70, is used to -flash the flash tube in the well known manner. In like manner, subsequent customer input information is memorized by lthe apparatus of the invention and uniquely presented on the screen. Subsequent columns are Read onto the drift space located 180 before the column displayed.

T ming apparatus In order to insure that the character column of the input signal and the character column of the displayed character are in synchronism during the logic comparison process aforementioned, a synchronizing signal is developed in accordance with the invention from ring generator device 36. The ring generator device indicated generally by the numeral 36 in FIGS. 1 and 3 generates a plurality of gating signals of pulse width corresponding to the circumferential width of each column scan duration. Ring generator 36 includes a shaft 14 axially coupled to cylinders 2 and 15 to which is aixed va magnetic bar 18 having an outer arcuate surface 41 forming an arc of length substantially equal to the circumferential length of each of the columns C1 through CN of character openings on cylinder 15. A non-rotating iron core or ring 3 having a plurality of coils 20L-25 encircling it at spaced intervals corresponding to the start of the `drift space preceding each staggered column of characters is ixedly secured to support member 17. The core 3 provides a high density path for lines of flux, shown in dotted lines, to traverse from one pole of magnet 18 to the other. Magnetic bar 118 rotates within the core.

The coils are responsive to the rotational position of' the bar, inasmuch as passing of the bar causes an induced in the coil due to the crossing of the flux lines. Each coil provides a voltage signal, the lower plateau of which is utilized as a gating signal.

The plateau signal from coil 21 is represented by the voltage waveform of curve E of FIG. 4. The plateau for the output of coil 22 appears on curve F of FIG. 4, from which it may be seen that each of the coils provide gating signals of pulse width proportional to the length of each column of openings (including any length associated with drift space), said signals occurring in time coincidence with the passage of successive columns of openings past light source 1. Depending upon the type of llip-flops used in static device 704, the gating signal from the coils may or may not have to be differentiated to provide a clearing pulse. For example, typical flip-flop circuits, such as those shown in the text Digital Modules, published by the Digital -Equipment Corp., copyright 1962, on page 15, require only a momentary pulse at one of the input leads. In this case, it would be preferable to differentiate the pulse from the coils and use the trailing edge of the coil pulse which corresponds in time to the column preceding the column to be Read, to clear the four flip-flops.

Various other systems for synchronizing the flip-flops With the position of the column openings may be devised. For example, the ring generator 36 may have an iron bar with a much shorter arcuate surface corresponding, instead of to a complete column, just the drift space of each column. In this instance, the pulse from the coil could be used directly to clear the flip-flops.

In like manner, the coil signals from ring generator 36 are used to transfer the customer input signal from the customer output device which may, for example, cornprise a shift register or the like, to the Write head. The trailing edge of the coil signal which is one-hundred and eighty degrees from the column to be read is used to trigger the transfer of the input binary digits from the customer.

It should be emphasized that if the customer input information is in bit serial form rather than in bit parallel form, as shown, it may be written on track 151, as is (in serial form), with one magnetic head, thus greatly simplifying the transducer requirements of the read-out apparatus. In this case, Read head 702 would likewise consist of a single magnetic head which would read the bit serial information into four flip-flops connected as a shift register. Gating would be accomplished in a similar manner, the only additional requirement being that it might be necessary to utilize a coded timing pulse on the recording media which would produce in a separate magnetic head a very accurate synchronization pulse for feedback to the customer input apparatus.

In general, the logic circuitry of the invention, and particularly that of FIG. 3 comprising Exclusive OR gates and flip-flops and AND gates, may consist of any of the well-known transistor-resistor or transistor-diode combinations for performing such functions as will be apparent to those skilled in the art. For example, such circuits are described in detail in the texts Transistor Circuit Design prepared by the staff of Texas Instruments, Incorporated, McGraw-Hill Book Company, Inc., 1963, chapter 29, or Digital Computer Principles by the staff of Burroughs Corporation, McGraw-Hill Book Company, Inc., 1962.

Remote readout system As previously noted, the apparatus of the present invention may be readily adapted for a novel and simplified remote readout system comprising slave stations which are slaved to a master data display device such as the readout device of FIG. 1. Such a system is shown in the apparatus of FIG. 5. Referring now to FIG. 5 there is shown a stroboscopic readout device such as that of FIG. l, designated by the numeral 500. Remote readout devices at

stations

502, 504 and 506 are provided which are slaved to the data being displayed on device 500'.

These remote readout stations require only two signals from the master station 500 and are much simpler in physical content than the master station 500. The two input signals to the slave stations are (1) a synchronizing signal which synchronizes the

motors

510, 512 and 514 of the respective slave stations in frequency and phase with the motor driving the cylinders in the master readout device 500 and (2) the output pulse from AND gate 34 suitably filtered and amplified. The output pulse is used to

flash tubes

520, 522 and 524 at the remote readout station. The light sources are projected onto respective character drums 540, 542 and 544, similar to the character drum 15 in FIG. 1, by means of mirror and

lens systems

530, 532 and 534, respectively. Since the character drums 540, 542 and 544 are rotated in synchronism with the corresponding character drum and master device 500, the appropriate character opening is illuminated and projected on the remote readout screens 550, 552 and 554, respectively. It thus becomes apparent that the remote readout device of the present invention is greatly simplified inasmuch as the magnetic memory, the encoded drum and the logic circuitry may be dispensed with in the slave stations. Furthermore, only a single `communication line is required to transmit the pulse signal to the light sources at each slave station. The signal synchronizing the motors may require a three Wire Selsyn or servo system. However, if all the motors are operated from a well-regulated frequency source, it may be possible to dispense with the servo mechanism system between the

motors

510, 512 and 514 and the master station, provided suitable phasing mechanisms are available for appropriately slaving the remote readout slave stations to the phase of the master motor.

This completes the description of the preferred embodiments of the invention. However, many modifications thereof will become apparent to those skilled in the art.

What is claimed is:

1. Indicator means for displaying a row of characters corresponding t0 characters encoded on an input signal comprising:

a rotatable cylinder having a plurality of staggered columns of character shaped openings;

a plurality of character signalling means rotatable in synchronism with said cylinder, each signalling means providing a unique coded signal associated with each different character shaped opening;

storage means located on said cylinder for storing said input signal;

sensing means responsive to said signalling means for providing successive signals corresponding to the character 4code from each signalling means as each row is rotated past said sensing means;

light means for illuminating selected openings in response to an energizing signal; and

logic means, including means for recording said input signal on said storage means, for comparing the successive signals from said sensing means with the input signal and providing an energizing signal to said light means when a predetermined correspondence occurs therebetween.

2. Indicator means for displaying a row of characters corresponding to characters encoded on an input signal comprising:

a first rotatable opaque cylinder having a plurality of staggered columns of transparent openings arranged circumferentially thereon, each opening having a characteristic shape corresponding to a character to be indicated;

a second rotatable cylinder adjacent to and rotatable in synchronism with said first cylinder, said second cylinder having a plurality of rows of character signalling means encoded thereon, each row providing a signal uniquely associated with each different shaped opening;

memory means located on one of said cylinders for recording said input signal so that the input signal for each column need not be present throughout the whole scanning cycle;

sensing means responsive to said signalling means for providing successive signals corresponding to the character code from each row of signalling means as each row is rotated past said sensing means;

light means for illuminating said openings in response to an energizing signal;

and logic means for comparing the successive signals from said sensing means with the recorded input signal and providing an energizing signal to said light means when a predetermined correspondence occurs therebetween.

3. Indicator means for displaying a row of characters corresponding to characters encoded on an input signal comprising:

a first rotatable cylinder having a plurality of staggered columns of character shaped openings;

a second rotatable cylinder adjacent to and rotatable in synchronism with said first cylinder having signalling means for providing a coded signal associated with each different character shaped opening;

sensing means responsive to said signalling means for providing successive signals corresponding to the character code from each signalling means as each row is rotated past said sensing means;

memory means located on said first cylinder for temporarily storing said input signal;

recording means for recording said input signal on said memory means;

logic means for comparing successive signals from said sensing means with the recorded input signal and providing an energizing signal when a predetermined correspondence occurs therebetween;

light means for providing a ray of light in response to said energizing signal;

and projecting means for projecting said ray of light on the interior surface of said first cylinder.

4. The apparatus of claim 3 wherein the projecting means includes a pair of mirrors disposed at a 9.0 degree angle from one another and 45 degrees from said light source.

5. The apparatus of claim 4 wherein the recording means includes means for magnetically recording said input signal.

6. An information display device for displaying a row of characters corresponding to characters encoded on an input signal, and said device comprising:

a first moveable member bearing intelligence units in the form of staggered columns of character shaped openings;

memory means located on said first member and including a magnetic record medium and a magnetic head for magnetizing said medium in at least one track extending longitudinally of said medium, for storing information to be displayed;

transducer means for reproducing said stored information;

signalling means permanently recorded on a second member moving in synchronization with said first moveable member for providing a plurality of pulse trains, the time relationship of pulses in each train with pulses in each other train bearing a predetermined relationship to different intelligence units;

and logic means for comparing said pulse trains with said reproduced stored information to visually arrest an appropriate intelligence unit.

7. Indicator means for displaying a row of characters corresponding to characters encoded on an input signal comprising:

memory means located on said first cylinder for recording said input signal so that the input signal for each column need not be present throughout the whole scanning cycle, said memory means including a magnetic record medium located around the periphery of said first cylinderand a magnetic head for magnetizing said medium in at least one track extending longitudinally of said medium, for storing information relating to the character shaped opening to be displayed, said stored information relating to each individual character being located on said medium 180 from the column to be read;

means for synchronizing the input signal with said first cylinder so that the input signal, only momentarily present, is passed into said magnetic head when said magnetic medium succeeding the column to be read is 180 from being adjacent said magnetic head;

light means for illuminating said openings in response to an energizing signal;

logic means for comparing the successive signals from said sensing means with the recorded input signal and providing an energizing signal to said light means when a predetermined correspondence occurs therebetween; and

projecting means including a pair of mirrors disposed at a angle from one another and 45 from said light means for projecting said light on the interior surface of said first cylinder.

8. Indicator means as set forth in claim 7 wherein said synchronizing means includes a ring generator coupled to said first and second cylinders for generating a plurality of gating signals of pulse width corresponding to the circumferential width of each column scan duration in order to insure that the character column corresponding to the input signal and the character column corresponding to the displayed character are in synchronism during the comparison by said logic means.

References Cited UNITED STATES PATENTS 2,950,662 8/ 1960 Higonnet et al. 178-15 3,007,380 11/ 1961 Ketz et al 95-4.5 3,165,045 1/ 1965 Troll 178-15 3,222,666 12/ 1965 Hallden S40- 324 3,331,299 7/ 1967 Morgan 340-324 JOHN W. CALDWELL, Primary Examiner.