US2381902A - Television transmitting system - Google Patents

Description

Aug. 14, 1945.

Fig. 1

A. N. GOLDSMITH TELEVISION TRANSMITTING SYSTEM Filed Dec. 20, 1944 2 Sheets-Sheet l IMAGE SIGNAL AMPL/F/ER VERTICAL DEFLECT/ON GENERA TOR (60-) HORIZO/VML DEFLfCT/ON GENERATOR AUTO-TRAN5FORMER T0 LIA/E sm/c GE/VEQATOR /MAGE SIGNAL AMPLIFIER S if OUTPUT TO TRANSM/ T7'Ek INVENTOR.

ALFRED N GOLDSM/TH ATTOENEK 1945- A. N. GOLDSMITH TELEVISIO N TRANSMITTING SYSTEM Filed Dec. 20, 1944 2 Sheets-Sheet 2 Fig. 2.

119/ Ill srua/o mam-s ourar TO TRANSM/TTER m MM .y mm W VL O m Awm m w o 4 A m ir. h

a o 5 a a H n n L H 5 40 cfim Man 2* e M a 0p 0 m H0 Patented Aug. 14, 1945 UNITED STATES PATENT 13 Claims.

This invention relates to an improvement in television transmitters and advances and carries forward still further the improvements shown by my U. S. application for Letters Patent, Serial No. 456,133, filed August 26, 1942. More particularly, the present invention relates to a system wherein it is possible to present television images in slow motion with forward and/or reverse sequence, in normal motion with forward and/or reverse sequence, or in any desired combination of these motions or sequences.

The use of slow motion in television is highly desirable but has heretofore been impossible, since no practical arrangement has been devised, prior to my above mentioned patent application, whereby it is possible to present television images in slow motion, particularly where the subject matter is obtained from direct pick-up.

Altering the rate of motion, with or without a change in sequence, in the moving picture field is relatively simple, since it entails merely the operation of a camera at a different and desired rate of speed to expose successive frames of a film. After processing and printing the film is then run through a projector at normal projection rates with the result that the subject matter photographed, together with the apparent motion and sequence, is shown at the desired rate and in the desired sequence.

Altered motion and sequence in television could conveniently be exercised if a film intermediate may be used, since the film technique of the moving picture field could be employed. However, altering the rate and/or sequence of motion in television, from the standpoint of direct pick-up, is not simple and necessarily'entails the use of an appropriate assembly of apparatus. Some relatively long-term picture storage means must be television images are derived from direct pick-up. Such a television system is highly desirable at races or other competitive or sporting events to observe in detail an action which transpires in a relatively short length of time or for various other purposes familiar to those skilled in the art.

The present invention is concerned primarily with the production of slow motion television images in reverse sequence together with the circuit arrangements necessary for producing such a change in the apparent rate of motion and for producing such a sequence change. Another formof the present invention relates to a circuit arrangement whereby it is possible to produce, in slow motion, a series, of events that are pres'ented first in a forward or normal sequence and immediately afterwards in a reverse sequence.

provided, since the subject matter per se cannot be slowed down; and where the subject matter I being transmitted is derived from direct pick-up,

special means are provided whereby electrical replicas of a series of successive television frames may be stored or retained for predetermined lengthsof time inorder that they may be immediately subsequently, or shortly subsequently used to produce images on the screens of the various television receiving apparatuses.

My above referred to patent application discloses slow motion (in normal sequence) without the use of an intermediate film, and provides means whereby it becomes possible, at any particular desired instant, to portray in slow forward motion a certain occurrence even though the subject matter is being immediately televised, and the The present invention further contemplates the provision of a circuit arrangement whereby it is possible to present television images at their normal rate but in reversed sequence as well as further considerations of combinations of these various circuit arrangements whereby other desired rate and sequence changes may be made available.

It is, therefore, one purpose of the present invention to provide a. slow motion television transmitting system for transmitting, in reverse sequence, television images for a predetermined period of time, the slow motion interval being preceded or followed as may be desired by either normal motion or slow motion images.

Another purpose of the present invention resides in the provision of means for transmittin television images in reverse sequence slow motion wherein the movement following the reverse slow motion interval is immediately portrayed in normal motion with an omission of only part of the normal motion which transpired during the time of presentation of the slow motion images.

Still another purpose of the present invention resides in the provision of a slow motion television transmitting system wherein the motion may be portrayed in slow motion first in one sequence, followed immediately by a slow motion 'presentatiorr of the same motion in a reverse sequence.

Still another purpose of the present invention resides in the provision of a plurality of television images storing devices whereby electrical replicas of the motion may be retained for a predetermined length of time for subsequent use in presenting the desired change in motion and sequence of the television images.

A further purpose of the invention is to provide means for appropriately and, if desired, automatically changing the intensity or character of the illumination of the televised scene during the altered motion pick-up period.

Still other purposes and advantages will become more apparent to those skilled in the art from the following detailed description, particularly when considered in connection with the drawings wherein: I

Figure 1 represents, by way oi. example, one embodiment of the present invention for presenting slow motion reverse sequence images, and

Figure 2 represents, by way of example, a circuit arrangement for presenting slow motion first in normal or forward sequence followed immediately by the same motion in reverse sequence.

In order that true slow motion television images may be presented it is necessary to scan the subject matter or an image of the subject matter at an increased scanning rate to thereby produce picture signals representative of a relatively large number of individual and sequential images of the particular subject matter. In normal tele-. vision transmission practice the subject matter to be transmitted, or an image thereof, is scanned at a predetermined rate to thereby produce image or video signals which, after transmission to the receiver, are utilized to produce television images. Accordingly, in the present slow motion television system two separate television pick-up cameras are utilized, one of which is operated at normal image transmission speed, and the other of which is operated at a higher rate of speed, preferably at some multiple of the operation of the normal television pick-up camera.

Referring now to the drawings and particu larly to Figure 1, there is shown a conventional television pick-up camera tube l0 having a mosaic electrode l2, including a light sensitive surface and a signal plate and wherein an electron gun structure I4 is also provided to develop a scanning electron beam. Associated with the pick-up tube is a lens system l6 for projecting optical images of the subject matter to be televised upon the mosaic electrode I2. The electron gun structure [4 when subjected to proper operating potentials develops a cathode ray beam which when deflected in mutually perpendicular directions by means of the deflecting coil i8 is caused to scan the surface of the mosaic electrode I2 to produce image signals which are applied to an image signalamplifler 20. For deflecting the cathode ray beam in both horizontal and vertical directions a vertical deflection generator 22 is provided, as is also a horizontal deflection generator 24. The vertical deflection generator is supplied with timing impulses in order that the deflection frequency may be maintained constant and, in order that the proper ratio of deflection rates maybe maintained, frequency dividers or multipliers are generally interposed between the vertical and horizontal deflection generators.

In order to facilitate in describing the operation of the present invention it will be assumed, by way of example, that the normal operating frequency of the normal speed television pick-up tube I0 is at 60 fields per second and at 15,750 lines per second (that is at the rate of 30 double interlaced 525 line images per second). Accordingly, the voltage variations supplied by the vertical deflection generator 22 will vary in wave form at the rate of 60 cycles per second, whereas the horizontal deflection generator 24 will produce voltage variations having a frequency of 15,750 cycles per second. Energy from both of these deflection generators is then applied to the deflecting coil ii in order deflect the cathode ray beam in mutually perpendicular directions at the desired rates in order that the mosaic electrode may be scanned to produce image signals. The image signals-after amplification are then available at the output conductor 26, provided the movable arm of rotary switch C is in contact with segment 28 as shown in the drawings.

For the purpose of this description it will be assumed that the retardation ratio is 4 to 1, and on this assumption the television pick-up camera that is used for the production of slow motion television images will operate at exactly four times the speed of the normal television pick-up tube. A second television pick-up tube 30 is, therefore, provided which is similar to tube In. The tube also has associated therewith a deflecting coil 32, and the deflecting coil is supplied with energy from an associated vertical deflection generator 34 and horizontal deflection generator 36. The vertical deflection generator is controlled to operate at 240 cycles per second (assuming a 4 to 1 retardation ratio), while the horizontal deflection generator is controlled to operate at 63,000 cycles per second. When energy from these two deflection generators is supplied to the deflecting coil 32 of tube 30 the cathode ray beam will be caused to scan the mosaic electrode at a line frequency of 63,000 lines per second and a field frequency of 240 fields per second. It is convenient to operate the timings of deflection generators 34 and 36 as multiples of those of the respective generators 22 and 24 by the interposition of suitable frequency multipliers therebetween.

Scanning of the mosaic electrode in tube 30 produces image signals which are amplified by the image signal amplifier 38. Inasmuch as the scanning rate in tube 30 is assumed to be four times the scamiing rate in tube l0 then the generated image signals will have a maximum frequency of the order of four times-the maximum frequency of the image signals generated by the pick-up tube ill. The image signal amplifier 38 must, therefore, be of exceptionally wide band width in order that an extreme range of image signals may be amplified thereby with the proper degree of fidelity. The image signals after appropriate amplification are then impressed upon conductor 42.

To provide the desired reverse slow motion effect, switches A, B, C, D, E, F, G, H and J are employed and they are mechanically or otherwise interconnected so that when reverse slow motion television pictures are desired the switches are simultaneously operated to apply image signals to the slow motion storage network and to simultaneously transmit signals representing the same motion. Subsequently, image signals derived from the slow motion storage circuit are made available in reverse sequence at the output terminal 26. The image signals available from the terminal 26, either as derived directly from pickup tube III or indirectly from the slow motion pick-up tube 30, are then subjected to further amplification and have combined therewith line and frame synchronizing signals (of normal frequencies) which are supplied by a line or frame synchronizing generator (not shown). To control the line and frame synchronizing generator energy may be applied thereto from the vertical and horizontal deflection generator; 22 an 24, respectively. After the synchronizing signals have been combined with the image, signals the composite series of signals may then be used to modulate a-radio frequency carrier for radio transmission to television receivers.

In addition to assuming, by way of example,

' that the retardation factor is taken as four, it

will be assumed also that normal action for a time duration of one second wilibe expanded.

into four seconds of reverse slow motion television. In other words, movement which transpires in an interval of one second is presented in reverse slow motion having a duration of four seconds.

For storing the very rapidly produced image signals or images corresponding thereto a plurality of storage tubes are provided three of which are shown at 44, 45 and 46. The specific construction of these storage tubes will not be discussed in detail, since a description'of such a tube is to be found in the publication Television by Zworykin and Morton (John Wiley 8: Sons, Inc., 1940) on pages 326 and 32?. The tubes, however, include a double sided mosaic electrode 48 and two gun structures 50 and 52. The gun structures are arranged to scan opposite sides of the mosaic 48 and when a modulated cathode ray beam is caused to impinge upon one side of the mosaic an electrostatic charge image will be produced thereon which may be removed by the electron gun structure in the opposite end of the tube. Image sig-v I nals are, therefore, applied to the second anode 54 of tube 44, for example, with the result that the individual elements of the mosaic electrode 48 will assume a potential which is dependent upon the instantaneous potential of the second anode. For storing the charge image on the mosaic 48 the cathode ray beam generated by the gun structure 50 is naturally used. When the scanning action is completed a potential variation will exist over the mosaic which is a result of the voltage variation applied to the second anode 54. When the opposite side of the mosaic 48 is scanned by the cathode ray beam produced by the gun structure 52 signals may be derived from the second anode 56 associated with this cathode ray beam. The potential variations which exist on the mosaic electrode 48 are, therefore,

transformed into a signal which may be collected from the second anode 58 when the mosaic is scanned by the cathode ray beam. Naturally, a deflecting means is associated with each gun structure, but such means has been omitted in the drawings for simplicity.

While a specific form of image storage tube has been here shown and described, it is to be understood that there may be substituted therefore, and within the scope of my invention, any equivalent structure wherein an image may be electrically impressed and stored and thereafter scanned and made available again as an image or video signal.

If, as above assumed, a time duration of one second is to be expanded into four seconds of reverse slow motion television, then 120 storage tubes will be required. Each storage tube is capable of retaining a complete television image frame including two field scansion cycles. This is on the basis that a2 to 1 interlace scanning system is employed as is standard television practice. When interlaced scanning is employed two succ ssive television fields are required to complete a television frame and an electrostatic charge image of a complete television frame (instorage tube. The" charges representing cache! the two fields may be removed in succession by the cathode ray beam produced by the gun structure 52 when the mosaic electrode 48 of the storage tube is scanned by an interlaced pattern. When no interlacing is employed then naturally a number of storage tubes must be employed corresponding to the number of fields which are scanned bythe slow motion television camera during the interval at which reverse slow motion images are to be presented.

In order that the individual image signals as produced by the slow motion television pick-up tube 30 may be successively applied to the storage tubes so that the images may be retained for a predetermined length of time and until they are removed in reverse sequence, some switching arrangement must naturally be employed. Likewise, a similar switching arrangement, operating in synchronism with the normal motion pick-up tube, must also be employed for removing the stored signals.

As previously stated, the switching arrangement necessary to produce the desired slow motion efiects includes, for example, rotary switches A, B, C, D, E, F, G, H, and J. All of these rotary switches are mechanically or otherwise connected together in order that they may operate at prescribed relative rates and at, prescribed phase relationships. They are all driven, for example, by means of a single motor 60 which operates at 0.2 revolution per second. The movable arm of switches C, D, E, F, G, H, and J, are all rotated at that same speed. Switches A and B, however, have included in their drive shafts, gear ratios such thatthey will be rotated-at 1.0 revolution per second. All of the switches as shown inFigure 1 are in a position for normal television transmission in which the signals derived from the normal pick-up tube H) are made available at the output conductorZB. Under these conditions, image signals from the normal pick-up tube 10 are transmitted through the image signal amplifier 20 and are applied to conducting segment 28 of switch C. Normally the rotating contact of switch C is in electrical co-operation with this segment. The rotating contact of switch C then supplies image signals to the output conductor 26.

The output conductor 42 that is associated with the image signal amplifier 38 of the slow motion television pick-up tube 30 is connected to the movable contact arm of switch G. In normal conditions, this switch arm rests on an insulating spot adjacent conducting segment 62 so that the circuit from the image signal amplifier is discontinuous. I

When reverse slow motion television images are desired, it is only necessary to start the operation of the motor 60 and it is preferable that this motor have in its starting circuit some arrangementjor maintaining its operation for one complete operation cycle. Rotation of the motor causes a rotation of all of the movable switch arms in the directions indicated. It will be observed that the movable arm of switch C remains in contact with the conductingsegment 28 throughout approximately 72 of rotation of the arm. This represents about As of a complete revolution and since the speed of rotation of the arm is 0.2 revolution per second, the movable arm of switch C is in contact with segment 28 for approximately one second. During this interval, image signals from the normal motion 4 pick-up tube I are applied by way of conductor 20 to the television transmitter. Simultaneous with .the transmission of the television image signals from pick-up tube I0, image signals are produced by the slow motion television pick-up tube 30. These image signals are applied to and are stored on the storage tubes 44, 45 40. Since the slow motion television pick-up tube 30 operates at four times the normal operation rate, 240 television fields or 120 television frames will have been scanned. The produced image signals are then stored on the I20 storage tubes, three of which are indicated at 44, 45 and".

The circuit arrangement for permitting storage of these signals is as follows: Image signals as obtained from the image signal amplifier are directed to the movable arm of switch G by conductor 42. During 72.of rotation of the movable arm of switch G these signals are applied to the movable arm of switch B. By reason of the gearing interposed between switches G and B, the movable arm of switch B will make one complete revolution during the time the movable arm of switch G is rotating through approximately 72 (the length of the conducting segment 62). The movable arm of switch B cooperates sequentially with 120 individual conducting segments which are connected individually to the 120 storage tubes. As shown in the drawings, the first and second segments are connected to storage tubes 44 and 45 while the conducting segment I20 is associated with storage tube 46. Accordingly, the image signals representing the 1 0 slow motion television frames are sequentially stored on the storage tubes in the order 44. 45 4B. Atthe end of this one second interval, the movable arm of switch C is disconnected from the conducting segment 28 so that image signals are no longer supplied to the transmitter from the normal speed television pick-up tube I0. The movable arm of switch 0 then contacts the conducting segment 64 to supply the reverse sequence slow motion image signals to the television transmitter. These reverse sequence slow motion image signals are obtained from the movable arm of switch D, which, immediately following the storage interval of one second, is on contact I20 that co-operates with the second anode 56 of the last storage tube 46. Image signals of the last stored image are then directed to the television transmitter and upon further rotation of the movable switch arms, image signals are derived from the storage tubes in a reverse order with the movable arm of switch D finally co-operating with storage tubes 45 and 44. The removal of the stored images is at normal television transmission rate and accordingly reouires a four second time interval to remove all of the changes that were stored during the one second storage interval (on the basis of 4 to l retardation factor). The entire cycle including the storage and the subsequent removal of the stored images in reverse order, would, therefore, occupy an interval of five seconds. At the conclusion of this fivesecond interval, the movable arms of all of the switches will be returned to the position shown in Figure 1 and at this instant further rotation of the motor 60 is stopped, unless. of course, another cycle of reverse slow motion is desired.

Naturally it is desirable that the cathode ray beams generated by the gun structures 50 be initiated sequentially and only during the interval that a charge image is to be placed on the asso ciated mosaic electrode. This interval for any particular storage tube will occupy M of a second. In order normally to render the electron gun structure 00 inoperative. a biasing potential source 80 is associated with each gun structure, the potential source being connected between the control electrode of each gun structure 50 and ground by way of resistance 82. The potential supplied by the source of potential 80 is sufficiently negative to bia the cathode ray beam to cutoff but in order that the cathode ray beam may be generated during and only during the desired interval, switches A and F are provided. The switch F is substantially identical to switch G while the commutator switch A is substantially identical to the commutator switch B. The 120 segments associated with switch A, and with which the movable arm of switch A co-operates, are connected respectively to the storage tubes 44, 45 46. The movable arm of switch A is then connected to the conducting segment 63 of switch F. This segment extends for a distance of 72 and the movable arm of switch F co-operates with this segment 68 during the one second storage interval; Av source of potential is connected between the movable arm of switch F and ground and the extent of this potential is sufllcient to overcome the biasing voltages from the source of potential 80. When the movable arm Of switch A is in contact with any one of the segments associated therewith, the storage tube connected to that segment is rendered operative and a cathode ray beam is generated in that tube in order that the image signals generated during that television frame cycle will be stored on the mosaic electrode of that particular tube.

A somewhat similar arrangement is also provided for removing the changing images in reverse sequence. The removal of the charges occurs at the normal television repetition rate in order that theslow motion illusion may be presented. The biasing of the electron gun structures 52 to such an extent that the cathode ray beams are not normally formed is accomplished by the potential sources 10 which are connected between the control electrode of each of the gun structures 52 and ground by way of resistances I2. The extent of thepotential that is applied to the control electrode of the gun structure I? is sufficient to bias the cathode ray beam to cutoff. For permitting a cathode ray beam to be formed in the proper storage tube at the proper instant. utating switch E is provided which makes one complete revolution in five seconds. This switch is provided with a 72 unused segment while the remaining circumference of the switch is provided with 120 contact segments which are connected individually to the control electrodes of the 120 storage tubes. These contacts are connected in reverse sequence to the tubes since inthe particular circuit arrangement reverse sequence slow motion television images are desired. After the one second storage interval the movable arm of switch E then first contacts segment I20 to permit the formation of a cathode ray beam in storage tube 46. In order to permit theformation of a beam the biasing potential 10 must be overcome and for this purpose a source of potential I4 is provided. The negative terminal of the source of potential 14 is connected to ground while the positive terminal is connected to the movable arm of the commutator switch E. It will be noticed that the commutator switch E is very similar to the corresponding switch D which is for the purpose light intensity; For increasing of sequentially connecting the collector anode 88 of the proper storagetube to the output circuit.

It is possible to derive the individual cut-ofl biasing potentials for the electron gun structures 58 and 52 of the storage tubes from a common source through individual high impedances with which the voltage maybe briefly and monentarily applied as described. There are many circuit modifications within the scope of this invention. It is also clear that the time constants of the various bias controlling circuits must be sufficiently short so that the bias changes occur so rapidly as not to cause undesired effects on the image sequences.

From the above, it may be seen, therefore, that motion which normally requires only one second to transpire may be presented in reverse sequence.0n the screen of a television receiver so as to occupy a time duration of four seconds. The presentation of the television images at the receiver occurs at the usual and normal television operating speed and it is, therefore, unnecessary to make any changes whatever in the television receiver. All of the apparatus required for producing reverse slow motion television images is located at the television transmitter.

When it is desired to present slow motion television images in reverse sequence it is only necessary to start operation of the motor .68 (preferablyv in the form of a synchronous motor) and continue the operation of the motor for the five second interval. In order to avoid the acceleration and deceleration effects of starting and stopping the motor 68, a clutch arrangement may conveniently be used so that the motor may be instantaneously clutched to or declutched from the various switches. 4 Appropriate time control of the operation of such a clutch is within the province of a skilled mechanic and need not be further shown or described herein. Once the switches are set in operation, image signals are stored on the image storage tubes for an interval of one second during which time the same motion is transmitted at normal operation speed. Immediately after the storage interval the slow motion presentation is effective to remove the stored charges in reverse sequence so that for the next four seconds a reverse slow motion effeet will be produced.

Theoretically, and in the absence of any ameliorating factors, at least four times the light intensity on the televised scene would be necessary for the production of slow motion television images, since the scanning rate is assumed to have been increased four fold and the charge storage time on the mosaic of the camera tube correspondingly diminished. The requirements for additional light intensity may be compensated for by uti-/ lizlng a faster lens associated with the slow motion television pick-up tube 38 or a more sensitive mosaic electrode could be used in that tube. In the absence of either of these compensatory measures, Figure 1 discloses an arrangement whereby two television pick-up tubes of substantially identical sensitivity may be used. The normal incandescent studio lights 16 are operated at rated voltage during normal television pick-up speeds and since the storage interval lasts for only one second these same incandescent studio lights may be operated at greater than their rated voltage with the result that they may be caused to produce approximately four times their normal the potential applied to the studio light I6, an auto-transformer 18 is provided. Thistransformer is associated with a single-pull-double-throw switch 88. When the switch is in the position shown the studio lights I8 are operated at normal rated voltage but when the switch 88 is in its raised position a higher voltage .is applied to the studio lights so that they may be operated as photo-flood lights to supplythe required additional illumination. For operating the' switch 88 during the prescribed interval an electromagnet 82 is provided and this electromagnet is operated by switch J and the source of potential 84. The movable arm of switch J co-operates with 72 conducting segment 86 to complete the circuit to the electromagnet during the one second storage interval so that the studio lights are over-excited during this interval only. This increased illumination would be considerably excessive insofar as the normal speed television pick -up camera I8 is concerned and since it-is desirable to transmit the television images in normal forward sequence concurrently with the storage of these signals, some provision should be made for considerably reducing the light intensity of the optical image projected on the mosaic I2 of the normal speed pick-up tube I8. For this purpose a translucent light'shutter 98 is provided which has a light transmission efliciency of approximately 25%. The translucent light shutter 88 may be operated by an electromagnet I88 and a co-operating magnet armature I82. As shown in the drawings, the translucent shutter is suspended by means of a spring or similar resilient member I84 so that it is normally outside the optical path. When the electromagnet I88 is energized the armature I82 is attached by theelectromagnet with the result that the translucent shutter 88 is interposed in the optical light path of a'normal speed pick-up camera I8, whichcompensates for the increased studio illumination. For operating the translucent shutter during the prescribed one second interval, switch H is provided and the movable arm of this switch co-operates with conducting Se ment I86 which extends for at least 72 around the periphery of the switch. When the movable arm of switch H is in contact with the segment I88, the electromagnet I88 is energized by means of the source of potential I88. Although separate switches H and J are provided, respectively, for decreasing the intensity of the image or pick-up tube It and for increasing the illmnination of the television subject. these two switches could be combined so that the same switch, and usually also the same source of potential, could be used for energizing the electromagnets 82 and I88.

. Alternatively, in order that the substantial and relatively intense increase in illumination may not effect persons being televised, it is also proposed to employ ultra-violet or infra-red light for the increased illumination assuming, of course, an appropriate color responsive mosaic is incorporated in the slow motion television pick-up tube 38. If the mosaic electrode in tube 38 were constructed to be exceedingly responsive in the ultra-violet spectrum, and if the mosaic in the normal pickup tube It had a spectral response similar to that of the human eye, then no switching arrangement would, in fact, be necessary since the ultra-violet light source could be left on continuously without in any wayafiording any discomfort insofar as persons being televised are concerned and without interfering with the illumination insofar as the normal pick-up tube I8.is concerned. The relatively intense ultra-violet illumination would be sufficient to permit operation of a slow motion pick-up camera tube 30. The required additional illumination, of whatever character-necessary or used for slow motion pick-up, may be turned on and oil automatically by a switchmechanically and electrically associated with either of switches H or J.

From the above it may be seen, therefore, that reverse sequence slow motion television images may be presented by utilizing the above de cribed circuit arrangement which is entirely confl ed to the television transmitter. The retardation ratio may be chosen at any desired value and furthermore the length of time that the slow motion presentation persists may also be altered as desired assuming similar commensurate alterations are made in the number of storage tubes used and in the arrangement and number of contacts that are associated with the various switches.

In addition to reverse sequence slow motion there may be instances when it is desirable to transmit television images in slow motion, first in a forward sequence and immediately afterwards in a reverse sequence. An arrangement for performing such an operation is shown, by way of example, in Figure 2. The circuit arrangement includes a normal speed television pick-up camera 2 Ill which supplies image signals through switch 2 to the television transmitter over conductor 226. A high-speed television pick-up camera 230 is also provided. For storing the images in order that they may subsequently be transmitted in slow motion in both forward and reverse sequence, 240 storage tubes are required with the illustrated example, rate and operational period.

For simplicity, these tubes are represented by the rectangles IF, IR, 2F, 2R 9F, IIQR, I20F and I20R. These tubes may be similar to the tubes 44, 45 and 48 shown in-Figure 1 and described above.

Associated with these tubes are switches K, L, M, N, O and P. The switches are operated in synchronism and inproper phase relationship with respect to each other by means of motor 260 which operates either directly or through gears at a speed of V revolution per second (75 R. P. M.). Accordingly, eight seconds is required for one complete revolution of the movable arms of switches M, N, O and P. Switches K and L, however, operate at eight times this rotational speed and one complete revolution of the movable arm of switches K and L is accomplished in one second. Switches L and P are utilized for storing the image signals on the various storage tubes while switch M is utilized for removing these storage signals in the desired sequence. In the present invention, as shown in Figure 2, television image signals produced by the normal speed camera 2 I are applied to the television transmitter along conductor 226. When it is desired to present slow motion television'images in first forward and then reverse sequence the motor 260 is started and is caused to operate for eight seconds. Simultaneously switch 2 is placed in its upper position. For simplicity, the actua1 means for operating switches 2I I is not shown but some means similar to either switches H or J shown in Figure 1 may be used.

Switch P includes a movable arm which cooperates with conducting segment 262. This segment extends around the periphery of the switch for a distance of approximately 45. The extent of the conducting segment 262 is a motion of the retardation ratio chosen for the slow motion images, but in describing this particular circuit arrangement it is assumed that a retardation ratio of four is used and that motion which normally transpires during a one second interval is presented in slow motion for four second in a forward sequence and for a corresponding length 5 of time in reverse sequence. With these assummed values the length of the conducting segment 262 should be 45.

Televislonimage signals are obtained from the high speed television pick-up camera 230 are applied to the movable arm of switch P and when this arm is in contact .with segment 282 the same signals are applied to the movable arm of switch L. The commutator switch L includes 120 peripheral conducting segments each of which is associated with a different pair of storage tubes. For example, contact I of switch P is associated with the second anode (or corresponding electrode) of storage tubes IF and IR. Similarly, contact 2 is associated with the corresponding electrodes of tubes 2F and 2R. Accordingly, when the movable arm of switch L rests on a particular conducting segment, the two tubes connected to this segment are supplied with image signals so that these signals may be stored on the storage electrodes contained in these tubes. It may be seen, therefore, that as the movable arm of switch L makes one revolution (one storage interval) all of the storage tubes will have been provided with television image signals in proper sequence. At the conclusion of the one second storage interval, the movable arm of switch P leaves conducting segment 262 and interrupts any further application of television image signals to the movable arm of switch L. Further rotation of the movable arm of switch P is of no consequence.

As soon as the storage interval begins, movable arm of switch M is displaced in the direction shown from itsnormal position to contact in sequence the 240 conducting segments of switch M. These 240 conducting segments are individually associated with the 240 storage tubes and the connection is such that the stored signals will be removed first in a forward sequence and immediately thereafter in a reverse sequence. Since the forward sequence was chosen first, transmission of the slow motion images begins immediately at the start of the storage interval with the result that the stored images are removed in sequence from storage tubes IF, 2F, etc., through 50 IISF and IIIIF. After the stored images have been removed and transmitted in a forward sequence, the movable arm of switch M then cooperates consecutively with storage tubes I20R, II9R, etc., through 2R and IR. During this time, slow motion television images will .be presented in reversesequence, the entire slow motion presentation occupying an eight second interval. At the conclusion of this time switch 2 is placed in its lower position so that the normal speed television pick-up camera, 2III may then supply signals to the television transmitter.

The television image storage tubes should be effective and operable only during the desired interval and accordingly it is desirable to provide some means for preventing the production of a cathode ray beam in these tubes except during these desired-short intervals. For preventing the formation of an electron beam, biasing potentials may be used such as those shown associated with tubes 44, 45 and 46 in Figure l (but not shown in Figure 2). For overcoming these biasing potentials switches K, N and O are employed. Switch K, for example, includes 120 conducting segments each of which is associated with the control electrodes of thegun structures of a partlcular pair of the storage tubes. The movable arm of switch-Kis connected to conducting segm'ent268 which extends for a distance-of approxir .ately 45 around the periphery of the switch.

The movable arm of switch isthen supplied with a source of potential from the battery or similar potential source 290. By means of the operation of switches O and K, cathode ray beams are caused to be generated in the storage tubes in the desired sequence,

For permitting the formation of a cathode ray beam for the removal of the stored charges, selector switch N is provided which includes 240 contacts arranged around its periphery. A source of potential is applied to the movable arm of this switch from a potential source 214 so that the necessary unblocking potentials may be applied to the control electrodes of the various storage tubes in the desired sequence. The operation of switches O, K and N are similar to the operation of switches F, A and E, respectively,

of Figure 1.

and this may be accomplished by increasing the illumination supplied by the studio lights 216. These lights may be operated from an autotransformer 218 in conjunction with singlepole-double-throw switch 288. For simplicity, switches 2H and 288 are shown as mechanically connected together so that when the switch! is placed in its upper position to store image signals and to derive slow motion television image signals from the movable arm of switch M, the studio lights 216 will simultaneously be increased in intensity. Since it is not necessary for the studio lights to be over-energized for a time exceeding the one second storage interval, the mechanical connection of these switches, 2H and 288, could be dispensed with and a switching arrangement such as shown at J in Figure 1 could be used instead.

Since, in Figure 2, normal motion television image signals are not transmitted simultaneous with the storage of image signals representing the same motion, it is not necessary to protect the normal speed television pick-up camera 2H! from the increased illumination as was the case in the circuit arrangement shown in Figure 1 and described above.

From the above it may be seen that by utilizingthe circuit arrangement shown in Figure 2, slow motion television signals will be transmitted first in normal sequence followed immediately by transmission of the same subject matter or motion in a reverse sequence. At the conclusion of the slow motion transmission normal forward motion is automatically resumed.

It is possible materially to simplify the slow motion circuit arrangement described above and to reduce the scanning speed in the normal pickup tube if each television frame from the slow motion pick-up tube is applied simultaneously to four of the storage tubes (eight in the case of Figure 2) so that the same electrostatic charge image is deposited on groups of four of the storage tubes simultaneously. The same image could then be scanned as described above at the normal rate to produce an apparent slowness of motion. Such a system, although physically simpler in so far as scanning and switching is concerned, is not so desirable, since the resultant images may be jerky in their motion and not have an apparently smooth reproduction as is the case where multiple speed scanning: as previously described herein is employed. Where each television frame image in slow motion is stored on four storage tubes, the same detail of movement cannot possibly be presented as will be the case if a; system such as shown and described above is employed;

Although timers-and commutators of a mechanical nature are shown and described herein, it is to be understood that electronic switching means could as well be employed for accomplishing the same purpose. Mechanical switching arrangements have merely been shown in order to simplify the drawings and explanations thereof and in order to'present readily a complete and understandable description of the operation of the slow motion television system. Furthermore, it is to be understood that various types of television pick-up tubes may be used, and that it is not necessary to use the particular form of electron storage type specifically indicated in the drawings. Furthermore, various types of storage tubes may be used, the ones shown being merely representative of various types that could be em-' ployed.

Various other alterations and modifications may be made in the present invention, and it is desired that any and all such modifications be considered within the purview of the present invention except as limited by the hereinafter appended claims.

Having now described my invention what I claim is:

1. A reverse slow motion television transmitting system comprising a television pick-up tube including a target electrode, means to generate a cathode ray beam, means to deflect the cathode ray beam in mutually perpendicular directions to scan the target electrode at a predetermined rate to produce image signals representative of a sequence of individual complete images, a plurality of storage tubes each including a storage electrode, means to store the produced image signals, in normal sequence, on the storage electrodes of said tubes as electrostatic charges, and means to remove the stored image signals as a reverse sequence of complete images and at a rate that is slow as compared to their originally produced rate.

,2, A reverse slow motion television transmitting system comprising a television pick-up tube including a light-sensitive target electrode, means to produce an electrostatic charge image of a scene to be transmitted on the target electrode, means to generate a cathode ray beam, means to deflect the cathode ray beam in mutually perpendicular directions to scan the target electrode at a predetermined rate to produce image signals representing each television frame, a plurality. of storage tubes each including a'storage electrode, means to sequentially store the roduced image signals on the storage electrodes of said tubes as electrostatic charge image replicas of the image scanned in the pick-- up tube, and means to remove, in reverse frame sequence, the stored image signals at a rate that is slow as compared to their originally pro duced and stored rate.

3. A reverse sequence slow motion television transmitting system comprising a television pickup tube having a light-sensitive target electrode, means to generate a cathode ray beam in said tube, means to'deflectthe'cathode ray beam in horizontal and vertical directions to scan said target electrode to produce image signals corresponding to each television line and frame, a plurality of storage tubes each including an electron storage electrode, means including a switching arrangement to sequentially storethe produced image signals representative of' each television irameon aseparate storage tube, and means including a second switching arrangement to remove the stored image signals in reverse frame succession at a rate that is slow as compared with the rate at which they were originally produced and stored.

4. A slow motion television. transmitting system comprising a television pick-up tube having a target electrode, means to generate a cathode ray beam in said tube, means to deflect the cathode ray beam-to scan said target electrode to produce image signals corresponding to each television frame, a plurality of pairs of storage tubes each including an electron storage electrode, means including a switching arrangement operable to sequentially store the produced image signals on the storage tubes inpairs, means including a second switching arrangement operable to successively remove the stored image signals from one-of each pair of storage tubes in their stored sequence' and to subsequently sequentially remove the stored image signals from the other of each pair of storage tubes in reverse frame sequence, the removal rate being slow as compared with the rate at which they were originally roduced and stored.

5. A reverse sequence slow, motion television transmitting system comprising a first and a second television transmitting pick-up tube, each including a target electrode and means for developing a cathode ray beam, means to deflect the developed cathode ray beam in the first pick-up tube to scan its target electrode at a first predetermined'rate to produce image signals, means to deflect. the developed cathode ray beam in said second pick-up tube to scan its target electrode at a second predetermined rate to produce image signals corresponding to each succesive televisionv frame, the said second scanning rate being considerably faster than the said first scanning rate, means to directly transmit the image signals produced by said first pick-up tube, a series of television picture storage tubes, means to store in said storage tubes the image signals produced by said second pick-up tube at their rate of production, and means to subsequently remove and transmit, in reverse frame sequence, the stored image signals at a rate corresponding to the rate of transmission of said picture signals from said first pick-up tube.

6. A slow motion television transmitting system comprising a television transmitting pickup tube including a, target electrode, means for developing a cathode ray beam in said tube to scan the target electrode at a predetermined rate to produce image signals corresponding to each television field, a series of pairs of television image storage tubes, means to sequentially store the produced image signals representing the television fields as charge images in said storage tubes, in pairs at their rate of production, and means to remove the stored image sig nals from one of each pair of storage tubes in one predetermined field sequence and ,to subsequently remove the stored image signals from the other of each pair of storage tubes in a different predetermined field sequence, the rates 01' removal being slow as compared with the assnoos rate at which they were originallyproduced and stored.

7. A reverse sequence slow motion television transmitting system comprising a first and second television pick-up tube, each including a target electrode and means to'developva-cathode ray beam, means to deflect the developed cathode ray beam in said first pick-up'tube at a predetermined normal rate to produce image signals representing a predetermined interval of motion, means to deflect the developed cathode ray beam in said second pick-up tube at a rate considerably in excess of the normal rate to produce image signals representing television fields of the same predetermined interval of motion, a plurality of electrostatic charge storage tubes, .means to utilize the image signals from said first pick-up tube, means including a switching arrangement for concurrently storing, in said storage tubes, the image signals produced during the predetermined interval by said second pick-up tube, means including a second switching arrangement for subsequently removing, in reverse field sequence, the stored image signals at the said predetermined normal rate, and means to utilize the removed image signals.

8. A television transmitting system including means to convert a series of optical images into a series of image signals, a plurality of pairs of electrostatic charge storage elctrodes, means to sequentially produce, in pairs, on the storage electrodes, a series of electrostatic charge images representing television frames in response to the produced series of image-signals, means to subsequently scan one of each pair of the charge storage electrodes in a predetermined frame sequence to produce another series of image signals, and means to further subsequently scan the other of each pair of the charge storage electrodes in a different predetermined frame sequence to produce still another series 01' image signals.

9. A television transmitting system including a plurality of pairs of charge storage electrodes of mosaic construction capable of retaining a plurality of separate elctrostatic charges on the elemental areas of each eelctrode, means to sequentially produce, from a succession of optical images, an electrostatic charge image on each pair of electrodes at a predetermined rate, means to subsequently onvert the electrostatic charge images on one of eachpair of the storage electrodes into a series of image signals, and means to further subsequently convert the electrostatic charge images on the other of each pair of the storage electrodes into another series of image signals, the conversion rates being different from the rate at which the electrostatic charge images were produced on the charge storage electrodes.

10. A television transmitting system comprising a first television pick-up tube for converting optical images of a subject matter into a series of image signals at one predetermined rate, a second television pick-up tube for converting optical images of the subject matter into a series of image signals at a different predetermined rate, means to transmit directly the image signals produced by said' first pick-up tube, a series of pairs of television image storage tubes, means to store, in pairs, in said storage tubes the image signals produced by said second pick-up tube at their rate of production, means to remove and transmit the stored image signals from one of each pair of storage tubes at a rate corresponding to the rate of transmission of the image signals from the first pick-up tube, means to subsepick-up tube, and means associated with the optical system of the first pick-up tube for compensating for the alteration in the charge of i1- lumination of the subject matter.

11. A television transmitting system including means to convert a series of optical images into a series of image signals at a predetermined rate, a plurality of pairs of-electrostatic charge storage electrodes, means to sequentially produce a series of electrostatic charges representing television images on the storage'electrodes, in pairs, in response to the produced series of image signals, means to scan one of each pair of the charge storage electrodes in a predetermined image sequen c and at a rate different from said predetermined rate to produce another series of image signals,

means to scan the other of each pair of the charge storage electrodes in a different predetermined image sequence and at said diiferent rate to produce still another series of image signals, and means to utilize the produced series of image signals.

12. A television transmitting system including a plurality of pairs of charge storage electrodes capable of retaining a plurality of separate electrostatic charges on the elemental areas of each electrode, means to sequentially produce, in pairs, an electrostatic charge image representing television frames on said eelctrodes at a predetermined rate from a succession of optical images,

means to convert, in a predetermined frame sequence, the electrostatic charge images on one of each pair of the storage electrodes into a series of image signals, and means to further convert, in a difierent predetermined frame sequence, the electrostatic charge images on the other of each pair of charge storage electrodes into a different series of image signals, both conversion rates be ing identical but different from the rate at which the electrostatic charge images were produced on the charge storage electrodes,

13. A television transmitting system comprising a first television pick-up tube for converting optical images of a subject matter into a series of image signals at one predetermined rate, a second television pick-up tube for converting optical images of the same subject matter into a series of image signals at a different predetermined rate, means to transmit directly the image signals produced by said first pick-up tube, a series of television image storage tubes, means to store in normal television field sequence, on said storage tubes the image signals produced by said second pickup tube at their rate of production, means to remove and transmit, in reverse television field sequence, the stored image signals from the storage tubes at a rate corresponding to a rate of transmission of the image signals from said first pickup tube, means to illuminate the subject matter, means to alter the illumination of the subject matter during periods of operation of said second pick-up tube, and means associated with the optical system of the first pick-up tube for compensating for the alteration in the charge of illumination of the subject matter.

ALFRED N. GOLDSMITH.

Images