US1699222A - Transmission of pictures - Google Patents

Description

Jan. 15, 1929.

C. A. CLARKE TRANSMISSION .OF PICTURES 2 :ShoctsShoot l la er/fan" Filed Aug. 8, 1925 Cara/e A 6700?! 1 4 17/};

Jan. 15, 1929.

c. A. CLARKE TRANSMISSION OF PICTURES Filed Aug. '8, 1925 2 Sheets-Sheet 2 Patented Jan. 15,1929.

uNirEo STATES PATENT OFFICE.

canon: a. enema, or MONTREAL, QUEBEC, enema, assrcnon r wnsrnmw mewe comm, mconrom'rnn, or NEW YORK, 1v. 2., a conroaurron or new YORK.

TRANSMISSION OI IICTURES.

Application med August a, 1925. Serial No. 48,989.

This invention relates to transmission systems'and more particularly to the transmission of pictures by electrical means.

In the transmission of pictures, 1t has been found necessary and desirable at times to transmit the same picture a number of times .to various stations and over different transavailable at any maintain a file of pictures availablefor immediate use at a central station or in case lines or channels or. at different speeds of adequately suited to any particular signal-'- ent invention pictures are to be retransmitted from a central distributing station over a number of transmission. This will enable the operator at the distributing station to transmit over any available transmission channel or to adapt the speed of transmission to that most mg circuit.

Obviously, considerable saving of time re-. sults from the use of such a method as it eliminates the procedure of photographing the subject to be transmitted and the operations incident to its being made suitable for 1 i For the purposes of this case it has been transmission purposes.

'One of the principal objects of the. presis the recording of signals for retransmission. 1 1

Another object of the invention is there'- nals to reproduce a picture at a distant sta tron. i In methods of carrier j current picture transmission heretofore developed, the reproduced picture is .a good reproduction of the original, but if magnified, it will be seen that the variations in tone value at the carrierfrequency are not sinusoidal in character. In order to retransmit such a'picture it must be treated as was the original. In accordance with this invention the variations just mentioned. are made to beef, a sine wave character andan electric ,carrier wave, of sine form 18- generateddirectly therefrom -for retransmissionpurposes. :It -isa further object of this inventionto produce a record from which a sinusoidal carrier wave may be directly produced' According to one embodiment of the invention the characteristics of each elemental area of a picture are transmitted as modula tlons of a voice frequency carrier wave whlch can be readlly transmitted over ordi-Y nary telephone lines. The modulated carrler wave is impressed at the distant station on an electrical recorder which functions to .record not only the carrier wave modulated in accordance with the tone values ofthe picture, but also a carrier wave to be later invention will be illustrated and described as employed in connection with a picture transmission system such as that disclosed in Patent No. 1,606,227, issued November 9, 1926, to Messrs; Horton, Ives. and Long.

thoughtsuflicient to show only so much of the ,apparatus and mechanism disclosed 1n that application as is necessary to a clear and accurate understanding of the present invention. 1' Referring novr'to the drawing:

Fig. 1 illustrates one form of sending equipment of a picture transmissionsystem connected by means of any-suitable trans mittin mediumj to a recording mechanism locat at a distant station. n

mechanism at a distant station 'for retransmitting stored si nals.

Fig. 2 illustrates one form-of reproduciug f I Fig. 3 is a si e view of the; recording mechanism.

' Fig. 4 is a corresponding f view of the re- .5

producing mechanism.

Fig. 5 is a 'circui diagram illustratinga further use of the invention. 7

Referring now to 1, station A although the invention is capable of use in connection with radio oinanyother electrical signaling system. At station A there is locatedsuitable mechanism for the trans mission of carrier current waves modulated in accordance with the tone values of the elemental areas of a picture to be transmit ted. At station B, there is shown an electrically opera-ted recorder which responds to the carrier current waves transmitted from station A for recording on a record representations of the transmitted carrier cur rent Waves. The record shown is in the formof a wax cylinder and is preferably of the type in which the impressions in the wax are lateral cuttings as distinguished from the hill and valley type of record.

At station A a modulator 6 is supplied with carrier waves from a carrier oscillator 7' and with picture current from a photoelectric'cell 8. For the purpose of clearness the modulator is shown in conjunction with an amplifier serving to amplify the picture currents before being impressed on the modulator. Modulated carrier waves from the modulator 6 are impressed upon the telephone line 10 through a picture channel filter 9 and a terminal repeater 11.

The photo-electrc cell8 is located within a transparent drum 14 which is driven by a shaft 15 to which it is rigidly secured. The shaft 15 is journaled in a carriage 16 slidably mounted upon a stationary raclr 17. Secured to the shaft 15 is a gear wheel 18 which meshes with the teeth of a gear 19 secured to a shaft 20. The shaft 20 is threaded for a portion of its length and engages threads formed in one of the uprights 16 so that upon the rotation of shaft 20, a rotary and a lateral movement is imparted to the drum 14. Motive power is supplied to the shaft 20 from amotor 21 preferably of the phonic wheel type through a friction clutch or starting mechanism 22. The starting mechanism 22 is arranged to control the engagement and disengagement of the parts of the friction clutch, thereby controlling the starting and stopping of the I transparent drum 14."

Mounted on the transparent drum 14 is a transparent film of the picture to be transmitte Light from a source 30 is focused by means of a' lens 31 upon the film through whichdt' passes to the photo-electric cell 8. The amount of light affecting the photoelectric cell 8 is determined by-the light density of the elemental area of the film which is at that instant in alignment with the light source 30. The amount of light falling upon the hoto-ielectric' cell 8 in turn determines t e amount of current which is supplied to the amplifier modulator 6 and in consequence, the value of current impressed on the line conductors 10, or in other words the amplitude of the carrier wave. The master fork 25 not only serves to control the current driving the motor 21 but also serves to control the application of a separate and distinct synchronizing current wave through control channel filter 27 and the terminal repeater. 11 on the condtictors 10 extending to station B.

The modulated picture carrier wave and the synchronizing carrier wave traverse the line 10, the terminal repeater 33 and the amplifier 34 and are impressed directly on the operating coil 35 of the electrically operated recorder 36.

Referring now for the moment to Fig. 3, there is shown diagrammatically, an electro magnetic phonograph recorder having a per-- manent magnet 38, although an electromag' net may serve equally well. Secured to the magnet 38 are soft iron pole pieces 39-l-0 and 4142, preferably laminated, with beveled ends between which is pivotally supported an armature 43, tapered at each end to 'reduce its mass. The armature i3 is mounted on an elongated bar it preferably of a suitable aluminum alloy and is provided with recesses for receiving knife edges upon which it is mounted. The bar 14 is held on its pivots and the armature l3 balanced preferably by means of a resilient support- The bar aid is turned at right angles and has secured to its other end a stylus holder QT in which is mounted a stylus cutter 48.

For further details concerning the construction and operation of the recording, mechanism just described, reference should he had to Patent No. 1,663,884, of H. C. Harrison, issued March 27, 1928.

The stylus cutter 48 engages a wax record blank 50 which is supported by a drum 51 to which power is communicated from motor 52.

Referring to Fig. 2 the mechanism for retransmittmg the reproduction of the matter recorded on the record 50, the transmission of current characteristics over the telephone circuit 59 in accordance with the cuttings on the record and the reproduction of the picture at a distant station'will now be described. As shown in Fig. 2, the reproducing mechanism.55, which may be of a similar construction to that previously de- V imam This may beithesiame speed as the speed of the motor driving the cylinder during the recording operation or some otherspeed different from the speed at which the picture was originally recorded as will be pointed out later. Withthese conditions satisfied the carrier current waves representing'not only the'modulated output carrier current wave but also the synchronizing current wave will be impressed on the line conductors 59 extending to station C.

The impulses upon being received at sta-' tion C pass through a terminal repeater 67 and are impressed on the picture channel filter 68 ,and the control channel filter 69. Each of these two filters passes only a particular frequency which performs the desired function. The current passed by the control channel filter is amplified and rectified by means of an amplifier-rectifier 70 and impressed on a secondary fork or speed control element 71. The secondary fork 71 thus operates at a definite speed ratio with reference to the master-fork located at release of the. startin station A and serves to drive the motor 72 so that the recording drum will rotate at the desired speed. s

Similarly, the motor72 is connected with the, reproducing mechanism 'through astarting mechanism 73. The starting mecha- IllSIIl 73 is preferably the same as'that described at station A. Since this particular part does not form a part of the present invention, further details thereof are believed unnecessary.

The drum 65 which is driven from the motor 72 throu h suitable gears has mounted thereon a p otosensitive surface or film 66. Connected to the picture channel filter 68 is an amplifier 74 servin to control the mec anism 73 and the operation ofa suitable light valve 75. The light valve controls the amount of light fallingcn the sensitive surface 66 from a light source 76 in accordance with the signals received thus reproducing the picture.

The operation of the system will now be described. Assume that's, transparency 29 of a picture to be transmitted has been secured to the drum 14. When it is desired to start the transmission, suitable mechanism is operated for releasing the starting mechanism 22. .The operation of this mechanism not only releases shaft 20 for rotatiombut also transmits to station B a carrier current .wave which is im ressed on the electrical recorder 36 and w 'ch is recorded on the record 50. The drum 14 and the trans arent film are now rotated and moved axially by means'of the motor 21 whichis driven from the master foil: 25. Carrier current modulated in accordance with the current anpressed on the amplifier-modulator 6, as determined by the condition of the photo-electric cell 8, passes through the picture channel filter 9 and is impressed on the terminal repeater 11. Simultaneously, with the im-.

pression of the picture carrier current wave on the terminal repeater 11, a second car-- rier current wave of a different frequency, as determined by the control channel filter 27, is impressed on the terminalrepeater.

The two carrier current waves are transmitted over the line conductors 10 to station B where they pass through theterminal repeater 33 and amplifier 34 and are impressed on the control-element 35. of the electransmitted to the station B and permanently recorded on the record blank 50.

Assume for example, that it is desired to transmit a picture in accordance with the one previously recorded on the record blank 50 to a distant station C.- The record blank 50 is accordingly secured to the drum 56 which is driven by the motor 57. The motor is now started and'the stylus 58 allowed to traverse the cuttings in the record 50. The

operation of thestylus 58 causes the conversion' of the mechanical movements thereof.

through the action of the coils 45 and 46 into electrical energy having the same characteristics as that controlling the recording-opera 165 tion. Carrier current waves are accordingly impressed on the line conductors 59 throng an amplifier 60 and a terminal repeater 61. The impulses received at station 0 from line conductors 59 pass through terminal repeater'67 where they divide, the picture carrier current passing through the picture. channel filter 68 while the synchronizing carrier current passes through the filter 69. At the beginning of the record 50 as previously described, there is recorded a control frequency current which acts on the ampli* fier'74 to cause the o eration of the starting v mechanism 73 for re easing the drum 65 for rotation. The picture carrier currents are amplified by means of the amplifier 7 4 and impressed on thelight valve-7 5 which controls the exposure of the various elemental areas of the light sensitive surface 66 1 n accordance with the tone values of the original picture, The synchronizing carrier current waves are amplified by means-of the amplifier. 70, and control the secondary fork 71' so that the motor 72 rotates and moves the drum 65 at the same speed relative to the speed of picture signal transmision as that at which the drum 14 located at station A moved. Consequently, the respective ole mental areas of the light sensitive surface 66 will be accordingly arranged and exposed to faithfully reproduce the original picture.

The speeds of recording and retransmitting signals do not necessarily bear any relation to each other as it is possible to receive signals at one speed and retransmit at some other speed as desired, providing the reproducing drum is rotating at a correspondingly different speed. For example, a transmitting cylinder at station it. may be rotating at a speed ct one revolution per second and signals may be transmitted with a 1300 cycle carrier. at the receiving station the recording element mayrotate at the same speed or slower or faster as desired. But continuing the example, we may consider that the recording drum rotates at hall the speed the transmitting cylinder, that is, once every two seconds. or once for each two revolutions of the cylinder at station A. This is possible since the special relation of the signals on the record is immaterial, the proper sequence only being necessary. It now in retransmitting the signals the record is rotated at one revolution per second which is twice its recording speed, the signals will be transmitted to the line at twice the original speed of recording and the carrier will appear as 2600 cycles per second instead of l300'cycles as originally transmitted from station A. If. however,

there is no transmission channel available for transmitting 2600 cycle modulated carrier, the speed of the record may be in.- creased or decreased to any desired speed in order to make use of an available channel or to transmit signals at a "frequency at which the particular transmission channel is most elficient. The recording element may therefore receive and retransmit at any speeds whatever so that signals can readily be transferred from carrier frequency to voice frequency or vice versa or may even be transmitted at speeds suitable for cable transmission;

While the invention has been described as suitable for recording simultaneously both picture signals and synchronizing signals it maybe desired to transmit either type of signalby'itself. In this case the danger of interference betweenthe picture signals and 1 svnchronizing signals will be eliminated.

' The picture transmitting drum may then be rotated by some constant frequency motor and thevspeed ofr'otation indicated to station B so that on" retransmission it will sim-' ply be necessary to tell the operator at station (1 the ratio'of the speed of the recorded signalsto-the transmitted signals in As illustrated inFig. 5 a number of sepa-;

rate sets of picture transmission apparatus may be connected to the same line for trans mitting more than one picture at a time or forsimultaneously recording severalpictures on one record for simultaneous retransmission. For this purpose two sets of transmission apparatus and 83. which are preferably the same as that included within the dotted rectangle of Fig. 1, both transmit signals impressed to the same line L through terminal repeaters 81 and 84 and filters 82 and 85. The two series of signals will of course be transmitted as modulations of different frequency carrier waves. As shown the synchronizing signal oscillator and filter have been omitted but it is equally possible to operate the system including the synchronizing channels. According to this system of operation the signals from both on separate records. Such a system is particularly adapted for use in transmitting colored pictures in the form of three color records.

Although the invention has been described and discussed with reference to a particular system, it should be understood that the invention is not limited to use with the particular apparatus illustrated, but may be used in connection with the recording and retransmitting of any type of electrical signals.

The term light, as used herein includes not only radiations within the visible'spectrum but also radiations having wave lengths above and below those of the visible spectrum.

It is to be understood that the terms used herein in reference to picture transmission,

.bothin the specification and claims, do not limit this invention to the production of a picture record at the receiver from 'a picstill or moving picture or object is produced at the receiver, as in certain forms of tele- I vision systems.

What is claimed is: 1. In a picture transmission system, means for producmg a record 1n accordance with modulations of'a'carrier wave as determined by the elemental tone values of a picture or object and in accordance with a separate'carrier wave, a transmission line, and means associated with said line for reproducing from said record electrical variations of the same forms as. those of said record.

neeaaaa 2. In a picture transmission system, means for transmitting a. carrier wave modulated in accordance with the tone characteristics of a picture or object, means for recording said carrier wave on a record blank 1n the form of a single continuous impression, and

a reproducer for retransmitting the carrier wave ln accordance with the impression on said record blank.

for converting electrical variations into mechanical vibrations in accordance W1tl1 the elemental tone values of a picture or chject a receiving surface, means for causing sa1 vibrations to effect an impression on said surface to correspond to said electrical variations, a transmission line, and an electrical .reproducer for transmitting vtosaid line a carrier wave of the form determined by the impressions on said surface.

4. In a picture transmission system,.means for modulating a carrier current in accordance with elemental tone values of a picture or object, a line, means for impressing said carrier cuig'ent on said line and for simultaneously impressing on said line a synchronizing carrier current, a receiving station with a receiving surface associated with said line, and means at said station responsive to .the transmission of said carrier currents over said line for producing a continuous impression in said surface corresponding to the transmitted carrier currents.

5.In a picture transmission system, a transmission line, means for simultaneously impressing on said line picture currents and synchronizing currents, and means for receiving said currents and recording the same in the form of a single continuous wave of substantially sine form.

' 6. In a signaling system, a transmitting medium, means for simultaneously impressing a plurality of carrler waves of diflerent frequencies on said medium, a receiving sur-[ face, and means for recording said simultaneously transmitted waves as a single continuous variation in said surface.

7.. In a picture transmission system, means for making a record'in'the form of a single continuous wave of combined picture and synchronizing currents, and means for reproducing a picture from said single wave record.

8. In a signalingsystem, sending appalratus, receiving apparatus, means for s multaneously sending picture currents and synchronizing currents, means for making a record inthe ,form of a "single continuous wave of the combined synchronizing and picture, currents, andmeans for reproducing a or picture on apparatus 3. In a picture transmission system, means my name thisthir'd 192 5.

control of said single continuous wave record. I 9. In a signalingsystem, sending apparatus, receiving apparatus, means for transmittin from said sending apparatus at a desire nizing currents, means for making a record of the combined signaling and synchronizing currents, means controlled by said record for retransmitting said currents at any defrequency, signaling and synchro-' sired frequency, and means controlled by said ing at an desire speed a single mechanicalrecordo the combined currents, means for retransmitting said combined currents under control of said record at any speed determined by the transmission line characteristics, and means. for reproducing a picture from said retransmitted currents. y

12. In a picture transmission system, means for producingrpicture currents in accordance with the characteristics ofa picture or object, a source of carrier current of a particular frequency, means for modulating the current from said source by means of the picture currents, means for making a. record of the modulated carrier current, means controlled by the form of said record for reproducing a modulated carrier current of any desired frequency, and means-controlled by said reproduced current for reproducing said picture. I. I

13. In a picture transmission .system,

means for producing at a particular fre- 'quency currents varying in accordance with the characteristics of a picture orobject, a receiving surface, means for changing said current variations into mechanical vibra-- I roduce'a record thereof in the substance 0 said receiving surface, a current tions to generator controlled by said record for reproducing said current variations at any desired frequency to re roduce said picture.

In witness whereof I hereunto subscribe 5 CAROLE e.

day, of August D.,

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