US2079880A - Television transmission method - Google Patents

Description

G. SCHUBERT 2,079,880

TELEVISION TRANSMISSION NETHOD May 11, 1937.

Filed June 27, 1935 lnventor:

Patented May 11, 1937 UNITED STATES PATENT OFFICE firm Fernseh Aktien -Gesellschaft, Zehlendorl,

near Berlin, Germany Application June 2'7,

1933, Serial No. 677,932

In Germany June 30, 1932 6 Claims.

This invention relates to atelevision transmission method intended primarily for the transmission of animated scenes, in which transmission is performed with the assistance of an intermediate record prepared on a normal motion picture film. Immediately following exposure the film is developed in a rapid developer and passed through a transmission apparatus, which performs the transmission within a very few seconds after the actual incident has taken place.

I have already describedv a method of this nature in my copending patent application Ser. No. 641,092 filed Nov. 3, 1932.

In order to televise a scene of long duration without interruptions it would be necessary to employ film reels of correspondingly large size. Thus, for example, for a transmission lasting 30 minutes approximately 3,000 feet of film would be required. Although this to a certain extent will be found sufllcient for the transmission of short scenes, it may nevertheless be desired or necessary that transmissions of greater duration are provided. In this case it would be necessary to introduce relatively long intervals into the transmission for the purpose of exchanging the film reels and inserting the new length of film into the transmission apparatus.

It is the object of the invention to overcome the drawback in question, and this is accomplished by the use of two transmission apparatus operating alternately. When changing over from one apparatus to the other, care must be taken above all that the transmission of the image continues in the same phase as in the apparatus which has been disconnected, as otherwise a readjustment of the phase of alLreceivgrs will be necessary.

This problem may be solved in different ways. Preferably the procedure will be such that the transmission apparatus 200 is set into operation a certain time before disconnection of the transmission apparatus I00, and in the first place acts on a control receiver, which runs absolutely synchronously with and in the same phase as the control receiver pertaining to the transmission apparatus I00. Assuming, for example, there is employed as control receiver a receiver of the Nipkow disc type, the mode of operation for this purpose may be such that the operating motor for the control receiver belonging to the apparatus I00 is coupled by means of a flexible shaft with the operating motor for the control receiver belonging to the transmission apparatus 200. In this case the discs runabsolutely synchronously and with equal phase.

A more simple method consists in mounting the two Nipkow discs, which serve for composing the two received images, on a common shaft, and in this way combining the control receiver of the apparatus I00 with the control receiver of the apparatus 200. It is, however, also possible to use only one Nipkow disc if, for example, the same is provided with two spirals and supplies two control images simultaneously, of which admittedly one is somewhat larger than the other. Complete equality in the size of images may be obtained by corresponding adjustment of the optical enlargement means. is possible to work with control receivers of other systems which for example employ Braun tubes.

The change over from the transmission apparatus I 00 to the apparatus 200 takes place in such form that, asalready described, the apparatus 200 is set into operation a certain time before the apparatus I00, is disconnected the apparatus 200 produces now at the control receiver an image, the phase of which initially is not correct in relation to the image supplied by the apparatus I00. In order to equalize the phase of the two images .it is necessary to vary the phase of the filmadvancing motor of the apparatus 200 until the phase of the two control images is exactly the same. As soon as this condition has been attained the apparatus I can be disconnected, and there the apparatus 200 is employed for modulation of the wireless. transmitter. This change over operation-will hardly be perceptible by the person at the receiving end.

In order to make the disconnected apparatus I00 again ready for operation with the least possible delay it is desirable to disconnect this apparatus at the moment when the end of the film leaves the supply reel so that a new film may be secured to the end of this film before itis drawnthrough the various parts of the apparatus. There is always a certain length of film present in the complete transmission apparatus, 1. e., in the camera, the lightproof apparatus for developingand fixing the film, the image-scanning apparatus and the various passages or ducts connecting these parts. This piece of film situated in the apparatus may be -25 feet long. If now special precautions were not taken, it might happen that upon disconnection of the apparatus I00 the end of the film runs into the one or the other apparatus serving for the photo-chemical processes or into the image-scanning apparatus.

This is extremely undesirable, because it would then be necessary to thread the new film manually through the entire apparatus, which is a very tedious operation,as it is necessary to open both In similar manner it the camera as well as the developing and fixing apparatus in order to pass the film through the different guiding elements, which in part are situated in liquid. The film also would have to be introduced into the operating and guiding elements of the image-scanning device, and secured to the hub of the storage reel. Since this manual threading operation moreover is accompanied by a readjustment of all film wiping means, a considerable time would elapse before the apparatus is again ready for use.

To avoid these difiiculties the apparatus I00, according to the invention, is stopped shortly before the end of the film leaves the supply drum, and the leading end of the new film is connected with the end of the old film, by the usual cementing process. In this manner a manual insertion of the new film is avoided, as the end of the old film guides the leading end of the new film automatically into the apparatus. Proper use of this method however depends upon careful attention on the part of the operator, who also has to start the apparatus 200 in good time before the film in apparatus I00, is exhausted. Simultaneously with the disconnection of apparatus I00 the transmission apparatus 200 must be switchedover on to the amplifier. Even assuming that the unwinding film on the apparatus I00 is observed with the assistance of a graduated revolution indicator, errors may readily occur upon disconnection of the apparatus I00 and change over on to apparatus 200.

To overcome these difficulties the present invention provides means for performing the various switching operations automatically. At a predetermined time before the end of the film on apparatus I00 leaves the supply reel an optical or acoustical signal is set in operation by the closing of an electrical contact. This contact is automatically closed when the diameter of the film spool on the reel has decreased to a predetermined size. This contact may consist, for example of a resilient push button. The signal notifies the operator to start the apparatus 200 and to adjust the same correctly according to phase. At the moment when the last winding of film leaves the hub of the supply reel the apparatus I00 is disconnected automatically, and by means of the same actuating element the apparatus 200 is changed over on to the transmission amplifier. In this manner all difficulties are avoided when changing over from apparatus I00 to apparatus 200.

The invention is illustrated diagrammatically by way of example in the accompanying drawing.

The two transmission apparatuses I00 and 200 are operated through the medium of the synchronous motors IN and 20| by the same current supply 3. The two apparatuses are adapted to be connected selectively by means of the relay 40 with the transmission amplifier 5, with which there is coupled the aerial 6 in the known manner.

The actuating relay 40 comprises the contact lever 4|, pivoted at 42, and resting against either one of the contacts I02 and 202 pertaining to the transmitters I00 and 200 respectively.

The actuation of the contact lever 4| takes place electro-magnetically with the assistance of the solenoid 43, which when energized attracts the iron core 44 connected with the lever 4|. When on the other hand the current through the solenoid is interrupted, the lever 4| and the iron core 44 connected therewith is withd awn i qm the solenoid 43 by the spring 45. When, therefore, the solenoid 43 is energized the transmission apparatus 200 will be connected with the transmission amplifier, and when no current passes through the solenoid 43 the apparatus I00 will be connected with the amplifier. As already indicated, the relay is actuated by means co-operating with the film spool in the transmission apparatus. In the drawing these actuating means are shown in the form of contacts I03 and 203, which are controlled by the film spool on the reel I04 and 204 respectively.

The contact 203 is closed as long as there is a film wound upon the reel 204. The contact 203 opens, however, automatically in the moment the last end of the film leaves the reel 204. The contact I03, however, is open when the reel I04 has wound thereon a film and this contact closes automatically in the instance when the last end of the film leaves the reel I04. The solenoid 43 is provided with two windings 5| and- 52 and contains a contact 50 which is opened and closed simultaneously with the contact 202. The operation of the relay 40 is as follows:

It be assumed that the apparatus I00 is in operation and the film unwinds from the reel I04 while a new film is ready for use on the reel 204 of the apparatus 200. Under this condition the contact I03 is open and the contact lev'er 4| due to the action of the spring 45 is pulled to- Ward the right hand side in engagement with the contact I02, so that the circuit of the contact 203 is open, even though the contact 203 itself is closed. As soon as the last end of the film leaves the reel I 04 the contact I03 is automati- 1 previously has been set in operation by the operator, is connected with the transmission amplifier 5, while owing to the opening of the contact I02 the apparatus I00, of course, is disconnected from the amplifier 5.

During the operation of the apparatus 200 a new film can be conveniently loaded into the apparatus I00, whereby the contact I03, of course,

is again opened, but this does not in any way in-- terfere with the operation of the apparatus 200. When the last end of the film in the apparatus 200 leaves the reel 204 the contact 203 is opened and since the contact I03 is already open both windings of the solenoid 43 are de-energized and the spring 45 draws the armature 44 toward the right hand side in which the contact lever 4| engages the contact I02, thereby again connecting the apparatus I00 with the amplifier 5. In this way the-apparatus I00 and 200 are alternately. connected automatically with the transmission amplifier 5, it is only necessary to replace in the apparatus which has been disconnected from the amplifier 5 the empty reel by a reel on which a new film has been wound; This can easily be done while the other apparatus is in operation.

The control receivers for adjusting the correct phase of the transmission system consist of the receivers I I0 and 2 I0, which control in the known and H2 which, for maintaining the synchronous run, are preferably rotated by the same motor I i3 there is produced in the known fashion 'an image, which may be observed by the operator either at the point H4 or at the point 2". The

regulation of the correct phase position is performed by the known means, for example by varying the position of the stator, of the operating motors |I0l or 2M.

What I claim as new and desire to secure by Letters Patent is 1. In a television method, employing a motion picture film, the steps of successively subjecting a plurality of motion picture films to a scanning operation while the films are in motion, starting each succeeding film while the preceding film is still in motion so that both films then move simultaneously, transmitting the images, on the films by electrical currents representative of said scanning, synchronizing the movement of the two films during this period of simultaneous motion, adjusting during the same period the phase position of the image of the succeeding film to be in the same phase as the image of the preceding film, and discontinuing transmission of the preceding film and simultaneously taking up transmission of the succeeding film, as soon as synchronism and phase equalization has been established.

2. The method of televising an animated scene comprising the steps of successively and continuously producing a plurality of moving picture films from said animated scene, immediately subjecting each film successively while in motion to a scanning operation, and' transmitting the images on the films by electrical currents representative of said scanning, starting each succeeding film while the preceding film is still in motion so that both films then move simultaneously,

synchronizing the movement of the two films during this period of simultaneous motion, adjusting during the same period the phase position of the image of the succeeding film to be in the same phase as the image of the preceding film,

- and discontinuing transmission of the preceding film and simultaneously taking up transmission of the succeeding film as soon as synchronism.

and phase equalization has been established.

3. In a television system in which motion pic-' ture films are used as successive intermediate transmission members, including a plurality of transmitting apparatuses each being adapted to subject a motion picture film while in motion to a scanning operation, each transmitting apparatus being adaptedto transmit the images on the film by electrical currents representative of said scanning, a single transmission amplifier adapted to be alternately connected with said transmission apparatuses, means controlled by the motion picture film in each of said transmission apparatuses for automatically connecting the transmission amplifier with the next transmission apparatus when a predetermined length of the film in the transmission apparatus connected with the amplifier has been transmitted, and control receivers, one being connected with each transmission apparatus for synchronizing the movement of successive films during a period of simultaneous motion of two films during the operation of two successive transmitting apparatuses incident to starting the succeeding film while the preceding film is still in motion, said control receivers being adapted to adjust during this period the phase position of the succeeding film to be in the same phase as the image of the preceding film. v

4. In a television system in which motion picture films are used as successive intermediate transmission members, including two transmit ting apparatuses each being adapted to subject a motion picture film while-in motion to a'scanning operation, each transmitting apparatus being adapted to transmit the images on the film by electrical currents representative of said scanning, a single transmission amplifier adapted to be alternately connected with said transmis-. sion apparatuses, means controlled by the motion picture film in each of said transmission apparatuses for automatically connecting the transmission amplifier with the other transmission apparatus when a predetermined length of the film in the transmission apparatus connected with the amplifier has been transmitted, and control receivers, one being connected with each transmission apparatus, a scanning disc for each control receiver, a single drive shaft on which both of said scanning discs are fixedly mounted 'for simultaneous rotation, said control receivers being provided for synchronizing the movement of successive films during a period of simultaneous motion of two films during the operation of said transmitting apparatuses incident to starting the succeeding film while the preceding film is still in motion, said control receivers being adapted to adjust during this period the phase position of the succeeding film to be in the same phase as the image of the preceding film.

5. In a television method employing a motion picture film, the steps of successively subjecting a plurality of motion picture films to a scanning operation, starting each succeeding film while the preceding film is still in motion, so that both films then move simultaneously, transmitting the images on the films by electrical currents representative of said scanning, synchronizing the movement of the two films during this period of simultaneous motion, adjusting during the same period the phase position of the image of the succeeding film to be in the same phase as the image of the preceding film, and discontinuing transmission of the preceding film and beginning transmission of the succeeding film at a predetermined distance from the end of said preceding film.

6. The method of televising an animated scene comprising the steps of successively and continuously producing aplurality of motion picture films from said animated scene, immediately subjecting each film successively while in motion 'to a scanning operation, and transmitting the images on the films by electrical currents representative of said scanning, starting each succeeding film while the preceding film is still in motion so that both films then move simultaneously, synchronizing the movement of the two films during the period of simultaneous motion, adjusting during the same period the phase posi tion of the image of the succeeding films to be in the same phase as the image of the preceding film, and discontinuing transmission of the preceding film before reaching the end thereof and simultaneously taking up transmission of the succeeding film.

GEORG SCHUBERT.'

Images