US2248548A - Television transmitter - Google Patents

Television transmitter Download PDF

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Publication number
US2248548A
US2248548A US34390A US3439035A US2248548A US 2248548 A US2248548 A US 2248548A US 34390 A US34390 A US 34390A US 3439035 A US3439035 A US 3439035A US 2248548 A US2248548 A US 2248548A
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US
United States
Prior art keywords
light
image
disc
film
intensity
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US34390A
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English (en)
Inventor
Schlesinger Kurt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
LOEWE RADIO Inc
Original Assignee
LOEWE RADIO Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by LOEWE RADIO Inc filed Critical LOEWE RADIO Inc
Application granted granted Critical
Publication of US2248548A publication Critical patent/US2248548A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals
    • H04N5/067—Arrangements or circuits at the transmitter end
    • H04N5/073—Arrangements or circuits at the transmitter end for mutually locking plural sources of synchronising signals, e.g. studios or relay stations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
    • H04N3/36—Scanning of motion picture films, e.g. for telecine
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/04—Synchronising
    • H04N5/06—Generation of synchronising signals

Definitions

  • the subject matter of the invention is a television transmission or a method of scanning an original image, whereby the simultaneous transmission of image signals and synchronisation signals takes place in particularly simple fashion and of small cost with the use of one and the same main amplifier.
  • An object of the invention is an arrangement for producing synchronization impulses of constant peak potential.
  • Another object of the invention is an arrangement for producing said synchronization impulses by the scanning holes of the Nipkow disc.
  • Figure 1 shows diagrammatically an embodiment of a television film transmitter.
  • Figure 2 shows the course of the image potentials and synchronization potentials in the transmitter.
  • Figure 3 there is illustrated a disc for scanning an image to be transmitted.
  • Figure 4 shows the size of the image projected on to the scanning disc in comparison with the spacing between the scanning holes.
  • Figure 5 shows embodiments of a television film transmitter according to the invention and Figures 6 and 7 show further forms of embodiments of the present invention.
  • arc lamp I is used to intensely illuminate a film 3 by the use of a condenser or hollow reflectorl, and the film image is reproduced on to to the Nipkow disc 5 by means of one or two lenses 4 and 4'.
  • a photo-cell 6 with connected image amplifier l is placed behind the Nipkow disc, preferably with the interposition of a collecting lens 8, there is available at the output of the image current amplifier 1 the signalling potentials which correspond to the light intensity values of the original film 3. No synchronisation impulses are present at the output of amplifier I.
  • the transmission is assumed to be a so-called positive transmission with black synchronisation signals.
  • a transmission of this kind is illustrated diagrammatically in Fig. 2.
  • the time t has been entered as abscissa and the aerial current i of the transmitter as ordinate.
  • the light intensity signals increase the aerial current in the case of white and reduce it in the case of black, but even with extreme black the aerial current should not become zero.
  • the entire current intensity interval between'a very white 1.
  • Nipkow disc of the transmitter 5' in Fig. l.
  • a Nipkow disc of this kind is as follows:
  • the new method is illustrated in Fig. 5.
  • the film optical system remains the same as in Fig. 1, and comprises the arc lamp l with the reflector 2, the film 3, which is intended to run continuously, and preferably two lenses'4 and 4'.
  • the film is assumed to be one of such brilliance that the light impinging on the Nipkow disc 5 com pletely disappears at the black points, and is transmitted at the white points practically without weakening.
  • the idea according to the invention consists in projecting 'an additional uniform lighting over the field of the filmimage on the disc 5 by a special auxiliary light source 23. Whilst the film reproduction 24 as shown in Fig.
  • this additional lighting i projected over a width which is exactly the same in size as the width of the film image reproduction 24, i. e., auxiliary light and film light are caused exactly to register.
  • the arouate portion of the disc for this lighting is,1however, shortened by an interval 25 amountingto approximately 10% of the spacing between two adjacent scanning apertures M. It will bequite obvious what occurs now in the photo-cell circuit B.
  • the invention which has been described in the above in conjunction with a perforated disc transmitter, may also be employed, however, quite generally. For example, it is quite readily possible to make use of the same in transmitters where the subject matter transmitted originates in a studio rather than being derived from a film.
  • FIG. 6 An arrangement for carrying-out the invention in practice in the case of a cinema transmitter is illustrated by way of example in Fig. 6, said arrangement containing in addition to the features set forth in the above a particularly advantageous arrangement. for producing the auxiliary lighting.
  • I is the arc lamp, this .beingthe only source of light occurring in the system.
  • the reflector 2 or condenser the light is concentrated on to the film, the image to be transmitted on each occasion being represented by the section 3a. It'is assumed that the light intensity of the image field is uniform over the entire picture area 311, as may be expected in the kinematographic art.
  • the transmitter according to the invention is intended to operate with a circular concentrically apertured disc- 5, which accordingly has the property of scanning merely one single line in the entire height of the image 3a;
  • the image-3a is reproduced sharply on the disc 5 by means of two lenses 4 and 4.
  • the line 32 scanned by the disc 5 represents the only line in the entire image which is utilised optically, and all remaining lines of the film are not embraced by the scanning operation. Accordingly the total remaining light on the picture area 3a is useless for the television transmission.
  • a very considerable additional amount of light must be projected on to'the film. reproduction 24 on the Nipkow disc, and this additional lighting must be approximately equal in amount to the lighting intensity of snowy white points in the original.
  • the scanned line 32 is not, as hitherto usual, disposed at the centre of the image, but the line of the original reproduced on the scanning disc is displaced in relation to the path of the bundle of rays 33 and located at 32.
  • a deflecting prism 34 preferably one composed of durable glass (Ignal glass) projects that portion of the light which otherwise would impinge on the picture area 3a above the line 32 to be transmitted vertically to the path of the reproducing rays.
  • One or two lenses 31 and 38 are provided, and then in turn two deflecting prisms 39 and 40.
  • the last-mentioned prism is tilted to a somewhat greater extent, so that the auxiliary light, as required, covers the same area of the scanning disc 5 as the reproduction of the original picture area 3a.
  • the intensity of the auxiliary light may be adjusted in very simple fashion by an iris shutter provided for example at 4
  • auxiliary lighting may be employed in simple fashion for automatically regulating the degree of amplification according to the lighting intensity.
  • a part of the by-passed light is directed upon a white plate 43 positioned near and inclined with respect to the slot 35, and is reflected against a control photo-cell 44.
  • this regulating potential may be conducted in the form of a bias to the control grid of the tube 41 by way of the line 48 in order to attain the desired effect and the maximum output potential is maintained constant independently of the lighting intensity, the sensitivity of the amplifier being increased upon a decrease in the illumination by the are I, and vice versa.
  • the amplification is so adjusted that (1) Only upon scanning such points of the original which are as clear as'glass on the one hand, and points completely without light on the other hand, at which the auxiliary lighting disappears, i. e., in the dead angle of the image, are the limits of the modulation characteristic of the transmitter reached.
  • the aerial feed current is adjusted to that particular stationary value, which upon passage hrough a black-and-white scale in the original corresponds with the grey value of this scale.
  • This aerial feed current is relatively high and amounts to approximately 60% of the maximum aerial current.
  • FIG. '7 Another optical system for carrying out the method is shown in Fig. '7.
  • This arrangement has the advantage that the same lenses which are employed for reproducing the film also perform simultaneously re-reproduction of the light ing slot.
  • a light source l with a condenser reflector 2, and by means of a prism 34 a large part of the light, which does not fall on to the scanned line 32, is deflected out of the main ray.
  • the by-passed light and the primary light are united before reaching the first lens 4.
  • a television transmission arrangement comprising a Nipkow disc containing a row of scanning holes, a photoelectric cell, a single source of light, means including said source of light for projecting an image of the object to be transmitted onto said Nipkow disc, and means including said source of light for projecting an additional light bundle upon the image projection onto said Nipkow disc, said additional lighting exactly covering the image field, the length of said image field being smaller than the spacing between said scanning holes, and means for producing an image current in said photoelectric cell by scanning said image field, an electronic amplifier for amplifying said image currents, a light responsive element, said light responsive element being positioned to receive light from the single source in proportion to the intensity of the source to produce a voltage proportional to the light intensity, and means to control the effectiveness of the electronic amplifier by the produced voltage whereby the strength of the amplified image currents will be substantially unailected by changes in the intensity of the source of light.
  • a television transmission arrangement comprising a Nipkow disc containing a row of scanning holes, a photoelectric cell, a single source of light, means including said source of light for projecting an image of the object to be transmitted onto said Nipkow disc, and means including said source of light for projecting an additional light bundle upon the image projection onto said Nipkow disc, said additional lighting exactly covering the image field, the length of said image field being smaller than the spacing between said scanning holes, and means for producing an image current in said photoelectric cell by scanning said image field, an electronic amplifier for amplifying said image currents, means responsive to the light from the source for producing a potential substantially proportional to the intensity of the single source of light, and means for controlling the image current amplifier by the produced potential whereby the strength of the amplified image current will be substantially unaffected by changes in the intensity of the single light source.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Facsimiles In General (AREA)
  • Details Of Television Scanning (AREA)
  • Projection Apparatus (AREA)
US34390A 1934-08-04 1935-08-02 Television transmitter Expired - Lifetime US2248548A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE460709X 1912-07-28
DE2226997X 1934-10-11

Publications (1)

Publication Number Publication Date
US2248548A true US2248548A (en) 1941-07-08

Family

ID=32070593

Family Applications (2)

Application Number Title Priority Date Filing Date
US34390A Expired - Lifetime US2248548A (en) 1934-08-04 1935-08-02 Television transmitter
US44063A Expired - Lifetime US2226997A (en) 1934-08-04 1935-10-08 Television transmitter

Family Applications After (1)

Application Number Title Priority Date Filing Date
US44063A Expired - Lifetime US2226997A (en) 1934-08-04 1935-10-08 Television transmitter

Country Status (5)

Country Link
US (2) US2248548A (US06262066-20010717-C00315.png)
BE (2) BE410499A (US06262066-20010717-C00315.png)
FR (2) FR793449A (US06262066-20010717-C00315.png)
GB (2) GB460709A (US06262066-20010717-C00315.png)
NL (1) NL51102C (US06262066-20010717-C00315.png)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429331A (en) * 1943-12-08 1947-10-21 Rca Corp Photoelectric apparatus for inspection of paper strips

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3049590A (en) * 1959-07-17 1962-08-14 Brian E Hooper Negative enlarger using closed loop television

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2429331A (en) * 1943-12-08 1947-10-21 Rca Corp Photoelectric apparatus for inspection of paper strips

Also Published As

Publication number Publication date
FR793449A (fr) 1936-01-24
GB464049A (en) 1937-04-07
US2226997A (en) 1940-12-31
FR46642E (fr) 1936-07-11
GB460709A (en) 1937-02-01
BE410499A (US06262066-20010717-C00315.png) 1935-08-31
BE411671A (US06262066-20010717-C00315.png)
NL51102C (US06262066-20010717-C00315.png) 1941-10-15

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