US2227414A - Television transmission device - Google Patents

Description

Dec. 31, 1940.

HANN S-HEINZ WOLFF TELEVISION TRANSMISSION DEVICE Filed July 16, 1938 2 Sheets-Sheet l jnveniur: LWLW 4 Dec. 31, 1940. HANN$.HE|Nz WQLFF 2,227,414

TELEVISI ON TRANSMISSION DEVICE Filed July 16, 1938 2 Sheets-Sheet 2 Patented Dec. 31, 1940 TELEVISION TRANSMISSION DEVICE Hanns-Heinz Wolfi, Berlin, Germany, assiznor, by mesne assignments, to Loewe Radlo,lnc'., a corporation of New York Application July 16, 1938, Serial No. 219,607 In Germany July 19, 1937 4 Claims.

In television transmissions in which the scanning of the picture takes place by'means of an iconoscope or the like there result at the receiver distortions of the picture which, in the case s of picture of high definition, may assume unacceptable proportions. These distortions are based on the chronological delay of the synchronization impulses in relation to the image signals which result by way of the modulating lo stage of the transmitter and the demodulation stage of the receiver.

The Figs. 1-3 are intended to explain the operation of an arrangement of this kind. There is: i

i the iconoscope of the transmitter,

tr the synchronizing impulse generator for the line deflection on the transmitter,

fly the synchronizing impulse generator for the 20 frame deflection,

Zinc the relaxation oscillation generator for the line deflection,

t the relaxation oscillation generator for the frame deflection,

25 t the amplifier of the transmitter,

in Fig. i the iconoscope I possesses a pair of deflecting plates each iorithe horizontal'and the 40 vertical deflection. The deflecting potentials are generated in the relaxation oscillation gem craters 3a: and 3y, which are controlled by the impulse generators 2m and 2y. In the amplifier t there are amplified the synchronization im-' pulses of the generators 2a: and 231 and the image transmimion; and in the modulator 5 following thereon the carrier wave of the transmitter is modulated by this image potential mixture and passed to the transmitter 6. At the receiver the so synchronization impulses are filtered out by a separating device and employed for controlling the relaxation generators Ma: and My for th deflecting potential of the Braun tube.

The instants of the image signals caused by 55 thescanning in an iconoscope of the transmitter (Clf17M9-5) are dependent on the deflecting oscillations controlled by the synchronizing impulses. The instants of the image signals reproducing the image at the screen or the cathode ray tube of the receiver are dependent on the image signals given 5 from the transmitter. The deflecting oscillations for deflecting the cathode ray at the receiver is also controlled by the impulse given from the impulse generator or the transmitter. These synchronizing siwais are longer delayed W on the way between the impulse yenerator oi the transmitter and the deflecting oscillator oi the receiver, than the image signals on the way bechronizing impulses pass more "elements than the image signals, and since the passed elements delay the synchronizing impulses longer than the image signals. Therefore, at the receiverthe positions of the image signals on the room to duced image are displaced in view of the positions of the image signals on the transmitted picture. v

The subject matter of the invention is an arrangement for tutating the distortions oi the to picture at the receiver. This takes place by the tact that the impulses which for controlling the relaxation generators tr, to for the iconoscope i at the transmitter end experience the same de lay as the pulses ior controilinz the relaxa- W tion generators list, My tor the cathode ray tube it at the receiver...

The arrangement semi-ding to the invention is explained lay Fla. 2. The synchronization impulses of the generators to and i are conducted 35 only in the known iashion with the image signals to the transmitter for controlling the receiver. The connection hetween the impulse generators tar, ty and the relaxation oscillation v generators to, to as shown in liig. l is omitted. 40 At the aerial coil of the transmitter 5 there is provided a receiving device l, which receives the television transmissions. The synchronization impulses are filtered out by a separating device it in the known manner from the mixture ret5 ceived and employed for controlling the relaxation generators tax, is for the iconoscooe it. The delays in the synchronization impulses hetween the impulse generator of the transmitter and the relaxation generator of the receiver acto cordingly exactly correspond to the delays in. the impulses from the impulse generator to the relaxation generator' for, the iconoscope. In

this way it is accomplished that differences in time between the deflecting potentials and the 5B image potentials at the cathode ray tube of the receiver are eliminated. The arrangement can also be employed if records are to be made by an iconoscope at a comparatively large distance away from the transmitter. In this case the control of the relaxation potential generators of the iconoscope also takes place by the impulse generatorsof the transmitter by way of a special receiving device.

Fig. 3 shows a possibility of use of this kind. A television transmission is to be recorded by means of the iconoscope l at a comparatively long distance away from the transmitter, for example on a playing field. The impulse generators 2a: and 21/ are located at the television transmitter. The synchronization impulses are transmitted in wireless fashion to the portable recording apparatus, where they are employed for controlling the relaxation oscillation generators 3m, 33 located there. In this way it is possible to make the portable recording apparatus more simple in design and to ensure the synchronization of the receiver by the transmitter. Th record to be transmitted can be conveyed from the recording apparatus to the transmitter by a wire connection or special cable. It is also possible, and particularly convenient, to perform the transmission in wireless fashion by the use of an auxiliary transmitter. In this connection there canbe employed for the auxiliary transmitter a desired frequency or the same frequency as that ,of the main transmitter or half the frequency or another sub-harmonic frequency of the main transmitter. If there is employed for the auxiliary transmitter the same frequency as for the main transmitter, the main transmitter acts as amplifier. In this case modulating stages and demodulating stages in the main transmitter can be dispensed with. When using one-half of the frequency or any other sub-harmonic frequency of the main transmitter a frequency doubling or multiplication requires to be performed at the main transmitter. of the method previously mentionedthe advantage that reactionary effects of the main transmitter on the auxiliary transmitter are avoided. In'Fig. 3 there is shown a wire connection for transmitting the contents of the picture to the transmitter.

I claim:

1. In a television transmitter a cathode ray tube for scanning the picture, deflecting oscillators for deflecting the cathode ray of said cathode ray tube in the vertical direction and in the horizontal direction, generators generating impulses controlling said deflecting oscillators and synchronizing the deflecting oscillators of the receiver, delaying means consisting of a special device receiving the synchronizing impulses transmitted by the transmitter and being coupledvia a demodulator, arr amplifier amplifying said impulses and a separating device separating the line and frame synchronizing impulses from the image signals and each from one another to the tube,

This method possesses in face.

deflecting oscillators of said scanning cathode ray-tube.

2. In a television transmitter a cathode ray tube for scanning the picture, deflecting oscillators for deflecting the cathode ray of said cathode ray tube in the vertical direction and in the horizontal direction, generators generating impulses controlling s lid deflecting oscillators and synchronizing the deflecting oscillators of the receiver, delaying means consisting of a special device receiving the synchronizing impulses transmitted by the transmitter and being coupled via a demodulator, an implifler amplifying said impulses and a separating device separating the line and frame synchronizing impulses from the image signals and each from one another to the deflecting oscillators of said scanning cathode ray said special receiving device and said scanning cathode ray tube being placed in a comparatively long distance from the other parts of the transmitter.

3. In a television transmitter an iconoscope for scanning the picture, deflecting oscillators for deflecting the cathode ray of said cathode ray tube in the vertical direction and in the horizontal direction, generators generating impulses controlling said deflecting oscillators and synchronizing the deflecting oscillators oi the receiver, delaying means consisting of a special device receiving the synchronizing impulses transmitted by the transmitter and being coupled via a demodulator, an amplifier amplifying said impulses and a separating device separating the line and frame synchronizing impulses from the image signals and each from one another to the deflecting oscillators of said scanning cathode ray tube, said special receiving device and said iconoscope being placed in a comparatively long distance from the other parts of the transmitter, only the scanning electrode of the iconoscope being connected by cable to the modulator of the transmitter.

4. In a television transmitter an iconoscope for scanning the picture, deflecting oscillators for deflecting the cathode ray of said cathode ray tube in the vertical direction and in the horizontal direction, generators generating impulses controlling said deflecting oscillators and synchronizing the deflecting oscillators of the receiver, delaying means consisting of a special device receiving the synchronizing impulses transmitted by the transmitter and being coupled via a demodulator, an implifler amplifying said impulses and a separating device separating line and frame synchronizing impulses from the image signals and each from one another to the deflecting oscillators of said scanning cathode ray tube, said special receiving device and said iconoscope being placed in a comparatively long distance from the other parts of the transmitter, only the scanning electrode of the iconoscope being connected by cable to the modulator of the transmitter, said special receiving and said iconoscope being mounted in a transportable television scanning apparatus.

HANNS-HEINZ WOLFF.

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