DE1023079B - Color television system - Google Patents

Description

GERMAN

Color television system

Applicant:

NV Philips' Gloeilampenfabrieken,
Eindhoven (Netherlands)

Representative: Dipl.-Ing. K. Lengner, patent attorney,
Hamburg 1, Mönckebergstr. 7th

Claimed priority:
France October 2, 1953

Jean Perilhou, Reine, Seine (France),
has been named as the inventor

The invention relates to a color television system with three basic colors and with color change in line sequence and preferably with single interlaced scanning, in which a complete scanning cycle several Includes pairs of vertical scans (raster scans).

Such a system enables the reception of color television pictures by means, the simplicity of which is almost comparable to that of the means used in the technique of Black and white television are used; perfect compatibility is also achieved, and thus the existing black and white receivers can reproduce the color transmissions without difficulty.

The various signals necessary for reproducing the images in the color television receivers can thereby be transmitted without an expansion of the frequency band is required. As is well known, the Reduction (or at least the non-widening) of the frequency band to an outstanding degree the future Development of television, both

for transferring black and white images such as from

Color images. η

In known systems of this type, the individual

The color television receivers can change colors within a grid and for a full 25 transferred to the same extent, d. H. in particular, that be moderately easy.

during every raster all colors appear and that to

every complete color scan of an image the same wise green, always present and writes one of two Heard number of green, blue and red lines. Lines on the receiver screen. The other lines In practice, however, most of the images behave in a manner that behaves like an obscurity in successive rasters contain more green than red or blue; which are written alternately in red and blue. Signals for the latter colors are therefore used in the interlaced process to which the invention is based

Medium transmitted with a lower amplitude than the rest is not necessarily limited, is then in Green signals, indicating poor utilization of the over-four scans in each line of a field (raster) bearing arrangement results. Next is the green grain - all colors, i. H. for example green - blue - green - component the one that is largely composed of the luminosity red, written. Since two fields are used for each picture listening to the same, transmitted as a black and white image, a full color image is obtained after eight Scene corresponds. The rendering of a color image with grids.

A black-and-white receiver is consequently all the more The limitation, or at least the non-extension

The better or more frequently the green component of the image modulation frequency band is made possible by this-color image is transmitted. light that a given total number of horizontal lines

is scanned per second and such a number of complete color images per second (raster) is selected, that's enough to avoid flickering. Preferably a number of horizontal single color lines written equal to the number of lines on black and white television. In order to form a full color image to write the same line at least once in a row in each of the colors and in order to

It has also been found that the switching means in the receivers are particularly simple when not all three colors need to be transmitted during a vertical scan (raster).

In a circuit arrangement of the type mentioned at the outset, this is achieved when, according to the invention, during a vertical scan only two colors are transmitted alternately, one of the colors, preferably

Green occurs in all vertical scans, while the ability to maintain a certain norm can be

the other two colors appear alternately from one vertical scan to the other. Because according to the invention during a vertical scan (raster) only two colors are transmitted, which are reflected on the lines.

in the system according to the invention by choosing the vertical scans (whose frequency is actually increased) and, on the other hand, by choosing the repetition frequency one color on the same line and finally through that

709 850/158

Frequency of the full color images (which is actually reduced) can be achieved that the for the mentioned The frequency band provided for in the standard is not expanded or even reduced.

The top of the vertical scanning frequency is limited by the condition of compatibility, i.e. h., she may never higher than the highest frequency to which the deflection generator of the vertical scan should be selected an existing black and white receiver can be set. With the current state of Technique, the latter frequency can generally be almost doubled, which increase is largely used the invention is sufficient.

The change of the color lines can be carried out in various ways within the scope of the invention. A specific example is given in the table below. It is assumed that the first Vertical scanning z. B. hits the odd lines and that the lines are written alternately in red and green will:

2 3 4th 5 6th 7th 8th 9 10 11 12th 13th series 1 2 vertical scanning (raster) 4th 5 6th 7th S. series
the horizontal
Scan lines Red 3 Red green 1 green green blue green etc. green green Red blue Red green blue Red Red green green green blue green green green Red blue Red green blue Red Red green green green blue green green green Red blue Red green blue Red Red green green

Since in the following grid, z. B. 2, compared to the previous grid, z. B. 1, the green lines only a little are shifted and in particular are not in the middle of the first green lines written, the result is a Apparent upward movement of the green image, which is, however, very disturbing. This apparent movement can according to a further development of the invention by a periodic reversal of the meaning of this movement, preferably by switching the color sequence (color swap). One of the Colors are skipped, which amounts to the fact that a color change by two successive ones Color change is replaced.

The change of colors within the successive Lines can be made by means of an electronic switch, with the electrical setting is reversed every time a line sync pulse is received. The engagement of the second Color can be done in a similar manner, e.g. B. a frame sync pulse occurs.

The mentioned reversal of the order for elimination the apparent wandering of the green image can be achieved by a similar switching arrangement, additional sync pulses should also be transmitted in order to ensure the correct assignment of the signals to the Ensure playback facility. These additional pulses can be added to the beginning or end of the Image, d. H. are introduced into those lines which remain invisible on the display screen and therefore may be changed without disadvantages.

The further description on the basis of the figures, which are only given as non-restrictive examples, is the Realization of the invention clearly understandable, every feature of the text and the figures being self-evident forms part of the invention.

The figures show schematically the organs that the known devices for z. B. Black and white television (monochromatic television) should be assigned.

Fig. 1 relates to a transmitter;

Fig. 2 relates to a receiver with a three-color tube with three electron beam systems for generating the colored image;

Fig. 3 relates to a receiver with a three-color tube with a single electron beam system but with color control grids;

Finally, FIG. 4 relates to a receiver with two separate tubes, whose respective images are transmitted through a suitable optical device or superimposed on one another by projection.

The mode of action of the usual single-color transmitters and receivers as well as their organs, which are known per se and need not be described or illustrated; however, they are indicated in a block diagram in the figures if this makes the explanation easier.

According to FIG. 1, the scene or the image to be transmitted is analyzed by means of a camera 1 which is known per se. This camera 1 contains z. B. on the one hand a first pick-up tube 2 of any type, e.g. B. an iconoscope or an orthicon, which supplies the electrical signals that correspond to the green image component, and on the other hand a second similar pickup tube 4, which supplies those electrical signals that correspond to the red or the blue image component, depending on the incident light through a red filter 5 or a blue filter 6 falls through. These filters 5 and 6 are carried by a rotating disk 7, which is moved by means of a synchronous motor 8, which is fed by an arrangement Qa and synchronized in a known manner with respect to the vertical pulses generated in the generator 14.

5 6

nism is maintained and regulated in the phase. The catcher 17 is fed, the correct assignment The vertical deflection device 9 for the tubes 2 and 4 will also provide signals to the beam systems 22 and 23 synchronized with respect to the vertical pulses; that achieves. This creates color images that immediately appear For the sake of clarity, the line deflection device is not visible on the screen of the tube 18, shown. 5 Fig. 3 shows a receiver with a three-color die coming from the tube 4 and from the tube 2 cathode ray tube 26 with a single electron-electric tube Signals become after they preamplifier 10 beam system of color control grid type; it contains about or 3 have passed, a switchover arrangement 11 to the same essential organs as the recipient out, which is actuated in the cycle of the line sync pulses Fig. 2.

is and the z. B. an electronic flip-flop circuit which contains the three components green, red and blue. This means that either the green or the red speaking signals are or blue signals fed to the transmitter 12, which also turns all.

conventional organs, in particular the generators 13 and 14. The video signals are fed to the beam system of the tube of the line or raster synchronization signals with the 26. For selection, the color control frequency fz or fr and the required modulation grid 29 of the tube 26 voltages Ug ₁ Ur or Us are included . In addition, a generator 16 is provided, which remains of the understanding, but whose value is controlled for the scanning of a table deflection generator 14 and color control green, red or blue line is different. This provides synchronous signals that match the phases, the electron beam receives an additional deflection immediately before returning between the light filters 5 and 6 and the surrounding screen and hits the switch 11 of the transmitter and the associated switching fluorescent substance of the corresponding color on the screen. Make sure in the tern of the recipient; this color control device 25a takes place, for example, the line-frequency reversing signals exist z. B. from a pulse train with circuit (f _z ) between the required for green after the line frequency, for example five to six times deflection voltage Ug and the output of the device 25, higher frequency. These color change synchronous pulses 25, which have a raster frequency f _r for blue or red, can easily be separated by means of suitable filters. such post-deflection voltage Ub or Ub supplies.

A generator 15 can also be assigned to the transmitter 12. These switchovers are carried out by the device 28

be that of the line and the vertical deflection depending on the line and screen frequency

generator 13 and 14 is controlled and which does the above, with the correct phase assignment in

mentioned color swapping sync signals with a dependence on the color control sync pulses.

Frequency f _w supplies, the z. B. is made from additional pulses.

In the middle of a line at the end or beginning of the image, according to FIG. 4, the video from the receiver part 17 can stand and a periodic reversal of the signal via a switching device 19 of a first apparent shift of the lines in the image plane tube 30 for writing the green lines and one effect. The color swapping sync signals can be fed to the changeover switch 11 to the second tube 31 for writing the red or blue lines and fed to the lines.

Swap the rhythm of the colors so that periodically the switching device 19 separates in the cycle of the

a reversal of the above-mentioned apparent creeping line frequency f _z the green and the blue or red

movement occurs. Video signals. The one with half a raster frequency - surrounding

Fig. 2 shows a receiver with a three-color 40 ° 2

Cathode ray tube 18, the three beam systems 21, 22 fende motor 13 rotates the disc 32 with a red and and 23 contains. From the actual receiving part 17 a blue light filter and thereby causes the re-transmission of the video signal to a first switching device 19 would give the red lines during the one vertical, which is actuated at the rate of the line frequency f _z scanning and the blue lines during the next and the green lines Image lines corresponding to 45 vertical scanning. By means of the synchronizing device video signals to the beam system 21 and the blue 39, to which the line, raster and color control synchronous or red image lines corresponding video signals of an impulse are fed, the switching device 19 and the motor are operated at the raster frequency f _v 33 actuated, whereby the fixed direction 19 a supplies, which ensures the assignment to the beam color assignment. The two tubes 30 systems 22 and 23 for blue and red causes. 5 ° and 31 thus generate two incomplete, separate partial

The first switching device 19 includes, for. B. a picture, ζ. B. a green and red field during the flip-flop, which is controlled by the line pulses, first vertical scan (e.g. only the odd lines and the supplied video signal periodically to one or the final picture), then a green and blue part of the other output passes. Correct assignment to the image during the second vertical scan (e.g. only the transmission of the green or blue or red 55 straight lines of the final image) etc. of suitable color control sync signals with the stores, e.g. B. by projection on a single screen. Frequency f _s from the receiver 17 is controlled. One of the particular advantages of this type of receiver are e.g. B. the raster sync pulses according to the invention is that there are only two interlaced lines, which are different images in successive rasters instead of three that are optically different phase positions with respect to the line synchronous superimposed. It can be seen that this is what the con-pulses exhibit. structure much simplified.

With the second switching device 19 <z, the It is important to note that the condition of the

red and blue video signals the electron beam compatibility with the existing black and white reception

systems 22 and 23 for red and blue color rendering 65 catchers is always met; because on the one hand the

fed. The switching takes place in the cycle of the frequency of the vertical scans (in this description

^ asterfrequency / γ. The device 19 ″ can also be easily regulated (e.g.

flip-flop included, which is triggered by the raster pulses by means of a simple button) to the correct

is made. By the device 24, which ensures the color reception of color transmissions, and

iteuersynchronsignale the frequency f _s from the receiver 70 on the other hand, these receivers do not contain video signal

toggle switch and no means to separate or individually reproduce the various color components, so that all transmitted video signals contribute to the formation of the black and white images.

After all, it goes without saying that numerous Variants are possible within the scope of the invention. This concerns z. B. the replacement either in the transmitter or in Recipients of any known organ or known Switching by an equally known organ or switching with equivalent effect.

Claims (9)

Claims: 10 1. Color television system with three basic colors and with color change in line sequence and preferably with scanning in single interlace, in which a complete scan cycle several pairs of vertical scans characterized in that only two colors alternate during a vertical scan with one of the colors, preferably green, in all vertical scans occurs while the other two colors alternate from one vertical scan to the other appear. 2. Color television system according to claim 1, characterized in that the number of vertical scans per second compared to the black and white standard is only increased as much as the control option of the Vertical frequency oscillators of the usual black and white receivers are permitted. 3. Color television system according to spoke 1 or 2, characterized in that the change of the color lines by means of a first electronic flip-flop (19) is carried out during each vertical scan, which is controlled by the line sync pulses, while the alternation of colors between two successive vertical scans by means of a second electronic flip-flop (19 a) is carried out, which is controlled by the raster sync pulses. 4. Color television system according to one of the preceding claims, characterized in that a Color control sync signal is transmitted, which preferably consists of a pulse train with an opposite the line frequency, e.g. B. five to six times higher frequency, there is, and that in the receiver means a suitable filter is separated, and that for phase control of the switch (19) with respect to the Position of the color filter (or similar organs) of the transmitter is used. 5. Color television system according to one of the preceding claims, characterized by measures, by which the sense of the apparent creeping movement of the lines is periodically reversed, preferably by switching the color sequence (color swap). 6. Color television system according to claim 5, characterized in that the color swapping by means of the first toggle switch (19) is carried out by an additional, preferably a conventional Synchronous pulse similar pulse is controlled, the z. B. in the middle of an end line or a beginning line, of the image and is only introduced during certain scans. 7. Color television system according to one of the preceding claims, characterized in that in the Receivers the images are generated in two different tubes, one of which is an image in the color occurring during each image scan and the other alternating images of one and the other other color, with the images of the two tubes thereon by any known means, preferably by projection on a screen, are superimposed on each other. 8. Transmitter for a color television system according to one of the preceding claims. 9. Receiver for color television system according to one of the preceding claims. References considered: Proceedings of the IRE, October 1951, p. 1326, right column;
Journal of Applied Physics, 1952, p. 302, Fig. 4. 1 sheet of drawings © 709 850/158 1.58