DE2158218C3 - Method and circuit arrangement for predistortion of a three-line sequential color television signal for a circuit for converting this signal into an FBAS color video signal - Google Patents

Description

its compatibility in terms of black and white using equations (4b and 4c)

Reproduction with the correct gradation of the standardized results for the color difference signals

PAL signal and also a color image "" _ " _c , - ," _r , ,,,

generated, which according to the additional application ^B ~ ^tY = ^f b + Fz - (Fy + Fz) (6)

P 19 43 672.7-31 color saturation still occurring - 5 F _B * - Fy * - F _B - Fy <6a)

avoids mistakes. FnKn h H it

The invention consists in the fact that the trizeilen- ^ nisprecnena well.

sequential color television signal an additional set signal Z, ^Fr * ~~ ^F r * = Fr - Fy (7)

that the color signals R, G, B with such an amplitude It also results in the desired color

contains that the addition of the additional signal io differential signals of the standardized PAL color signal.

contained sequential color signals a luminous The method can correspondingly on a system

density signal Fm results, which are applied equal to the luminance, in which, for example, instead of

signal / of the corresponding black and white television the sequential color series (G, R, B) the sequential

signals is added at least in proportions. Color signals (Y, B, R) "are transmitted.

The invention is based first of all on the exemplary embodiment of a circuit for carrying out the knowledge that the luminance signal Y _{M is} not the further developments of the method according to the invention and its appropriate form using Ym = 0.59 G + 0.2 R + 0.11 B (Y) drawing explained.

It shows

but the form _ao F i g. 1 the tri-line sequential recording in

Ym = 0.33 (G + R + B) (2) principle,

F i g. 2 is a block diagram of a circuit for

who is responsible for the improvement of the image reproduction in the implementation of the procedure,
Area of horizontal edges, according to the main F i g. 3 is a block diagram of an expedient

patent 19 36 594 is required. The simultaneous development of a circuit for implementing the fulfillment of both demands seems to be due to the contradicting procedure,

proverbial statement of equations (1) and (2) F i g. 4 and 5 show a circuit for converting a

not possible. tri-line sequential color television signal into a composite video

A major inventive step is the color video signal.

Understanding that in order to achieve the circuit 30 shown in FIG. 1, on the same track of an effect not produced according to the main application, the recording medium is alternately required line by line, for example in a system with 0 to 0.5 MHz the color signals R, G, B as well as in obtaining the composite color video signal from the range from 0, 5 to 2 MHz in each line a luminous sequential color signal (R, G, B), the original density signal Yh recorded.
To transmit color signals. Rather, they are sequential. 2, the tielle substitute color signals G *, R *, B * are to be used at terminals 31, 32, 33, the color signals R, G, representing the three primary colors, from the original sequential color signals B in the range from 0 to 0.5 MHz fully available, composed and the equation (2) in the With a rotating in direction 43 switch 34 form γ _ 0 33 (G * + R * + B *) '2a) the three color signals R, G, B line by line -

'^;v; 40 tapped each other and an adder 40 trains

fulfill. The proportions contained therein of the originating leads. The switch 34 is controlled by a synchronizing sequential color signals G, R, B , the stage 35, which also meet the identification pulses for equation (1). Identification of the color signals emits. The color

From this it follows for an additional signal Z that all signals are also fed to the evaluation stages 36, sequential color signals 45 37, 38 evenly. The weighted color signals, which should form the additional signal Z for the case of complete matching, are added to the sequential color signal regardless of the position of the rotating switch 34 in the adder 40. After the identification pulses of the synchronizing stage 35 and the luminance signal Yh = 0.5 to 2 MHz, which is available at terminal 30, have been added to the sequential color signal in the adder 50 stage 42, the resulting signal is fed to the recording device 1.
55 Should the exceeding or falling below certain!

. _. . ,. ". ...,. ,,. , Amplitude values of the transmission channel for di (

is obtained with equation (2 a) for the luminance _seque ntiellen color signals to be avoided, is signal to Ausmittlung and demodulation of _it color- _{jn the dargestelhen in p {3} Ausführungsbeispie trägerfrequent transmitted sequential color signals: _{dner circuit according to an} advantageous Ausbilduni Y _M * = 0.33 (G -f R + B + 3 Z) (2b) 60 of the method according to the invention favorable if at

for example by a damping level 39 the ur

For the color difference signals, tri-sequential color signal around the faculty _{applies because of the mainspring}

zation in the corresponding circuit of the patent _{tQr c is weakened} and -lic individual in addition

Application P 19 43 672.7-31 _{signal z ent} h _a ltenden color signal components by ent

Fy * = 0.59 Fa * + 0.3 Fr * + 0.11 F _n * (5) 65 meaningful interpretation of the assessment levels 36 to 3

increased by (1 - C). The made

The equations (4a to 4c) result in a weakening of the discrete color components in tr:

Fy * = Fg + F ₁ I + F _B + Fz - Fy - | - Fz (5a) sequential color signal can be increased by an increase

to the shape (1): With G * = G + - 0.03 R - 0.22 B (3) Z = 0.26 G R * = R + B * = B + Z (4 a) Z (4 b) Z (4c)

of the difference signals in the circuit of FIG. 4 stage 13 fed. The inputs of this stage are equivalent by dashed amplifier elements and are dimensioned in such a way that the adder stage 13 or a slightly changed circuit design can again compensate for the signal according to equations (2a) and (2b) in color subcarrier. Should a deterioration in the frequenter form supplies. Not characterized result is a, the signal to noise ratio of the sequential color signal in 5 low frequencies from 0 to 0.5 MHz containing purchase to be taken, it is also with the aid of luminance signal Fyμ that in a demodulator 14 of a non-linear Diskriminatorscha'tung 41 and demodulated in the adder 4 with the luminous three further adder stages 36α, 37α, 38α possible, density signal} '// to the complete luminance in the manner of a control in the case of an over or under signal and a portion of the single io terminal 15 in one exceeding predetermined amplitude values standing PAL-FBAS-Signal forms. To weaken the color components of the additional signal or to suppress signals R *, G *, B * (in color subcarrier-frequency form) completely. The three inputs of the adder stage 13 generated by the discriminator are interchanged from 41 and the adder stages 36a, 37a and 38a ge line to line. But this has no imagined limiting device is such that it must, because the three inputs are equivalent. The signal level of those 15 contained in the additional signal can be seen that the extraction of the luminance color signal components which are added to the sequential signals Ym without the use of line-frequency color signals with the same sign are reduced.

The modulated color subcarrier for the composite signal

exceeds and / or that the signal level of that is obtained as follows: From the signals

The color signal components contained in the additional signal 20 Fc *, Fr *, Fb * are shown in a matrix 10 by color

are reduced, which the sequential color signal with carrier frequency matrixing color carrier frequency Si

opposite signs are added if gnale F _B * -y * = F _n - _Y and F _R * -y * = F / jr [after

this falls below a predetermined signal level. Equations (6a) and (7a)]. The luminance

With this limiting device, a signal component} 'in these signals can be derived from the

large signal-to-noise ratio of the sequential color signal on 25 signals G, R, B according to equation (1)

The cost of a complete correction of Ym is set, as is necessary for a true-to-color reproduction.

Equation (1) is agile in the case of predominantly blue or green. With a phase switch 18 through

achieve proportion of the color image. a half-line frequency switching voltage 19 of the

The in F i g. 4 shown display circuit clock generator 11 from line to line between +90 and

processed instead of the signals R, G, B in an analogous way 30-90 ° is switched, the for the PAL color

the signals R *, G *, B *. carrier necessary line-frequency reversal of the

The signal Fr-y recorded on the recorder 1 reaches. Where applicable, in the

Signal according to FIG. 1 is by means of a low-pass filter 2 stages 23 and 24 amplified signals Fb-y and

and a high-pass filter 3 in the signals Yh and R *, G *, F _± ur-y) then result in the adder 4 in the mo-

B * split. Yu is added to an adder level of 4 color carriers.

leads. The sequential signal R *, G *, B * is shown in FIG. 5 shows the basic structure of the matrix 10.

the signals Fr *, F _r *, F _b * are a resistance

Generated color carriers modulated and fed to the serial matrix 20.

circuit of two delay lines 7, 8 trains- This is dimensioned so that at its output 21

leads, to which a switch 9 is connected, which of 40 the luminance signal component Y * in the aggregate

a clock generator 11 is produced by the line-frequency implementation according to equation (1). This will be ir

pulse 12 in a known manner (DT-AS 12 56 686) so subtracting stages 16, 17 from the respective color carrier

is controlled that at its three outputs constantly frequency color signal Fb * and Fr * subtracted, se

the color carrier frequency signals F ₀ *, Fr *, F _B are available. that at the exit of these stages the color subcarrier

The color subcarrier-like color signals from the input, 45 quent signals Fb-y and F _R -y are available, which are then

Center and end of the series connection from the ßend, as in F i g. 4 shown, for PAL color

Delay lines 7, 8 are put together to form an adder carrier.

In addition 4 Blaii drawings

Claims (6)

signal with opposite sign added. Claims: are added when this exceeds a predetermined signal level. 1. Method for predistortion of a tri-line sequential color television signal which is assigned a 5
Switching into an FB AS color video signal containing luminance signal (Ym) and color difference signals is transformed, in which by means of line delays Approximation lines and line-frequency switches each repeat a color signal in its dead times io
is and the luminance signal (Ym) of the composite signal overall by summing the sequential color signals of three successive lines in order is, and a narrow-band transmission or Aufwonnen the luminance signal component (Y) drawing to permit a color television signal, the color difference signals (R-Y, B Y) in a 15 it is known (DT-AS 12 56 686), three different such other amplitude ratios than the color components representing color signals in a luminance signal (Ym) from three sequential color so-called three-sequence line by line is composed of signals that are in the (trizeilensequentiell) to transmit or record playback circuit in the matrixing color and for the playback by means of two line-true image rendering effecting color difference ao delay lines and three line-frequency signal signals, thereby repeating marked each in their dead times. There are nets that the trizeilensesequentlichen color television then all three color signals are constantly available and signal an additional signal (Z) at least in proportions can be added by matrix circuits in the desired, the color signals (R, G, B) with signals, ζ. B. a composite signal, are converted, contains such an amplitude that with Addi- 25 Here it is also known (DT-AS 12 61 876), the tion of the sequential line-sequential transmission containing the additional signal only for the deep partial color signals to make a luminance signal (Ym) frequencies of about 0 to 0.5 MHz, which is equal to the luminance signal (Y) and a luminance signal containing the high frequencies of about 0.5 to 2 MHz of the corresponding black and white television signal in each line. 30 transmitted or recorded. 2. The method as claimed in claim 1, in which the general task is to create a simple luminance signal (Ym) by temporal output circuit for obtaining a composite signal from three sequential color signals obtained from the trizeline sequential signal, which becomes a thereby characterized that the luminous causes good image reproduction. density signal (Y _M ) the form Y _M = 0.59 G + 0.3 R 35 It is already known (DT-AS 19 36 594) at a + 0.11 B. Circuit for converting a three-line sequential 3. The method according to one of the preceding color television signals in a simultaneous, a luminance claims, characterized in that the color television signal containing the signal, in the case of the means Additional signal (Z) is limited in such a way that line delay lines and line frequencies the three sequential 4 ° switches containing the additional signal (Z) each have a color signal in its dead times tial color signals a predetermined signal level is repeated, the luminance signal by Addinicht exceed or fall below. tion of the direct, the by a line and the by two 4. Method of obtaining a delayed sequential signal according to one of the preceding lines. Claims, characterized in that the said luminance amplitude of the tri-line sequential color signal 45 is preferably composed of equal parts of the three sequential color signals R, G, B before adding the additional signal (Z). This reduction in luminosity and the color density signal contained in the additional signal are also used to form the components and the color difference R — Y and BY in the display circuit. The color difference signals (RY, BY) formed have the particular advantage of being amplified from equal parts of jR, G, B. 5 ° composite luminance signals result in 5. Circuit for carrying out the method simplifications in the playback circuit and Vernach Claim 1, characterized in that improvements in image reproduction, in particular in the trisequentielJen color signal the additional horizontal or inclined edges. signal-forming color signal components with an ad- It has already been proposed (DT-OS dierstufe (40) are added and that means 55 19 43 672), in order to additionally improve the color to assess the amplitude of the fidelity of the reproduced image and to achieve a the color signals (36 to 38) are provided. still occurring in the proposed circuit To eliminate 6. A circuit according to claim 5 for carrying out deviation in hue, the Leuchtdes method according to claim 3, marked by tight signal component Y of the color difference signals RY, characterized in that a limiting means (36α, 6o Β- Y in such other amplitude ratio 37a, 38a , 41) is provided, which compose the signal level as the luminance signal Ym from the three sequential color signals contained in the additional signal (Z) that are reduced into signal components that are added to the sequential color-color signal with the same sign during the matrixing of the reproduction circuit Color differences that cause true image reproduction will be achieved if these result in a predetermined signal. level exceeds and / or the signal level of the object of the present invention is to mil those color signal contained in the additional signal - such a circuit the generation of a composite video proportions reduced, the effect of the sequential color video signal, which also with regard to