DE2158218B2 - Pre-distortion cct for three line sequential colour TV signal - designed for cct converting this signal in FBAS signal - Google Patents

Abstract

The pre-distortion circuit applies to a three line sequential colour television signal which is converted to a light intensity signal and a FBAS colour video signal containing colour difference signals. A colour signal is repeated in the dead time points by means of line delay lines and line frequency switches. The illumination signal of the FBAS signal is produced from three sequential lines by addition of the sequential colour signals. The light intensity signal portion of the colour difference signals is brought together from a different amplitude relationship than that of the illumination signal of the FBAS signal. Colour difference signals reproducing accurate colour pictures are generated in the reproducing circuit by matrixing.

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 _P " _F , _r , -. _if,, " _Λ , _Λ

generated that the according to the additional application ^Fb ~ ^{lr = Fß + Fz} ~ ^{{Ft + Fz) (6)}

P 19 43 672.7-31 color saturation still occurring - 5 F _B * - Fy * = F ₃ -Fy (6a)

^fe n ^er ^ T ^C ^ ^L ^ u, - The following applies accordingly:

The invention consists then that the trizeüen-

sequential color television signal an additional signal Z, ^ b * - ^ V * = Fr-Ft (T)

that the color signals A, G, Jf with such an amplitude.

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 Y _M results, which is the same as the luminance applied, in which, for example, stall signal Y of the corresponding black and white television of the sequential color signals (G, R, B), which is 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 performing the knowledge that the luminance signal Ym is not dk of the method according to the invention and its appropriate form are based on Ym = 0.59G + 0.3Ä + 0 , 11 B (1) drawing explained.

It shows
but the form so F i g. 1 the triple-row 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 caused by the main application, recording medium is required line by line alternately from, for example, in a system with 0 to 0.5 MHz, the color signals R, G, B as well as in obtaining the FBAS color video signals from the range of 0, 5 to 2 MHz in each line a luminous sequential color signal (R, G, B), the original density signal Yh recorded.

i-color signals to be transmitted. Rather, they are sequential. 2 are at terminals 31, 32, 33, the

tial substitute color signals C *, R *, B * to use the color signals R, G,

seamlessly available from the original sequential color signals B in the range from 0 to 0.5 MHz.

are composed and the equation (2) in the With a rotating in direction 43 switch 34

Form y _m _ Q 22 (Q * -L r * _ ± _ ß * \ o _a ) the three color signals R, G, B are traced line by line.

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

Union sequential color signals G, R, B must be controlled by stage 35, which also provides identification pulses

Satisfy equation (1). Identification of the color signals emitted The color

From this it follows for an additional signal Z, which all signals are also assigned to the evaluation stages 36,

sequential color signals are evenly added <5 37, 38 supplied. The evaluated color signals that

which is to form the additional signal Z, for the case of complete alignment,

to the form (1): the so independent of the sequential color signal

₇ _ _n ,, _r (\ m ο min ri \ the ^{position of} the rotating switch 34 in the ad-

z - υ, Λ> C / - u, uj κ - Ό, ΐζ a (I) dierstufe 40 added. After in the adding

With 50 step 42 the identification pulses of the synchronization step 35

C * - r Λ.7 (A \ ^unc * ^ ^as luminance signal Yh = 0.5 to 2 MHz, the

~ ^{+ Δ} ^ ^a 'is available at terminal 30, the sequential

R * = R + Z (4b) color signal has been added, the resulting

Signal fed to the recording device 1.

^B * = B + Z (4c) ₅₅ S ₀ U d _as exceeding or falling below certain

. ,,. , ·. <-, .. / -, Xt-J τ uj-1. Amplitude values of the transmission channel for the

is Surrender will be avoided by using Equation (2a) for the luminance ^ _{n color} si nal _g, so

signal after determining and demodulating the color _{in the embodiment shown in FIG}

Sequential color signals transmitted at a _{carrier frequency : the creation of an} advantageous training

Ym * = 0.33 (G -f- R + B + 3 Z) (2b) 60 of the method according to the invention is advantageous if both

_, .... "., ._ ...., for example through a damping level 39 the original

For the color difference signals _nal ^ sequential color signal is true because of the Main around the Fakz.erung in the corresponding circuit of the patent _{tor Q is weakened and, Me} individual Farbsignalantcile 19 43 672.7-31 _{signaIZ contained} in the additional registration P by appropriate Fy * = 0 , 59 Fr * + 0.3 Fr * + 0.11 F _n * (5) 65 descriptive interpretation of the assessment levels 36 to 38 ... ,, ",.,,. ,. . . ... . increased by (1-C). The one made

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

Fy * = Fg + Fr + Fb + Fz = Fy + Fz (5a) sequential color sienal can be given by a

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 modified 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. This leads to a the signal to noise ratio of the sequential color signal not to be taken in 5 low frequencies from 0 to 0.5 MHz containing purchase, it is also with the aid of luminance signal Fy _M, which in a demodulator 14 of a non-linear discriminator circuit 41 and demodulated. In addition stage 4 with the luminous three additional adder stages 36α, 37α, 38α possible, density signal Yb is combined to the complete luminance in the manner of a regulation in case of over- or under-signal and a portion of the individual io terminal 15 connected to a crossing of predetermined amplitude values -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 flow, 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

Color signal components contained in the additional signal ver ao Fg *, Fr *, F _b * are 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 _B -y and F _R * -y * = Fr-y [after

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

By means of this limiting device, a signal component Y 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 F _R -y recorded on the recording device 1 is reached. 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 / J *, G *, F _± hr-y) then result in the adder 4 in the mo-

B * split. Yb is added to an adder 4 and modulated color carrier.

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

a modulator 5 a built in an oscillator 6 The signals F _G *, F _R *, F _B * are a resistance

produced color carriers are modulated and fed to the row 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 of the Lcuchtdschte 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 subtraction stages 16, 17 is controlled by the respective color carrier that constantly subtracting frequency color signal F _B * and Fr * at its three outputs, se

the color subcarrier-frequency signals Fg *, Fr *, F _b are available. that at the exit of these stages the farbträgerfre

The 1 [arbträgerfrequenten color signals from the input, 45 quenten signals F _B -y and Fr-y are available, which 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.

For this purpose 4 sheets of drawings

Ä7Q

Claims (1)

signal with opposite sign added Claims: will be if this has a predetermined signal level exceeds. 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 delay lines and line-frequency switches, a color signal is repeated in its dead times io
is and 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 (RY, BY) in the luminance signal (Ym) of the composite signal 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 (Y _M ) from three sequential color so-called triple sequence is composed line by line one after the other that in the (trizeline sequential) to transmit or record reproduction circuit in the matrixing and color difference for reproduction by means of two line-true image reproduction result in delay lines and three line-frequency sound signals, thereby repeating marked each in their dead times. There are net that the trizeilensequentielle Farbfemseh- 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, which the color signals (R, G, B) with signals such. B. a composite signal, are converted, contains such an amplitude that with Addi- 35 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 in that the luminous effect causes good image reproduction. density signal (Ym) 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 any 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 switches containing the additional signal (Z) each have a color signal in their dead times tial color signal 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 RY and BY in the display circuit. The color difference signals (RY, BY) formed have the particular advantage of being amplified from equal parts of R, G, B. 50 separately set luminance signals result in 3. Circuit for carrying out the process facilities in the playback circuit as well as according to claim 1, characterized in that improvements in image reproduction, in particular in the tri-sequential 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 6. A circuit according to claim 5 for carrying out discrepancies in the hue to eliminate the luminous of the method according to claim 3, characterized in that the characteristic density signal component Y of the color difference signals R - Y, shows that a limiting device (36α, 6o B-Ym such a different amplitude ratio 37ii, 38a, 41) is provided, which the signal levels as the luminance signal Ym from the three sequen of those color signals contained in the additional signal (Z) that ir Signal components reduced, which color the sequential of the playback circuit during matrixing. Color signal with the same sign added true image reproduction causing color difference when these result in a predetermined signal 65 signals. level exceeds and / or the signal level of the object of the present invention is to mil the color signal contained in the additional signal - such a circuit generates a composite video proportions reduced, which to the sequential color-color video signal. cause that also with regard to