SU756667A1 - Television colour synthesizer - Google Patents

Description

The invention relates to television and can be used as a generator of the test signal in the study of color quality. five

Known television color synthesizer, 'containing the reference voltage source; connected to the first input of the adder, the corresponding inputs of which are connected to the first and second 10 inverters, respectively II] • RD-. However, this device has a low speed.

The purpose of the invention is to increase the speed, the device. 15

To do this, a television color synthesizer containing a voltage source connected to the first input of the adder, the corresponding inputs of which are connected to the first 20 and second inverters, respectively, introduces a first delay unit, the input of which is sent to the first clock pulses, and the output is connected to the first sawtooth generator, 25 the other input of which is connected to the input of the adder, and the output - to the input of the first inverter and the first input of the input switch, the second input of which is connected to the output of the adder

2

and the third input - with the output of the second inverter and the output of the inputted second sawtooth generator, one input connected to the input, an adder, another care output of the input second delay unit, input of which sync pulses are fed, in addition, the control input of the switch is connected to the output of the entered comparator, the first input of which is connected to the output of the adder, and the second input - to another output of the reference voltage source.

FIG. 1 shows a block diagram of the proposed device? in fig. 2 - view of the image formed on the screen of the color kinescope.

The television color synthesizer contains the source 1 of the reference voltage, the adder 2, the inverters 3, 4, the delay unit 5, b, the generators 7, 8 sawtooth voltage, the switch 9, the comparator 10.

Television color synthesizer works as follows.

It is known that the condition for the chromaticity diagram with an arbitrary color module T

3

756667

u + u ₂ + u, = τ,

where and ₁ , and ₂ , and _e - color-separated signals, and the coordinates of the points of the chromaticity are defined as:

divided signals to the output of the synthesizer. ,

Since in the scheme of a color synthesizer, generators 7.8 of sawtooth voltage, triggered by clock pulses, are used, as the image is scanned, the amplitudes of the color-separated signals are twisted. If ν _μ = T, then

Therefore, to form an entire gamut of chromaticity during one frame, it is necessary to associate an image scan with modulation of output signals determining the color of the synthesized image, i.e. when = 114 (1) ^{and =} we get m = m (0 and η = η (ϊ).

The source produces a constant voltage Ui high stability; the value of _and may vary. The voltage from source 1 is supplied to the adder 2 and simultaneously to the generators 7.8, for which the voltage ν _μ determines the amplitude of the sawtooth voltages. Generators 7.8 are started by synchronizing pulses, coming through delay blocks 5 and 6. The duration of sawtooth pulses in each generator 7.8 is determined by its parameters.

If the constant voltage at the output of source 1 is of positive polarity, then the generators 7,8 form linearly rising voltages. Pz ^ st is the duration of the horizontal sawtooth voltage with _с <4 / £ _с , where £ _с is the horizontal scanning frequency, and personnel frequency <4 / ίχ, where £ _к is the vertical scanning frequency. Then for generator 7, the output voltage is written as

= and _with (1) = -pa for generator%

- 1) q ι

These two voltages are fed to the switch 9 and through inverters 3,4 and adder 2 "Therefore, the voltage at the output of the adder 2, which is also fed to the switch.-9, is defined as

ten

15

20

25

thirty

35

40

45

^and s = u (u = u _to - and _b (ι) -and (v) = ν _Μ [ιг ~ ⁺ ( ¹ " ^{a 1} ) ·. 50

where a = t- + r- “some constant mf FC

coefficient depending on the image format on the screen of the kinescope.

In a great way, the voltage I) (ι) is also linearly varying, but with a negative coefficient, i.e. falling. This voltage enters the comparator 19, the second input of which is fed zero reference voltage from source 1. When the condition

and _and (ι -a1) o '

the comparator 10 is activated and closes the switch 9, interrupting the flow of color

t = 4 / ί _ε · {, η = ί / -Ε _κ -ϊ,

those. The chromaticity coordinates of the elements in the imaged image are functions of time, consistent with the laws of television decomposition. When these signals are sent to a color picture tube, an image of a triangle is formed on the screen, the chromaticity of each point of which depends on its spatial coordinates. This triangle will correspond to the chromaticity diagram of the selected colorimetric system with a color module constant for all chromaticities. To change the color module, you must change the voltage of Mu.

The beginning of the formation of a chromaticity diagram can be moved to the image field using delay blocks 5 and 6, and any color can be sent to any point on the screen of the kinescope, therefore, the color reproduction can be evaluated anywhere on the screen.

Thus, the introduction of two generators 7.8 sawtooth voltage and a comparator 10 to control s? <We color-separated signals, as well as synchronization of these generators 7,8 from personnel and horizontal clock pulses, allowed us to increase the speed of formation of the test signal for color television systems so that implement it during one frame of television decomposition. When this is achieved, orderliness in the arrangement of chromaticities in accordance with the chromaticity diagram and the possibility of independent adjustment of chromaticity and color modulus is retained. All this leads to an acceleration of the research process and creates prerequisites for objective ¹ and prompt assessment of the quality of color reproduction and color reproduction of color kinescopes and entire television systems ..

Claims (1)

Claim A television color synthesizer containing a voltage source connected to the first input of the adder, the corresponding inputs of which are connected to the first and second inverters, respectively, characterized in that, in order to improve device performance, the first delay unit is inserted, the input of which is lowercase clock pulses and the output connected to the first generator sawtooth5 756667 6 voltage, the other input of which is connected to the input of the adder, and the output of the input of the first inverter and the first input of the input switch, the second input of which is connected to the output of the adder, and the third input - to the output 5 The second inverter and the output of the input second generator sawtooth voltage, one input connected to the input of the adder, and another input to the output of the input of the second delay unit, the input of which is fed frame sync pulses, in addition, the control input of the switch is connected to the output of the entered comparator, the first input of which is connected to the output of the adder, and the second input to another output of the reference voltage source