RU1817257C - Device for displaying complementary color television images - Google Patents

Abstract

The invention relates to television technology, and in particular to color television receivers. The aim of the invention is to reduce the distortion of an additional image while simplifying the device. The device for reproducing additional television images includes an electronic switch 1, a luminance channel 2, a color channel 3, an additional image clock selector 4, a multiplexer 5, an analog-to-digital converter 6, an adder 7, a first memory unit per line 8, an addressing unit 9, a multiplier 10 , the second memory unit on line 11, the addressing unit 12, the demultiplexer 13, the addressing unit 1.4, the memory unit on the field 15, the second, third, fourth digital-to-analog converters 16, 17, 18, matrix 19, the controller 20. In the device enes additional image distortion caused by interference of the direct and delayed signal averaging adjacent lines of the luminance signal reduces the sampling noise. 7 ill.

Description

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The invention relates to the technique of television and, in particular, to television receivers.

The aim of the invention is to reduce the distortion of an additional image while simplifying the device.

In Fig. 1, a functional diagram of the proposed device is given; Figures 2, 3, 4 explain the processes of processing the multiplexed signal in the SECAM, PAL, and NTSC modes. In FIG. 5 shows an example of the implementation of the color channel of the proposed device. FIG. 6 is an exemplary embodiment of a controller 20. Finally, FIG. 7a-7d illustrate the conversion of vertical spatial spectra in the prototype (7a-7c) and in the proposed device (7g-7d).

Consider figure 1. The proposed device contains an electronic switch 1, the inputs of which receive signals from additional image sources, the output is connected to the inputs of the luminance channel 2, a multi-standard color channel 3 without an ultrasonic delay line and with an additional image clock selector 4. The outputs of brightness 2 and color 3 are connected to the signal inputs of multiplexer 5, the output of which is connected to the input of an analog-to-digital converter (ADC) 6. The output of the ADC is connected to the first input of adder 7 through memory 8 to a line with address block 9, and to the second input adder 7 - directly. The output of the adder 7 through an adjustable multiplier 10 by a factor K is connected to the input of the storage device 11 per line with the addressing unit 12. The output of the link 11 is connected to the input of the demultiplexer 13, to the outputs of which the memory in field 15 is connected with the addressing unit 14. The outputs of the memory in the field are connected via digital to analogue conversion vi

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Whether 16, 17, 18 with inputs, an RGB signal matrix 19, Controller 20 is connected to all storage devices, addressing units, multiplexers, a multiplier 10, as well as a color channel 3 and the output of the clock pulses 4. Gating clock pulses of the primary and secondary are applied to controller 20 images. The outputs of the RGB matrix, as well as the output of the controller 20, which generates a signal from the reading window of the contents of the memory on the field, during which additional images are displayed on the screen, are the outputs of the device. Link 1 is a conventional analog switch that is controlled by voltage V1. The luminance channel 2 may comprise a black level fixation circuit, tuning span and level adjustments, as well as a microsecond delay line to compensate for the delay of the color signal, and a notch filter that suppresses the color signal.

The color channel 3 can be made (Fig. 5) in the form of a serial multi-standard processor SECAM / PAL / NTSC 21, for example, on an integrated circuit TDA4555, with a bandpass filter 22 at the input, in which the ULZ is excluded, and the input of the delayed signal is connected by alternating current with case.

Multiplexer 5 - analog type such as, for example, KR561KTZ.

The analog-to-digital converter 6 may be of the type K1107PV1. Storage devices 8 and 11 may be random-accessed static, for example, KR541RU2A. The storage device 15 can be performed on a dynamic type RAM, for example, K565RU6B. The addressing blocks 9, 12. 14 can be made in the form of binary counters.

Digital to analog converters 16-18 can be of type K1118PA1. the multiplier 10 by the coefficient can be performed on the IP K531KP11 or on the shift register K531IR20. Demultiplexer 13 can be performed on the register K531IR18. Matrix 19 is implemented in the usual manner as resistive adders or on a serial IC such as TBA530. The controller 20 may be configured as shown in FIG. 6. It contains a clock generator 23, which generates clock signals UT of various frequencies supplied to the ADC 6 and memory addressing units, as well as IMv, U / ju signals. U4Y. supplied to multiplexer 4 and demultiplexer 12, a logic unit 24 generating a signal V5 controlling the multiplier 10, and a window generator 25 controlling the addressing unit 14 of the memory in field 15 in the read mode. Consider the operation of the proposed device by switching the switch 1 signal Ui, choose one of the sources of the additional signal (additional radio channel, VCR, video disc, etc.). In block 2, a luminous component is extracted from the entire video signal, which is amplified to the required amplitude and delayed in time until it matches the demodulated color-difference signals U and V formed by the color channel 3,

5 Since in link 3 there is no ULZ, at its outputs in SECAM mode alternating lines of signals U and V are distinguished. In PAL mode, signals U and V are present every line, but phase-distortion is not compensated in them, and the range was 1/2 of the nominal, when the NTSC signal is received, at the output of link 3, U, V signals with a nominal amplitude are extracted. Link 3 also generates logical control signals U2, Uz corresponding to the received color television system, for example, 00-SECAM, 01-PAL, 10-NTSC.

The selector 4 generates from the full video signal 0 the combined strobe pulses SSC of the additional image. As a selector 4, the serial microcircuit K174XA11 can be used. In the multiplexer 5 signals Y, U, V under

5, by the action of control pulses, IMu, UUv, U4Y from block 20 are converted into a sequence, which in the SECAM mode for the first line has the form YH, Un, Yi2,0, Via, Ui3, Yi4, 0, ..,. Multiplexed

0, the signal is digitized in the ADC b. The obtained sequence of samples (Fig. 2a) is stored in the memory 8. The multiplexed signal of the second line has the format shown in FIG. 26. In it

5 only the color component V (ER-Y) is present. When the second line passes, the signal of the first line is read from the memory 8, and the signal of the second line is written in its place, which is simultaneously fed to the adder 7. A signal is obtained at the output, the format of which is shown in Fig. 2c.

The samples of the brightness signal at the output of the adder Yi, Y2, Ya, ... are the sums of adjacent samples of two adjacent rows, for example, Yi Yn + Yyt. The amplitudes of these samples are doubled. The multiplier 10 in the SECAM mode is controlled by the signal of FIG. 2g When passing samples Y, this signal takes a value equal to a logical unit, and the multiplier 10 changes its transmission coefficient from 1 to 0.5. This ensures that the luminance signal is brought to its nominal value. At the same time, quantization noise is reduced.

In the signal at the output of adder 7 there are color components U and V with a nominal amplitude.

Thus, the new circuits introduced into the device — memory 8 with addressing unit 9, adder 7 and multiplier 10 by an adjustable coefficient — provide restoration of the missing color information and averaging of the brightness signal.

The signal of FIG. 2c is supplied to the memory device 11 per line. Further, signal processing is carried out in the same way as in the prototype. Only part of the lines, for example, the first, fifth, ninth, etc., are recorded in memory 11. In the time intervals between recordings, information from the memory 11 is read out, demultiplexed to components U, V. Y in link 13 and simultaneously recorded in the memory on field 15. In the selected area of the main image, the signals recorded in memory 15 are read out with an enlarged one, for example, 4 times, by speed, it is converted with help (by the DAC 16-18 into analog form, it is converted in matrix 19 into RGB signals, which are input into the main channels of the TV's RGB during the Wokne signal produced by the controller using in microcircuits, for example K174XA17, keys. Performan on the TV screen in a predetermined place there is a reduced color image further.

If the input of the proposed device receives the full color signal PAL, then at both outputs of the color channel 3 signals U and V are simultaneously distinguished. Since the ULZ is excluded from the color channel, the differential-phase distortions in these signals are not suppressed, and the signal amplitude is half as much face value. At the input of the multiplexer 5, during the transmission of the first and second lines, signals are extracted, the format of which is shown in FIG. 3 a, b. These signals are digitized and fed to memory 8 and adder 7. At the output of the adder, the signal of FIG. Sv, in which both the samples of the luminance signal and the samples of the signals U, V are averaged. Averaging of the color signals compensates the differential phase. Averaging the samples of the brightness signal, followed by dividing by 2 in link 10 reduces the sampling noise. Further processing is carried out as in the SECAM mode.

When processing the NCC signal, the amplitudes of the components U and V at the output of the color channel 3 are equal to the nominal value. Therefore, in the NTGC mode, a logical unit is fed to the control input of the link 10, which provides for two signals of both the brightness signal and the samples of the signals U and V.

In order to reduce moire distortion of the image, the summation of the video signal of adjacent lines using the link 7 used for processing color-difference signals is applied, and the current line is added to the previous one.

In a signal processed in this way, out of every four lines in the memory 11, one line is written, which is used to form a line of a 4 times compressed additional image. This operation corresponds to low-frequency vertical filtering of a video signal spectrum. As shown in FIG. 7d, the selection of two lines of four and their summation leads to a halving of the vertical sampling rate of the signal and to narrowing of the low-frequency component of the signal spectrum, thereby significantly reducing the overlap of the low-frequency and high-frequency components. After writing to the field memory and then reading it at a quadruple frequency, the signal spectrum expands and takes the form of FIG. 7d The ratio of the useful component and the interference from the high-frequency harmonics in the low-frequency part of the spectrum is much higher here than without summing the adjacent lines. In addition, due to the high correlation of the video signal in adjacent lines, the ratio of the useful signal to the fluctuation noise increases during summation, which also improves the image quality.

Thus, in the proposed device, the distortion of the additional image caused by the echo signals in the ULZ and direct and delayed signal interference in the prototype is eliminated. Averaging adjacent lines of the brightness signal reduces sampling noise in this device and increases the signal-to-noise ratio. In the proposed device, simplification has been achieved by replacing the precision and expensive ULZ PAL / SECAM with memory 8, as well as the use of Y, U. V signal processing instead of wider RGB.

Finally, the exclusion of the ULZ device in the proposed device increases the degree of its integration and allows a significant part of the device to be implemented as a single VLSI.

This ensures the achievement of the object of the invention — reduction of distortion of the sub-image while simplifying the device.

Claims (1)

The claims A device for reproducing additional color television images containing an electronic switch, the output of which is connected to the inputs of the brightness and color channels and to the input of the selector clock of the additional image, the output of the brightness channel, as well as the first and second outputs of the color channel are connected respectively to the first, second and third inputs the first multiplexer, the output of which is connected to the first input of the analog-to-digital converter, the output of the clock selector is connected to the first input to the controller, to the second input of which the gating pulses of the main image are applied, the third and fourth inputs of the controller are connected to the third and fourth outputs of the color channel, the first, second and third outputs of the controller are connected to the fourth, fifth and sixth inputs of the multiplexer, as well as to the first, the second and third inputs of the demultiplexer, the fourth output of the controller is connected to the control input of the ADC. the first input of the first memory block per line is connected to the fifth output of the controller, the address inputs are connected to the outputs of the first addressing block, the input of which is connected to the sixth output of the controller, the output of the first block memory per line is connected to the fourth input of the demultiplexer. two outputs of which are connected to the first and second inputs of the memory unit in the field, to the third input the memory block on the field is connected the output of the second addressing block, the first and second inputs of which are connected to the seventh and eighth outputs of the controller, the three outputs of the memory block on the field are connected respectively to the inputs of three digital-to-analog converters, the outputs of which are connected to the inputs of the RGB matrix, matrix outputs, as well as the eighth controller output are device outputs, inputs electronic switchboard are the inputs of the device, characterized in that, in order to improve the quality of the additional image, a second memory unit per line, a third addressing block, is introduced. the adder and the controlled multiplier, the output of the analog-to-digital converter is connected to the first input of the adder through the second memory block per line, and to the second input directly, the output of the adder is connected to the first input of the controlled multiplier, the output of which is connected to the input of the first memory block per line, while the control inputs of the multiplier, the second memory block per line and the third block the addresses are connected respectively to the ninth, tenth and eleventh outputs of the controller. -A 4 L 00 1817257 CEKfiM and) 5) 6) g) a) 6) b) d) and) 5) 6) g) 22 U6x, PF ll Fiz. 5 srig, 4. {UAZ} -IH V e / U v U li and and 1817257 Ut 11 € 2o original b