SU1148127A2 - Device for introducing symbol information in colour television signal - Google Patents

Abstract

DEVICE FOR INTRODUCTION OF SYMBOL INFORMATION IN THE COLOR TELEVISION SIGNAL by auth. In 1007218, characterized by 4Toj, in order to reduce distortion in the color television signal, the output of the peak detector is connected to the second input of the first modulator via the third adder, the second input of which is combined with the input of the peak detector.

Description

The invention relates to television. According to the main author, No. 1007218, a device is known for introducing symbolic information into a color television signal containing a peak detector connected in series to an amplifier, an attenuator and a comparator, the first and second outputs of which are connected respectively to the first inputs of the first and second modulators, the second inputs which are connected to the amplifier output, and the outputs - to the first and second inputs of the first adder, the output of which is connected to the first input of the second adder through a low-pass filter, the second input of which is connected The output of the delay unit, whose input is connected to the output of the amplifier, while the second and third inputs of the comparator are connected respectively to the output of the amplifier and to the signal input of the symbol information ClJ The disadvantage of the known devices is the poor quality of the television signal being generated, which is shown in suppressing the main signal video signal when introducing symbolic information into it. The purpose of the invention is to reduce the distortion in the color television signal. I- :. .. The goal is achieved by the fact that in a device for inputting symbolic information into a color television signal containing an amplifier connected in series, a peak detector, a comparator attenuator, the first and second outputs of which are connected to the first and second modules correspondingly, the second the inputs of which are connected to the output of the amplifier, and the outputs of the first and second inputs of the first adder, the output of which is connected to the first input of the second adder through a low-pass filter, the second input of which With the code of the delay unit, whose input is connected to the amplifier output, the second and third inputs of the comparator are connected respectively to the output of the amplifier and to the input of the symbol information signal, the output of the peak detector is connected to the second input of the first modulator through the input third adder, the second input of which 71 is combined with the input of the peak detector. . The drawing shows a structural electrical circuit of a device for inputting symbol information into a color television signal. A device for inputting symbol information into a color television signal comprises amplifier 1, delay unit 2, first adder 3, second adder 4, peak detector 5, attenuator 6, comparator 7, first modulator 8, second modulator 9, low-pass filter 10 ( LPF) and the third adder 11. The device operates as follows. The color television signal, amplified by amplifier 1, is fed to the input of the block, 2 delays and to the signal generation channel of the symbols. The delay unit 2 is necessary to compensate for the delay in the signal in the signal form for the signal signal. The signal of the symbols is fed to the third (gating) input of the comparator 7, which distributes this signal to two inputs; for introducing on dark areas of the image and on light areas of the image, depending on the level of gray, generated at the output of the attenuator 6 and fed to the first (inverting) input of the comparator 7. At its second (non-inverting) input is a video signal from the output of amplifier 1 When transferring bright parts of the image from the second output of the comparator 7 to the first input of the second modulator 9, a sequence of pulses is received designed to form characters at the black level. The amplitude of the pulses at the output of the second modulator 9 corresponds to the current level of the video signal fed to its second input. From the output of the second modulator 9, the signal thus generated is fed to the second (inverting) input of the first adder 3 and then through the low-pass filter 10 to the first input of the second adder 4, in which this signal is subtracted from the full color signal, as a result of which characters, the signal value at the output of the device becomes zero, i.e. black level. When transmitting dark parts of the image from the first (inverse) output of the comparator 7 and to the first

the input of the first modulator 8 receives a sequence of pulses designed to form a simulated one in accordance with

fishing level

and UB - Uec, (1)

where and the output voltage of the third adder 11;

Ut is the voltage corresponding to the white level of the video signal generated by the peak detector 5;

The UBC voltage corresponds to the current value of the video signal.

From the output of the first modulator 8, the signal of the symbols, having an amplitude determined by the hyphenation (1), goes to the first (non-inverting)

input of the first adder. 3 and further through the LPF 10 to the first input of the second adder 4, at the output of which there is a signal of symbols with an amplitude determined by the output of

Usc- (b - UBC) B. 2)

and

ev

where U (.g- stresses, appropriate

white signal amplitude.

Thus, the introduction of a third adder into a device for inputting symbolic information into a color television signal can improve the quality of the generated television signal by clearly associating the white level of the input characters with the white level of the signal.

Claims (1)

DEVICE FOR INTRODUCING SYMBOL INFORMATION INTO COLOR TV SIGNAL according to ed. No. 1007218, characterized in that, in order to reduce distortion in the color television signal, the output of the peak detector is connected to the second input of the first modulator through the input? ” the third adder, the second input of which is combined with the input of the peak detector.