RU2013888C1 - Digital device for separating color and brightness signals in secam decoder - Google Patents

Abstract

FIELD: TV engineering. SUBSTANCE: device has analog-to-digital converter 1, unit 2 for separating total color videosignal to low-frequency and high-frequency components, two delay units 3, 16, adder 4, three digital-to-analog converters 5, 15, 18, two multipliers 6, 8, vertical filtration unit 7, unit 9 for measuring color subcarrier rest frequency, complex envelope corrector 10, color subcarrier rest frequency complex signal generator 11, complex envelope frequency detector 12, electron commutator 13 and two low frequency distortion correctors. EFFECT: reduced distortion of color and brightness. 1 dwg

Description

 The invention relates to the field of television, in particular to devices for separating luminance and color signals in decoders of the SECAM system, and can be used in analogue-digital hardware-studio complexes of television broadcasting and television broadcast receivers.

 The device is intended for separation of luminance and color signals in digital decoders of the SECAM system.

 A device for separating luminance and chrominance signals in a decoder is known, which comprises a first delay unit and an adder connected in series, a second delay unit and an electronic switch connected in series.

 A disadvantage of the known device is the presence of distortion of luminance and color signals.

 The aim of the invention is to reduce the distortion of luminance and chrominance signals.

 The goal is achieved by the fact that an analog-to-digital converter, the input of which is the input of the full color video signal (PCVS) and the block for the separation of the PCVS into low-frequency (LF) and high-frequency (HF) components, the LF output is connected to the input of the first block is additionally introduced into the device delays connected in series to the first multiplier, the first input of which is connected to the output of the RF component of the separation unit of the PCVS into RF and LF components, the vertical filtering unit and the second multiplier the output of which is connected to the second input of the adder, the output of which is connected to the input of the introduced first digital-to-analog converter (DAC), the output of which is the output of the luminance signal, a series-connected unit for determining the resting frequency of the color subcarrier, the input of which is connected to the first input of the first multiplier, and a generator of a complex signal of the quiescent frequency of the color subcarrier, the first and second outputs of which are connected respectively to the second inputs of the first and second multipliers, connected in series a complex envelope corrector, the input of which is connected to the second output of the vertical filtering unit, and a frequency detector, the output of which is connected to the input of the second delay unit and the second input of the electronic switch, the first corrector of low-frequency predistortions, the input of which is connected to the first output of the electronic switch, is connected in series, and the second DAC, the output of which is the output of the first color difference signal (RY), and the second corrector of the low-frequency predistortions, the input of which is connected to the second the output of the electronic switch, and a third DAC, whose output is the output of the second color difference signal (B-Y).

 The drawing shows a structural diagram of the proposed device.

 It contains ADC 1, block 2 of the separation of the PCVS into LF and HF components, the 1st and 2nd delay units (BZ) 3 and 16, the adder 4, 1st, 2nd and 3rd DAC, 1st and the 2nd multipliers 6, 8, the vertical filtering unit 7, the color subcarrier quiescent frequency determination unit (BCCH), the complex envelope corrector 10, the complex subcarrier quenching frequency generator 11 (GCCHP), the complex envelope frequency detector 12 (BH KO ), electronic switch (EC) 13, 1st and 2nd corrector LF predistortion 14 and 17.

 A chain of series-connected ADC 1, block 2 separation of PCVS into low and high frequency components of the 1st BZ 3, the adder 4 and the 1st DAC 5 is connected between the input of the device and the output of the brightness signal. A chain of sequentially connected 1st multiplier 6, vertical filtering unit 7, 2nd multiplier 8 is connected between the 2nd RF output of the PCVS separation unit for LF and RF components and the 2nd input of the adder 4. The input of the GCCHP 11 is connected through the BCHP 9 with a 2-nd high-frequency output of a block 2 for dividing the PCVS into LF and HF components; The 1st and 2nd outputs of the GCCHP are connected to the 2 inputs of the 1st 6th and 2nd 8th multipliers, respectively. A chain of series-connected corrector of the complex envelope 10 and BH KO 12 is connected between the 2nd output of the vertical filtering unit 7 and the 1st input of EC 13; The 2nd input of the EC 13 is connected to the output of the BH KO 12 through the 2nd BR 16, and the 1st and 2nd outputs of the EC 13 are connected respectively through the 1st corrector of the low-frequency predistortions of the 14th and 2nd DACs of the 15th and 2nd corrector LF predistortion 17 and 3rd DAC 18 with the outputs of color-difference signals RY and BY.

 The device operates as follows.

 The full color video signal using the ADC 1 is converted to digital form.

 Using block 2 separation PCVS on the LF and HF components carry out the specified separation so that the LF part of the signal in the band 0. . 3 MHz, which is fed to the first input of adder 4 through 1-q БЗ 3, which serves to coordinate signal delays in parallel branches, and is added to the RF part of the signal, in which the spectrum of the color subcarrier is notched, and the resulting luminance signal is generated at the output of adder 4 , which is converted to analog form using the 1st DAC 5.

 The RF part of the PCVS from the separation unit is fed to the 1st input of the 1st multiplier 6 and to the input of the control unit 9.

In the 1st multiplier 6, a complex multiplication of the RF part of the signal and the 1st complex signal of the color subcarrier W _R (t) or W _B (t) from the generator of the complex signal of the color subcarrier quiescent frequency, which is controlled by the color subcarrier quiescent frequency determination unit, is performed (f _R or f _B ). As a result of multiplication, the spectrum of the HF part of the signal is transferred such that the quiescent frequency of the FM color signal contained in this signal is transferred to the zero frequency and fed to the input of the vertical filtering unit 7.

 In the vertical filtering unit 7, the RF component of the PCVS is divided into luminance and color components in such a way that in those lines where the phases of the subcarriers are opposite, a luminance signal (1st output) and a color signal ( 2nd output), and in those lines where the phases of the subcarriers are the same, the distortions appearing as jaggedness on inclined boundaries are reduced using interpolation of adjacent lines and replacing the current line with the interpolated one.

 From the 1st output of the vertical filtering unit 7 after the reverse frequency transfer in the 2nd multiplier 8, the RF component of the brightness signal, in which the stroboscopic phenomena associated with the discrete line structure of the digital video signal are weakened, is fed to the 2nd input of the adder 4.

 From the 2nd output of the vertical filtering unit (7), the complex color subcarrier signal through the complex envelope corrector, which compensates the amplitude modulation introduced by the RF circuit, is fed to the BH KO 12 input, the output of which is a sequence of color-difference signals R-Y, B-Y. Using the 2nd BZ 16 and EC 13, this sequence is converted into a sequence of signal lines R-Y and B-Y. In the 1st 14th and 2nd 17th pre-emphasis low-frequency correctors, the distortions introduced during the coding of color difference signals are compensated, and using the 2nd 15th and 3rd 18th DAC, these signals are converted to analog form.

Claims (1)

 DIGITAL BRIGHTNESS AND COLOR SIGNALING DEVICE DEVICE IN SECAM SYSTEM DECODER, comprising a first delay unit and an adder connected in series, a second delay unit and an electronic switch connected in series, characterized in that, in order to reduce the distortion of the luminance and color signals, analog-to-digital are connected a converter whose input is an input of a full color video signal (PCVS), and a block for dividing a PCVS into low-frequency (LF) and high-frequency (HF) components, you the path of the LF component is connected to the input of the first delay unit, the first multiplier is connected in series, the first input of which is connected to the output of the RF component of the separation unit of the PCVS into HF and LF components, the vertical filtering unit and the second multiplier, the output of which is connected to the second input of the adder, the output of which is connected with the input of the entered first digital-to-analog converter (DAC), the output of which is the output of the luminance signal, the unit for determining the frequency of rest of the color subcarrier is connected in series whose input is connected to the first input of the first multiplier, and the generator of a complex signal of the quiescent frequency of the color subcarrier, the first and second outputs of which are connected respectively to the second inputs of the first and second multipliers, sequentially connected to the complex envelope corrector, the input of which is connected to the second output of the vertical filtering unit , and a frequency detector, the output of which is connected to the input of the second delay unit and the second input of the electronic switch, the first corrector is connected in series OR low-frequency predistortion, the input of which is connected to the first output of the electronic switch, and the second DAC, the output of which is the output of the first color-difference signal (R - Y), and the second corrector of low-frequency predistortions, the input of which is connected to the second output of the electronic switch, and the third DAC whose output is the output of the second color difference signal (B - Y).