SU1748287A1 - Device for non-linear processing of color-different signals in secam coder - Google Patents

Abstract

The invention relates to television technology and can be used in the apparatus for generating the full color signal of the SECAM system. The aim of the invention is to reduce distortion of color difference signals. The device for nonlinear processing of color-difference signals in the SECAM system encoder contains predistortion block 1, analog-digital converter 2, block 3 for limiting and expanding the signal, pulse duration measuring unit 4, control signal shaper 5, control low-pass filter 6, digital signal limiter 7, block 8 subtractors, three delay units 9, 10 and 11, an adder 12 and a digital-analog converter 13. The goal is achieved by expanding a limited selection, which allows the transfer of information about the energy th ejection, and at the receiving side, respectively, to more accurately perform recovery tsvetorazmostnogo signal during decoding. 1 il. (A C

Description

The invention relates to television technology and can be used in apparatus for generating the full color signal of the SECAM system.

The aim of the invention is to reduce the distortion of color difference signals.

The drawing shows a structural electrical diagram of a device for correcting color difference signals in the encoder of the SECAM system.

The nonlinear color-difference signal processing device with the SECAM system encoder comprises a predistortion unit 1, an analog-to-digital converter (ADC) 2, a signal limiting and expanding unit (BORS) 3, a pulse duration measuring unit (BIDI), a control signal generator 5 (FSU), controllable low-pass filter 6 (UFN), digital signal limiter 7 (OTsS), subtraction unit 8, three delay units 9-11, adder 12 and digital-to-analog converter (DAC) 13. Non-linear processing of color-difference signals in the encoder of the SECAM system r It works as follows.

An analog color difference signal through predistortion unit 1, in which standard CE systems are implemented. KAM low-frequency predistortion, 30 goes to the input of the ADC 2, which is converted to digital form. From the output of the ADC 2, the signal goes directly to the input of the BARS 3, which consists of a signal expansion unit and a multiplexer. In BORS 3 35, non-linear processing is performed, which consists in limiting emissions and expanding them by digitally accumulating limited emissions. A rectangular impulse is formed at the output of the BORS 3 control, corresponding in duration to the duration of the limited and extended ejection.

A color difference signal is formed at the information output of BORS 3, corresponding to the input signal in 45 monophonic sections, а. during the color transition corresponding to the processed signal. The limited OTSS 7, in accordance with the standard for the SECAM system, the color difference signal through the first delay unit 9 is fed to the subtraction unit 8, in which it is subtracted from the output signal. BORS 3, as a result of which a signal is generated at the output of the subtraction block, corresponding to the extended part of the ejection from the color transition. The specified signal through the third block 11 delay arrives at UFNF 6, the bandwidth of which varies in accordance with the duration of the pulse measured by BIDI 4, so that with a short duration (less than 0.5 μs) of the pulse, the bandwidth of UFNF 6 is maximum, and with a duration of 5 corresponding to a deep emission limitation (more than 1 μs), the passband is narrowed and the signal at the output of the UHF 6 is smeared.

This is achieved by the fact that the digital code 10 BIDI 4 is converted into FSU 5, made, for example, in the form of ROM, into a set of coefficients that determine the operating mode of the UFN 6. . ’

The output signal of the UFNF b is summed 15 in the adder 12 with the main signal supplied to its second input through the third delay unit 11, and then through the DAC 13 is fed to the output of the device.

The extension of the limited outlier 20 makes it possible to transmit information about the energy of this outlier, which, in turn, allows the color-difference signal to be restored more accurately during decoding on the receiving side. In this case, 25 in the case of a weak and medium restriction, a reduction in the duration of the color transition is achieved, and with a strong restriction, it becomes possible to significantly reduce the stretching continuations.

Claims (1)

Claim A device for non-linear processing of color-difference signals in an encoder of the SECAM system, which contains a series-connected predistortion unit, an analog-to-digital converter (ADC) and a signal limiting and expanding unit, as well as a digital-to-analog converter (D / A), 40 C onclusion that, in order to reduce distortion of color-difference signals, a pulse-width measuring unit, a control signal generator, a controlled low-pass filter and an adder connected in series are introduced in series a digital signal limiter, first and second delay units, as well as a subtraction unit and a third delay unit connected in series, while the input of the pulse width measuring unit is connected to the control output of the signal limiting and expanding unit, the input of the digital signal limiter is connected to the ADC output, the input of the subtraction unit connected to the information output of the signal restriction and expansion unit, the input of the second delay unit is connected to the second input of the subtraction unit, and the output of the second delay unit is connected to the second input om 5 1748287 6 adders, with the output of the third block of the replaceable low-pass filter, and the output of the holder connected to the second input of the control-> adder connected to the input of the DAC,>