SU1319320A1 - Device for correcting cross-distortions of brightness signal - Google Patents

Abstract

The invention relates to television and reduces distortion of the luminous signal. At the output of amplifier 1, the capacitive signal changes from zero to the value of UMBKC. If the signal value is less than Input 0, 1 imax, then the signal at the output of amplitude limiter 3 is zero. In this case, the luminance signal through the delay unit 6, the adder 5, the delay unit 7 and the adder 8 passes to the output unchanged, since the chroma signal distortions caused by the luminous signal do not exceed the permissible value. For large values of the amplified signal, the signal selected by filter 2 passes through amplitude limiter 3 and weighing amplifiers 4 and 9 to adders 5 and 8. Signs and abs. weight values. coefficients weighing amplifiers are such that at the outputs of adders 5 and 8 the spectral components close to the resonant frequency of filter 2 are attenuated. 3 il. Bbiwd with; o oo y Fy

Description

The invention relates to television technology and can be used as a part of color television sensors of the SECAM system.

The purpose of the invention is to reduce the distortion of the luminous signal.

FIG. Figure 1 shows the structural electrical circuit of the proposed device; in fig. 2 - amplitude-frequency characteristic (AFC); in fig. 3 - transient response (HRP) of the proposed device (a) and amplitude response of the amplitude limiter (b).

A device for correcting the distortion of the luminous signal (Fig. 1) contains amplifier 1, filter 2, amplitude limiter 3, first weighing amplifier 4, first adder 5, first delay unit 6, second delay unit 7, second adder 8 and second weighing amplifier 9 .

The device (Fig. 1) works as follows.

The input signal of amplifier 1 receives a loudspeaker signal with a span of LJ ,,. At the output of amplifier 1, the signal Uy can vary from zero (when transmitting a signal corresponding to the black level) to the maximum value corresponding to transmitting the signal corresponding to the white level (its standard value is 700 mV). If the value of U ,; less than mV 0.1 UMBKC (frequency response in Fig. 2), then the output signal of the amplitude limiter 3 is zero (Fig. 36). In this case, the luminance signal through block 6, the adder 5, block 7 and the adder 8 passes to the output without changes, since in this case the distortions of the chromaticity signal caused by the luminous signal do not exceed the permissible value. For large values of U ,, the signal extracted by filter 2 passes to the output of amplitude limiter 3. The extreme values of the output signal of amplitude limiter 3 correspond to the resonant frequency of filter 2 equal to 286 MHz (average frequency of the chromaticity subcarriers of the standard signal SECAM). The signs and absolute values of the weighting factors ei and 62 selected for the first 4 and second 9 weighing amplifiers are such that at the outputs of the first 5 and second 8 adders

spectral components close to the frequency o are attenuated. The component with the frequency fo at the output of the device is attenuated to 70 mV. For all values of U ,,, satisfying the condition of 70 mV. Jy 700 mV, the signal at the output of the first adder 5 on

0, the frequency fo is equal to (U ,, + 2Uo) / 2. The frequency response of the device (Fig. 2) corresponds to the value of mV. The transient response at the output of the first adder 5 is asymmetric in shape, with the difference that the positive outlier, as well as the height and width of the step before the outburst, is approximately two times smaller (due to the choice of the characteristics of the amplitude limiter 3). As a result of the second delay unit 7, a negative outburst appears in the lower portion of the transient response and the transient response has a symmetrical shape (Fig. 3A), the emission value is approximately half as large, and their symmetry additionally reduces the distortion of the signal .

Claims (1)

Invention Formula A device for correcting a crosstalk of a luminous signal containing a series-connected amplifier, a filter, an amplitude limiter, a first weighing amplifier and a first adder, the second input of which is connected to an output of 5 bodies through a first delay block, characterized in that, in order to reduce distortions pkostnogo signal, introduced the second weighing amplifier, the second delay unit and the second adder, the output of which is the output of the device, and the first and second inputs through the second weighting amplifier a second delay unit connected respectively to the outputs of the amplitude limiter and the first adder. / / IW 0.1 / FIG 2 but