SU1690220A1 - Device for correction of brightness signal and color discrimination signal - Google Patents

Abstract

The invention relates to a television technique. The purpose of the invention is to improve the accuracy of the correction. The device contains the first amplifier 1, the first switch 2, the second amplifier 3, the third amplifier 4, the second switch 5, the fourth amplifier 6, the first and second differentiating blocks 7 and 8, the pulse shaper 9, the clamping unit 10, the variable delay unit 11 and the amplifier 12. Into the device are connected in series the luminous transition signal determining unit 13, the signal determining unit 14 the difference in transition time, the second input of which is connected to the outputs of the pulse former 9, and the control signalformer 15, the second input which is input to the control signal, and an output connected to the control input 11 of the variable delay unit. The output of the latter is connected to the input of the fifth amplifier 12, and the input is combined with the input of the block 13 for determining the transient signal. Improving the accuracy of the correction is achieved by combining the transitions of the luminance signal and color for different durations of color transitions. 2 Il. Up CO with

Description

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Yu Yu

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FIG. one

The invention relates to a television technique and may be used in color television successors.

The purpose of the invention is to improve the accuracy of the correction.

FIG. Figure 1 shows a structural electrical circuit diagram for correcting the luminance signal and color-difference signals; in fig. 2 - signal plots showing the operation of the device.

The device for correctiveness of the luminance signal and color-difference signals contains the first amplifier 1, the first switch 2, the second amplifier 3, the third amplifier 4, the second switch 5, the fourth amplifier b, the first differentiating unit 7, the second differentiating unit 8, the pulse shaper 9, the unit 10 anchors, a variable delay unit 11, a fifth amplifier 12, a transient signal determination unit 13, a difference detection unit 14, a transition time difference, a control signal driver 15.

The device works as follows.

The color difference signals (RY) and (BY), which have transitions (Fig. 26), go to bpocks 7 and 8, to the first amplifier 1 and to the first input of the first key 2, and the color difference signal (BY) through the second amplifier 9 - at the first input of the second key 5. In the first and second differentiating units 7 and 8, the color difference signals are differentiated and detected. At the place of transitions, pulses (Fig. 2E5) of positive polarity are formed, the amplitudes of which are proportional to the steepness of the fronts of the color difference signals. These pulses pass through the pulse shaper 9, in the received signal (fig. 2d) the negative part is suppressed, after which the signal arrives at the pulse shaper 9. When the signal exceeds the threshold voltage UK. At the output of the pulse former 9, rectangular pulses are obtained (Fig. 2e), the duration of which corresponds to the duration of transitions in the UK level. The output signal from the imaging unit 9 of the pulses is fed to the second inputs (being control) of the first 1 and second 2 keys. In the absence of pulses (Fig. 2d), keys 2 and 5 are closed and color-difference signals are freely passed to the second and fourth amplifiers 3 and 4. In this case, the levels of color-difference signals are remembered by cascades of memory included in keys 1 and 2, respectively. In this case, capacitors are used as memory elements. In the wet-mening of the presence of pulsary (Fig. 2d) keys 2 and

5 is quickly disconnected and voltages are maintained at the inputs of amplifiers 1 and 3 that were immediately prior to switching. At the end of the transitions the first 2

and the second 5 keys are locked. At the outputs of amplifiers 4 and 6, signals are generated similar to the signal in FIG. 2g, thus, the color difference signals (R-Y) and (B-Y) have abbreviated transitions. The signal diagrams (Fig. 2c, d on the right) show that the differential component of the slow transition is small. Thus, the pulse shaper 9 produces a short pulse, resulting in a small effect on the color difference signal, i.e., transitions with a steepness approaching the limit of the system are corrected, while slower transitions remain unchanged. Slow gentle color transitions determined by the plot image do not change. Since color difference signals are delayed by time DI as a result of color transition correction, the luminance signal

should be delayed by the time t - t Nom + D1, where Gnome is the nominal delay time in the luminance channel. Compared with the minimum transient duration of the luminance signal of 15 ns, the transient time of the color difference signal is about five times longer, i.e. equals 8 not. It may vary depending on the color television signal. Therefore, a change in delay is necessary.

the brightness signal in accordance with the duration of color transitions, as well as the accuracy of matching the brightness and color transitions, as well as the accuracy of matching the brightness and color transitions was at least 40 ns.

The luminance signal (Fig. 2a) is fed to an anchor block 10 and after an anchor to the required level is fed to a block 13 of the signal of the transition of the transition and

The variable signal delay detection unit. The block of the signal of the transient transition can be performed similarly to the block 3 of the definition of the signal of the color transition. At the output of block 13 of the signal of the transient transition, a rectangular pulse is formed corresponding to the transient transition (Fig. 2h). The first and second inputs of the signal detection unit 14, the difference in transition times, receive pulses corresponding to the capacitive (Fig. 2h) and color (Fig. 2e) transitions. At the output of the signal detection unit 14 of different transition times, a signal is formed whose amplitude is proportional to the difference between the times of the capacitance and color transitions, for example, the time difference I I between the leading edge of the pulse of transition and the forward front of the inverse pulse of the color transition (FIG. 2e), i.e. The signal determining unit 14, transition time differences, is a time-to-voltage converter. From the output of the signal determining unit, the difference in the transition times is given to the signal at the first input of the driver 15 of the control signal. To the second input of the driver 15 of the control signal, a signal of manual adjustment Up is received. If the signal U is zero, then the output signal of the driver 15 of the control signal depends on the signal at its first input. At the output of the driver 15 of the control signal, a control (discrete) signal is formed that directly controls the delay of the luminous signal.

Claims (1)

Claims An apparatus for correcting a luminance signal and color difference signals comprising a first amplifier connected in series, whose input is an input of a color difference signal (R-Y), a first switch and a second amplifier whose output is a signal output (R-Y). and a third amplifier connected in series, whose input is an input of a color-amplifying signal (BY), a second key and a fourth amplifier whose output is an output of a color difference signal (B-Y), the first and second differentiating units whose inputs are connected respectively to the inputs the first and third amplifiers, and the outputs of the differentiating units are combined and connected via the pulse shaper to the second inputs of the first and second keys, the anchor block, the input of which is the input of the luminance signal, and the output connected to variable delay unit, and a fifth amplifier, the output of which is the output of a luminance signal, is characterized in that, in order to improve the accuracy of the correction, a successively connected luminous transition signal determination unit and a differential signal detection unit, the second input of which connected to the pulse generator outputs, and the driver of the control signal, the second output of which is an input for the control signal, and the output of the driver-control signal is connected to the control input variable variable block, the output of which is connected to the input of the fifth amplifier, and the input of the variable delay unit combined with the input of the luminous junction signal determining unit. but FIG g