KR830001249B1 - Beam Indexed Color Television Receiver - Google Patents

Abstract

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Description

Beam Indexed Color Television Receiver

1 is a connection diagram of an example of a video amp of a beam indexed color television receiver.

2 is a diagram for explaining phase distortion caused by characteristics of a video amp.

3 and 4 are each a schematic diagram of an example of the receiver of the present invention.

5 to 8 are connection diagrams of one example of each partial circuit.

9 to 12 are waveform diagrams for explaining the respective operations.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam indexed color television receiver, and more particularly to a circuit in which a phase of a gate pulse to gate a primary color signal of various colors is changed in accordance with the level of a signal applied to an image tube in a beam indexed color television receiver.

The beam index type color television receiver scans the fluorescent planes of red, green and blue color phosphor stripes in which a single beam is sequentially arranged in the horizontal scanning direction, and the index phosphor stripe arranged in the horizontal scanning direction on the inner surface of the fluorescent plane. The color is changed by the index signal obtained by scanning, and the electron beam is the red primary color signal when scanning the red color phosphor stripe, the green primary color signal when scanning the green color phosphor stripe, and the blue primary color when scanning the blue color phosphor stripe. As a signal, density modulation is performed respectively.

However, in such a beam index type color television receiver, the color of the reproduction image changes due to the change of the dice on the color phosphor stripe of the electron beam in the receiving tube due to the fixed brightness and chromaticity, mainly due to the characteristics of the video amp. There is a disadvantage in that the luminance or chromaticity decreases relatively. This phenomenon is particularly noticeable when the beam current is increased by adjusting the screen volume, color volume, or bright volume.

That is, as shown in FIG. 1, the red, green, and blue primary color signals E _R , E _0, and E _G are supplied to the gate circuits 70R, 70G, and 70B, and are sequentially twisted by 120 ° of the phase pulse P. _The gate signal is sequentially gated by _R , P _G and P _B and the switched primary color signal is applied to the first grid 11 of the water pipe 10 through the video amp 80, but the video amp 80 For example, the load resistor R _L , the collector of the transistor 81, the emitter, the resistor 83, and the emitter collector of the transistor 83 are connected in series, and the collector of the transistor 81 is connected to the grid 11. Connected, the primary color signal switched to the base of the transistor 83 is applied, a floating capacitor C _S exists between the collector, that is, the grid 11 and the ground of the transistor 81, the transistor 83 base potential rises the potential of the grid 11 of the time constant determined by the load resistance R _L C _S and the stray capacitance It is ever rises to.

Thus, for example, when the index phosphor stripe, I _N is formed in three ratios for two sets of the color phosphor stripes R, G, and B of red, green, and blue, as shown in FIG. In the case of reproduction of the signal, the signal applied to the grid 11 is displayed as G ₁ of 2 degrees when the level of the primary color signal E _G is low, and is displayed as G ₂ when the level of the primary color signal E _G is medium. When the level of signal E _G is large, G ₃ is displayed.

This invention is intended to eliminate such inconveniences with a simple configuration.

According to the present invention, the timing of the color switching, that is, the phase of the gate pulse to gate the primary color signal of each color can be changed according to the level of the signal given to the receiving tube. In other words, as the level of the signal increases, the phase of the gate pulse is advanced.

3 is an example of the receiver of the present invention, and reference numeral 10 denotes a beam index color water pipe, and a photodetector 20 is provided outside the funnel portion, and an output signal of the photodetector 20 is An index signal of a frequency which is supplied to the bandpass filter 30 and determined by the ping of the index phosphor stripe comes out and is supplied to the PLL circuit 40.

In the PLL circuit 40, the index signal from the band pass filter 30 is supplied to the phase comparator 41, and the output pulse of the voltage controlled oscillator 42 is supplied to the divider 43 to divide the divided pulse. So-called, supplied to the phase comparator 41, the output voltage of the phase comparator 41 is supplied to the oscillator 42 through the low pass filter 44, the so-called determined by the oscillator 42 is a pair of pitch of color phosphor stripes A pulse P ₀ of three times the trillion frequency is obtained.

In this example, the output pulse P ₀ of the oscillator 42 of the PLL circuit 40 is supplied to the variable phase shifter 50, and the red, green, and blue primary color signals E _R , E _G, and E _B are controlled. The control signal is supplied to the signal generator 90, which is supplied to the variable phase shifter 50 as an abnormal amount of control signal, and the abnormal pulse P _S comes out from the variable phase shifter 50.

Then, the output pulse P _S of the variable phase shifter 50 is supplied to the gate pulse generator 60 serving as a ring counter to control the primary, red, green, and blue primary color signals in a state regulated by the mode set pulse P _MS . The gate pulses P _R , P _G and P _B of the phase are obtained, and the gate pulses P _R , P _G and P _B are supplied to the gate circuits 70R, 70G and 70B, and the red, green and blue primary color signals are obtained. E _R , E _G and E _B are sequentially gated, and the switched primary color signal is supplied to the first grid 11, for example, through the video amp 80 through the video light 10.

Here, the control signal generator 90 is commonly connected to emitters of the transistors 91, 92 and 93, as shown in FIG. 5, for example, to the primary colors of the transistors 91, 92 and 93. The signals E _R , E _G and E _B are fed so that at the junction of the emitter the highest level of the primary colors signals E _R , E _G and B _{B as shown} in FIG. And one of 93 is turned on, and the other two are turned off, and the maximum voltage E _M is supplied to the transistor 94 to be inverted and can exit through the transistor 95.

In the variable phase shifter 50, for example, as shown in FIG. 6, the constant current source 51 and the collector-emitter of the transistor 52 are connected in series, so that the condenser (e.g. 53 is connected, and the output pulse P _O of the oscillator 42 of the PLL circuit 40 is supplied to the base of the transistor 52, and the control signal generator 90 controls the constant current source 51 of the constant current source 51. The constant current I _A is controlled so that the terminal voltage E ₁ of the capacitor 53 is supplied to the waveform shaping circuit 54 so that the output pulse P _S comes out of the circuit 54.

Therefore, as shown in FIG. 10, when the output pulse P _O of the oscillator 42 is turned on at " 1 ", the transistor 52 is turned on, the voltage E ₁ is at the ground potential as indicated by the arrow at the output pulse P ₀ at " When the transistor 52 is turned off from 1 " to " 0 ", the capacitor 53 is charged by the current I _A of the constant current source 51, so that the voltage E ₁ rises with a certain slope. And an output pulse P _S is the threshold level V ₀ is more than "0" when the voltage E _1, the waveform shaping circuit 54 is such that the "1" to the time equal to or less than the threshold level V _0, Therefore, the output stock of a pulse P _S Is delayed with respect to the arrival of the output pulse P _O of the oscillator 42, and the rising part of the output pulse P _S coincides with the rising part of the output pulse P _O of the oscillator 42.

The gate pulses P _R , P _G and P _B from the gate pulse generator 60 are inverted by the arrival of the output pulse P _S of the variable 50. At this time, the larger the maximum voltage E _M , the larger the current I _A of the constant current source 51. Therefore, the larger the maximum voltage E _M , the larger the slope of the voltage E _1, the faster the timing of arrival indicated by the arrow of the output pulse P _S , and the faster the phases of the gate pulses P _R , P _G and P _B.

As the signal level increases as described above, the phases of the gate pulses P _R , P _G and P _B are advanced, so that the delay of the phase due to the characteristics of the video amp 80 shown in FIG. The dice on the color phosphor strip of the electron beam are uniform, so that the color does not change or the luminance or chromaticity decreases relatively.

Further, as shown in FIG. 10, the output pulse P _N of the frequency divider 43 of the P _LL circuit 40 is inverted at the rising point of the output pulse P ₀ of the oscillator 42, and thus the impact of the frequency division pulse P _N. The duty factor is always 50% and its phase is not affected by the phase change of the output pulse P _S of the variable phase shifter 50.

4 is another example of the receiver of the present invention, when the voltage-controlled oscillator 42 itself of the PLL circuit 40 has an abnormal function so that a pulse P _S transferred directly from the oscillator 42 can be obtained. to be.

The voltage controlled oscillator is generally composed of an emitter coupled multivibrator, as in FIG. 7, that is, a capacitor 103 between the emitters of the transistors 101 and 102 is connected to the transistors 101 and 102. Constant current sources 104 and 105 are connected to the emitter of the < RTI ID = 0.0 > and < / RTI > load resistors R are connected to the collectors of the transistors 101 and 102, respectively. ) And the emitters of transistors 106 and 107 are connected to the bases of transistors 1 and 102.

Here, if the power supply voltage is Vcc, the forward drop voltage between the base emitters of the transistors 101 and 102 is V _BE , the capacity of the capacitor 103 is C, and the currents of the constant current sources 104 and 105 are I, respectively. Emitter potentials V _E1 and V _E2 of transistors 101 and 102 and collector potentials V _C1 and V _C2 of transistors 101 and 102 change as shown in FIG.

In other words, when the transistor 101 is turned on and the transistor 102 is turned off, the emitter potential V _E1 of the transistor 101 is V _CC -2V _BE , and the emitter potential V _E2 of the transistor 102 is V _CC -2V _BE + 2IR, and the capacitor 103 is charged with a voltage of 2 I.R at the polarity of the figure. From this point, a current of 2 I flows in the transistor 101, and the capacitor 103 of the transistor 101 A current of I flows from the emitter in the direction of the emitter of the transistor 102 to decrease to the slope at which the emitter potential V _E2 of the transistor 102 is determined to be 1 / C. Thus, when the terminal voltage of the capacitor 103 becomes 2I.R in reverse polarity with the polarity of the figure, the transistor 102 is turned on to become the positive feedback loop of the transistors 102, 107 and 101 so that the transistor 101 is turned off. The state is reversed. After the state reverses, it does the opposite.

Therefore, the oscillation frequency is set to 1 / C, so that the current I of the constant current sources 104 and 105 is changed, so that the oscillation frequency is changed.

On the other hand, the voltage controlled oscillator 42 in the example of FIG. 4 has transistors 114 and 115 connected in series with the transistors 101 and 102, for example in FIG. The emitters of 114 and 115 are commonly connected and a constant current source 118 is connected to its connection point, and the current 2I of the constant current source 118 is changed at the voltage from the low pass filter 44, as described above. As the oscillation frequency is changed as well, the maximum voltage E _M is applied between the bases of the transistors 114 and 115, and according to the magnitude of this voltage E _M.

Therefore, also in this example, as shown in FIG. 12, the phases of the gate pulses P _R , P _G, and P _G are reversed, and the dice for the color phosphor stripe of the electron beam are blown to the signal level as in the example of FIG. It becomes constant.

In this example also, as shown in FIG. 12, the output pulse P _N of the frequency divider 43 is inverted at the rising point of the output pulse P _S of the oscillator 42. Therefore, the duty factor of the frequency division pulse P _N is It is always 50% and its phase is not affected by the phase change of the output pulse P _S of the oscillator 42.

The above is not limited to the output pulse of the voltage controlled oscillator 42 of the PLL circuit 40, but may be the index signal from the bandpass filter 30 or the output pulse of the divider 43 of the PLL circuit 40. .

Thus, according to this invention, the change of the hue and the relative fall of the brightness | luminance or chromaticity resulting from the characteristic of a video amp can be avoided by a simple structure.

Claims (1)

Light having a single electron beam and having a primary color phosphor strip and an index stripe arranged in sequence, each of which is provided with a panel portion of the water tube to detect light from the index stripe. The detector 20, index signal processing circuits 30 and 40 for processing the output of the photodetector to generate a switching signal of the primary color signal, and a gate signal generating circuit for generating the gate pulse of the primary color signal based on the signal ( 60, a beam index provided with gate circuits 70R, 70G, 70B for gated each primary color signal in a different phase by this output, and a circuit 80 for supplying this output to a control electrode of the cathode ray tube. In the type color television receiver, the voltage controlled oscillator 42 is connected to the variable phase shifter 50 and the control signal generator 90 is connected to the variable phase shifter 50 to output the control signal generator. And a beam indexed color television receiver that compensates for phase delay in a high luminance signal by controlling the variable phase shifter and the voltage oscillator.

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