JPS6124877B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a beam index color television receiver.

In such a color television receiver, three primary color phosphors R, G, and B are repeatedly arranged on the inner surface of the face plate of the picture tube as shown in FIG. A first index element 2 consisting of a short-lasting phosphor is arranged repeatedly in a fixed relationship, and its end, in particular, precedes the phosphor and the first index element with respect to the horizontal scanning of the electron beam. When a second index element 3 is provided at a location with a period different from that of the first index element (1/3 in frequency) and the electron beam emitted from the single electron gun is swept, an index signal obtained from the index element is used. An electron beam based on each color signal impacts a predetermined phosphor.

Such a color television receiver is described, for example, in Japanese Patent Publication No. 39-5277, but in the process of converting the signal obtained from the first index element into the repetition frequency of the phosphor, all the signals are sinusoidal waves. However, the configuration proposed there is actually difficult to operate.

For this reason, the present applicant previously filed a patent application filed in 1973 for a beam index type color television receiver in which the above process is handled in the form of pulses.
Although it has already been proposed in No. 143873, the present invention is a further improvement thereof. Therefore, in the following, this prior art will first be explained.

In FIG. 1, reference numeral 4 denotes a picture tube having a structure similar to that shown in FIG. A photo multiplier 5 for conversion is installed. 6 is connected to the photo multiplier 5 and 2
It is an index signal separation means comprising lines 7 and 8 branched into two lines, and first and second bandpass filters 9 and 10 provided on each line, and the first bandpass filter 9 is a phosphor. If the double repetition frequency is f _t , then the frequency is selected to be 3/2 f _t (the frequency of the signal obtained from the first index element), and the second bandpass filter 10 is selected to be f _t /2. There is. Reference numerals 11 and 12 denote first and second comparators that convert the index signal separated by the separation means 6 into pulses, and specifically, convert them into TTL (transistor, transistor, logic) level pulses. 1
3 is a D flip-flop, and its T terminal (timing signal input terminal) receives the run impulse signal from the second comparator 12 [see Figure 2 C].
is applied, the signal shown in FIG. 2E is supplied to the D terminal (signal input terminal to be delayed), and the pulse shown in FIG. 2 is output. The pulse signal E inputted to the D terminal is formed by delaying the horizontal synchronizing pulse (FIG. 2 D) by monostable multivibrators 14 and 15 for a certain period of time. Since the D flip-flop 13 generates an output in response to a timing pulse (in this case, a run impulse signal) that comes in after the rise of the pulse signal H input to the D terminal, the run impulse signal H in FIG. Among these, the pulse rises due to the second pulse and falls due to the run impulse signal input after the fall time of the pulse signal E input to the D terminal, resulting in a pulse as shown in FIG. This output signal is delayed by delay circuits 16 and 17 consisting of monostable multivibrators as shown in FIG. 2, and is converted into a very wide pulse. 18 connects the delay circuit 17 to the D terminal.
This is a D flip-flop which is supplied with the pulse signal G from the first comparator 11, and receives the first index pulse signal [FIG. 2B] from the first comparator 11 at its T terminal, and outputs the pulse of FIG. 2H. 19 is means for extracting the first index pulse signal using the output chip of the D flip-flop 18;
In the illustrated example, it is composed of a NAND circuit.
Therefore, the signal shown in FIG. 2 is given as the output of the extraction means 19 shown in FIG. 20 indicates that the signal from the extraction means 19 has a frequency of 3/2f _{t .}
21 and 22 are D flip-flops that together with a NAND circuit 23 and an inverter 24 constitute a frequency divider. Q output of the D flip-flop 21 [second
(see Figure N) is applied to the NAND circuit 25, where it is NANDed with the separately applied extracted first index pulse signal R. Therefore, the NAND circuit 25
Figure 2 is obtained as the output. The Q output (see FIG. 2) of the other D flip-flop 22 constituting the frequency divider is supplied to the NAND circuit 26.
The extracted first index pulse signal as another input to the NAND circuit 26 is a pulse train signal obtained by inverting the signal shown in FIG. Therefore, the output shown in FIG. 2 is obtained as the output of the NAND circuit 26. The outputs of these NAND circuits 25 and 26 are further NANDed by the NAND circuit 31 to obtain the final output of the frequency conversion circuit 20 as shown in FIG. As can be seen from the fact that this converted signal corresponds to B of the three primary color phosphors, it is exactly the repetition frequency f _t of the three primary color phosphors. The pulse signal with the frequency f _t obtained in this way is converted into a sine wave signal through the bandpass amplifier circuit 28, mixed with a separately provided color signal in the mixer 29, and further mixed with the luminance Y signal and the adder 30. is guided to the grid electrode of the picture tube 4, which is added at . still,
The signal of frequency f _t shown in Figure 2 (F) (later converted into a sine wave) contains color information by successively changing its phase in accordance with the color signal. It goes without saying that there should be no variation in the phase of the reference signal shown in FIG. 2F before it is mixed with the color signal. However, in beam index color television receivers. In very dark areas of the image, the electron beam is extremely weak, so either no index signal is obtained from the index element, or even if it is obtained, the amount of signal is insufficient, resulting in a missing part in the index pulse signal shown in Figure 3 (b). It turns out. This pulse loss also appears in the extracted index pulse signal shown in FIG. 3, and changes the phase of the output pulse of the frequency conversion circuit 20. That is, if there is a missing part in the index pulse signal A as shown in FIG. The phase of the pulses differs in the portions corresponding to the missing portions of the index pulse signal, as shown in FIG.
The output of 0 also becomes as shown in Figure 3 (F). It is needless to say that even if the color signal beam control is performed using the signals shown in FIG.

In view of these points, the present invention provides a beam index type color television that is devised so that a normal pulse train signal can be generated from the frequency converter even if the beam index pulse signal is missing in a very dark screen. This project proposes a radio receiver.

FIG. 4 shows a schematic configuration of a beam index type color television receiver of the present invention, and the same parts as in FIG. 1 are given the same symbols for convenience of explanation. Reference numeral 32 denotes a reference signal oscillator which generates a frequency pulse of 3/ _2ft , and its start of operation is controlled by the output chip of the D flip-flop 18. 33 is a phase comparator that performs a phase comparison between the output of the reference signal oscillator 32 and the extracted index pulse signal, and 34 is an integrating circuit that converts the comparison output into DC. 35 is a voltage controlled oscillator which essentially generates a pulse with a frequency of 3/ _2ft and whose oscillation is controlled by the output of the phase comparator 33, and like the reference signal oscillator 32,
It is operated by the output chip of the D flip-flop 18. The output of the voltage controlled oscillator 35 is applied to the frequency converter 20 described in FIG. 1 and converted into pulses at the triplet frequency f _t . As mentioned above, in the present invention, the oscillation pulse of the voltage controlled oscillator 35 that generates continuous pulses is frequency-converted and used to control the color signal. Even if there is a omission as shown in Figure 3 B, the third
Malfunctions such as those described in the figures do not occur. The reason why the voltage controlled oscillator 35 is controlled by the phase comparison output of the index pulse signal and the output of the reference signal oscillator 32 is because the scanning speed of the electron beam is not uniform over the entire screen but at each location. This is because the pulse train applied to the frequency converter 20 must not have a fixed phase and must incorporate changes in the scanning speed of the electron beam. Since li matches the scanning speed of the electron beam, if this signal is used to control the voltage controlled oscillator 35, the signal used to control the color signal will match the actual scanning of the electron beam. It is from. In addition, the reference signal oscillator 3
The reason why the operation of the voltage controlled oscillator 2 and the voltage controlled oscillator 35 is started by the output chip of the D flip-flop 18 is to ensure that the pulse train input to the frequency converter 20 starts at a predetermined phase, and the output of the frequency converter 20 starts at a predetermined phase. This is to make the color match a predetermined color (for example, blue B) as shown in FIG. 2F.

According to the present invention, in addition to the effects of the invention proposed in Japanese Patent Application No. 51-143873, there is no malfunction in color signal control even when the index pulse signal is missing in a dark part of the image. This has the effect of not causing

Further, since the output of the reference signal oscillator and the index signal are compared in phase and the voltage-controlled oscillator is controlled by the comparison output, the accuracy of the index signal obtained from the voltage-controlled oscillator is improved. Furthermore, in the present invention, the oscillation operation of the reference signal oscillator and the voltage controlled oscillator is started in response to the output of the D flip-flop, so the oscillation start time is fixed, and thereby the index signal obtained from the voltage controlled oscillator is This also has the effect of increasing stability.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing a prior art beam index type color television receiver, and FIGS. 2 and 3 are explanatory diagrams thereof. FIG. 4 is a block circuit diagram of a beam index type color television receiver embodying the present invention. R, G, B... Three primary color phosphors, 2... First index element, 3... Second index element, 4
... Picture tube, 5 ... Photomultiplier (detection means), 6 ... Separation means, 9, 10 ... Comparator (pulsing means), 13 ... D flip-flop (pulse synchronized with specific pulse of run-in signal) means for creating), 14, 15, 16, 17
... Monostable multivibrator, 18 ... D flip-flop, 19 ... Index pulse extraction means, 20 ... Frequency converter, 28 ... Bandpass amplifier, 29 ... Mixing circuit, 32 ... Reference signal oscillator, 33 ... Phase comparator, 35 ... Voltage controlled oscillator.

Claims (1)

[Claims] 1 Three primary color phosphors of red, green, and blue repeatedly arranged in a stripe pattern, a first index element repeatedly arranged in a stripe pattern in regular relationship with these phosphors, and horizontal scanning of an electron beam. On the other hand, electrons emitted by a single electron gun are applied to a surface consisting of the phosphor and a second index element, which is provided in small numbers with a period different from that of the first index element, at a location preceding the first index element. An electron beam based on a color signal is controlled to impact a predetermined phosphor based on an index signal obtained from the index element when the beam is swept, wherein means for detecting the signal obtained from the index element; means for separating the output signal of the detection means into a first index signal obtained by the first index element and a run-in signal obtained by the second index element; means for pulsing each of the signals; and a run-in signal from the separation means. means for creating a pulse synchronized with a particular pulse of the signal; means for delaying said pulse; a D flip-flop to which the pulse from said delay means and a first index pulse signal from said separating means are applied; means for extracting the first index pulse signal using the output of the D flip-flop; a reference signal oscillator that starts oscillation upon receiving the output of the D flip-flop; and a means for extracting the first index pulse signal using the output of the D flip-flop; a phase comparator that performs phase comparison with a pulse signal; a voltage-controlled pulse oscillator that starts oscillation upon receiving the output of the D flip-flop and is controlled by the output of the phase comparator; and an output pulse of the voltage-controlled pulse oscillator. a circuit for converting the frequency into a pulse signal of the repetition frequency of the phosphor, and a circuit for converting the output of the frequency conversion circuit into a sine wave signal;
A beam index type color television receiver comprising a circuit for mixing the sine wave signal and a color signal.