JPS6016085A - Character pattern signal superimposition device - Google Patents

Abstract

PURPOSE:To realize an absolutely correct color ratio by using a decoder circuit selecting a special output for the 2nd control circuit in response to the combination of an inputted superimposing video information signal. CONSTITUTION:The 2nd control circuit applying superimposing video information signals R', G', B' to an output terminal of a transistor 17 of the output stage of an amplifier circuit 22 is used for a decoder 24 selecting a special output in response to the combination of the superimposing video information signals R', G' and B' to be inputted. One outut is selected through the combination of the three inputs R', G' and B' and the color ratio of a ratio adjusting circuit 26 is decided absolutely to the three outputs, then the absolutely correct color ratio is realized to an optional combination of the signals R', G' and B' so as to obtain an accurate composite video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a text/graphic signal superimposition device, and more specifically, the present invention relates to a text/graphic signal superimposition device that mixes a chroma demodulated signal, which is an analog signal in a television receiver, and a text/graphic information signal, which is a digital signal input from the outside. This invention relates to a two-system signal mixing device for analog and digital signals.

Conventionally, as this type of character/figure signal superimposition device, for example, Japanese Patent Application No. 57-169151 filed by the present applicant;
The name of the invention is ``Character/Graphic Signal Superimposition Device.''

As shown in FIG. 1, the character/figure signal superimposition device described above is
The input stage transistor (1) is configured such that the amplification factor is 1 with at least two transistors (1, 2).
an amplifier circuit (3) that inputs a television image signal (for example, R-Y) to the base of the television image signal (R-Y);
The superimposition video information signal (digital signal) to be superimposed on the superimposition video information signal (digital signal).

A cutoff signal (R'10B'10G') that is generated based on /, c/, and cuts off a portion of the television image signal that corresponds to the superimposition video information signal is sent to the intensifier. A second control circuit (
6), and the television image signal (R-Y) and the superimposition video information signal (
R', G', B') to obtain a composite signal, and the output terminal (5) of the transistor (2) in the output stage of the second control circuit (6) and the amplifier circuit. A ratio adjustment circuit (7) for setting the color ratio of the video signal for superimposition is provided between the two, and the color ratio of the composite signal is adjusted by adjusting the color ratio of the television image signal (
This is made to match the following equation (11, (21, <31, f4)).

Ey = 0.30ER+0.59EC+0.11EB
...(1) ER-EY=0.70ER-0,59E
C-0,11EB...(2)EB Ey= 0.3
0ER-0,59EC+〇,89EB...(3)E
G Ey= 0.30ER+〇, 41EG O, 11E
B...(4) As a result, if the color ratio adjustment circuit (7) is not provided, a pulse signal with a constant amplitude (V) as shown by the two-dot chain line in Fig. 2 will be obtained, whereas the pulse signal as shown by the solid line will be Thus, ', G', and B' are synthesized as a signal with the correct color ratio determined by the television system. Therefore, the output signal of this device is input to a color encoder to generate the correct color consisting of two systems of analog and digital signals. A composite video signal having a ratio can be obtained, making it easier to support system expansion.

However, in the circuit shown in Fig. 1, when any one or all of the R', G', and B' multiplied signals are input to the second control circuit 6, the resistors 8, 9, and , cyan, magenta, pre-me R, G.

It was found that the absolutely correct color defined by B' was not reproduced.

This is because the two resistors 9 and 10.11 are connected in parallel due to the input of the two combinations of R', G', and B', and their combined resistance value becomes smaller with respect to the collector resistor 8, resulting in deviation from the original correct color ratio. , it is analyzed that an absolutely correct composite color (yellow, cyan or magenta) is not achieved.

(Objective of the Invention) Therefore, the present invention provides R', G',
It is an object of the present invention to provide a character/graphic signal superimposition device that can realize an absolutely correct color ratio for any combination input of B'.

(Summary of the Invention) Therefore, in the present invention, a second control circuit is shown in FIG. 1, which supplies the superimposition video information signal to the output terminal of the transistor in the output stage of the amplifier circuit. An inverter 1 receives the /, c/, and B/ times signals individually and supplies them to the output terminal 5 individually.
2, 13, and 14, the basic feature is that a decoder circuit is used to select a specific output according to the combination of input video information signals for superimposition.

One output, for example, the output corresponding to yellow, is selected by the combination of the three input ', G', and B' signals, and the color ratio of the ratio adjustment circuit is absolutely determined for this yellow output, so k' , G', and B', and a more accurate composite video signal can be obtained than in the conventional example.

Hereinafter, the present invention will be specifically explained with reference to Examples.

(Example) The basic circuit of the superimposing device of the embodiment is shown in FIG.

In FIG. 3, the basic circuit 15 connects a PNP) transistor 16 and an NPN) transistor 17 to resistors 18, 1
9, 20, and 21, an amplifier circuit 22 is connected in a complementary manner so that the amplification factor is 1, and is supplied with a voltage of 10B1;
Digital signals such as text characters, R signals, G signals, and B signals are input to the NPN output stage of the amplifier circuit 22.
A decoder circuit 24 as a control circuit of the first control circuit and the second control circuit connected to the base of the +- transistor 17, and between the decoder circuit 24 as the second control circuit and the output terminal 25 of the amplifier circuit 22. Connected ratio adjustment circuit 26
A television image signal (for example, R-Y
) is input. Note that the amplifier circuit 22 may be configured using an NPN transistor in the input stage and a PNP l-transistor in the output stage.

The first control circuit 23 includes open collector type inverters 27, 28, 29, 30, 31 and a resistor 32,33, and is supplied with a voltage of 10B2 via the resistor 32,33. Inverters 27, 28° and 29 each have a
signal, G' signal, and B' signal are input, and the inverter 27
, 28 and 29 are wired-ORed and input to the inverter 30. The output of the inverter 30 is input to the inverter 31-, and the output of the inverter 31 is input to the base of the transistor 17 in the output stage of the amplifier circuit 22. That is, at the base of the transistor 17,
A signal of R+G'10B is input as a logical formula. Therefore, in the basic circuit 15, if at least one of the text character signals becomes 'H' level, the first control circuit 23 turns off the NPN) transistor 17, and the color difference signal, for example, the (RY) signal is turned off. NPN of that text character part)
The input to the transistor 17 is cut off, and the potential at the output terminal 25 of the amplifier circuit 22 increases toward the 10B voltage.

The decoder circuit 24 as the second control circuit is operated by three people.
It is a decoder circuit with 8 outputs, and the G' signal, k' signal, and B' signal are input to input terminals 34, 35, and 36, respectively, and the output terminal 37 is input according to the combination of input signals R', G', and B'.
, 38, 39, 40, 41, 42°43. Table 1 shows the input/output relationship of the decoder circuit 24 and the output color correspondence relationship. B', G',
Logic "1" or "0" of B' corresponds to a high level ("H") or a low level (rLJ) in voltage level, respectively.

Table 1: The ratio adjustment circuit 26 that determines the color ratio is connected to each output terminal 37, 38, 39°40.41,
Resistors 44 and 45 are connected between 42 and 43 and the output terminal 25 of the amplifier circuit 22, respectively.

It consists of 46.47, 48, 49.50. Each resistor 44.
Basically, the resistance ratio between the resistance values of 45, 46, 47, 48, and 49.50 and the resistance value of the collector resistor 20 of the output stage transistor 17 of the amplifier circuit 22 is as follows.
), more specifically, based on Table 2 below.

In setting Table 2, the DC component of the television image signal input to the input stage transistor 16 of the amplifier circuit 22, the characteristics of the output stage transistor 17, the magnitude of the B1 voltage, and the output of the pond water device are used. The characteristics of the IC circuit are also taken into account. To simplify it, the voltage between the pedestal level and +B1 level of the television image signal is
For example, if the ratio of the divided voltage divided by the resistance ratio of the collector resistor 20 and each resistor 44 to 50 is (RY), then 0
゜0.11, -0.7, -0.59, +0.59,
+0.7.

-0,11. Here, the - (minus) sign indicates the case where the value is lower than the pedestal level. For example, if 10B1=12 (V), the pedestal level is 6.
V, and in the case of "Blue" in Table 2, it is Noy%Z〆); 777/11 Dadi V Podo Zgu (Z夛孝目 ? 衾P し夛) 9汐Z7 Television Station When the image signal is (RY), it is 0.66 (V) lower than the pedestal level, that is, 5.34 (V) from the ground level. In this case, if the resistance value of the collector resistor 20 is Rc and the resistance value of the resistor 50 of the output terminal 43 is 5o, then Rs
From the formula: o/(Rc+R50)=5.34/12, R5° is determined.

Note that it is preferable that the Yamakawa resistor 44 be a variable resistor.

The advantage is that if there is a carrier leak and the white becomes reddish or bluish or the brightness is too strong, you can make fine adjustments later to prevent this. Also, the resistance outside the white breath is 45, 46, 47°48.49.
50 can also basically be made into a variable resistor. However, considering the cost and the complexity of adjustment when flowing into the line, it is desirable to use a fixed resistor.

The color difference signal (which is the chroma demodulation output of a television receiver)
An example of the R', G', and B' times signal superimposition operation of digital signals will be explained. Now, l('=[J, G'=
It is assumed that a signal "rxJ, B'=ro" is input to the basic circuit 15. The output of the first control circuit 23 is it+c+
B- "Turn off the transistor 17 when the signal becomes OJ and this signal is input.

The voltage at the output terminal 25 tends to rise toward the 10B1 voltage. On the other hand, in the decoder circuit 24, R'G'B'=rl
Decode lOJ, select only the output terminal 38 (yellow), and drop the output terminal 38 to rLJ. The voltage that is about to rise towards the 10B1 voltage is divided by the resistance ratio of the collector resistor 20 and the resistor 45, and the rise is stopped at the voltage corresponding to the yellow color ratio of 0.11 shown in Table 2. stay. The color signal matching this yellow color ratio is superimposed only on the digital signal input section of the (RY) signal amplified with an amplification factor of 1, and is output as a superimposed signal (RY)'.

The same goes for the other colors, white, cyan, green, magenta, red, and blue.The KGB color signal is decoded, and each of the decoded color signals is combined with a cutoff signal to cut off the television image signal using the transistor 17. The inverted and amplified signal is connected to each of the resistors 44 and 46.

47, 48, 49, and 50 to distribute and output the color ratio level corresponding to the television image signal.

In the superimposing device according to the present invention, the chroma IC produces color difference signals, i.e., (IIY) signal, (G-Y) signal, (B-Y
), if the demodulation circuit outputs a signal, the fourth
As shown more specifically in the figure, in addition to the (RY) signal,
The basic circuit 15 similar to that shown in FIG. 3 above is also connected to the (B-Y) signal and the Y signal. It is preferable to use an IC as the decoder circuit 24, and in this case, 4 people/1
A 6-output decoder IC, such as Text Instruments product number 74159, can be used. In this case, one input (D input) is grounded and not used. IC
24 is supplied with a voltage of 10B2 as a power source. 1 signal to B input of pin 14, G signal to input to pin 15, 1
The B signal is input to the C input of the 3rd pin. Each resistor of the ratio adjustment circuit 26 of the basic circuit 15 into which the television image signal (B-Y) is input and the basic circuit 1 in which the signal Y is manually input.
The resistance value of each resistor of the ratio adjustment circuit 26" of No. 5 is as shown in No. 3 above.
) is selected based on equation (1) so as to match the color ratio shown in Table 2.

Therefore, the (R-Y)' signal, the (B-Y) signal and the Y signal output from the character/graphic signal superimposition device shown in FIG. 4 are input to a color encoder (not shown) to ensure the absolute correct color. It is possible to obtain a composite video signal in which a text character signal, etc. is superimposed at a certain ratio, and when this composite video signal is reproduced, correct colors can be reproduced even with the composite color of the character signal, etc.

In the above embodiment, the circuit of the character/figure signal superimposition device for three systems of (RY) signal, (B-Y) signal, and Y signal is shown for input to the color encoder, but (G -Y) signal is not recombined, even if the color encoder is a four-man power system, the (G-Y) signal is
4) It may be formed based on the formula.

Furthermore, in the case where the chroma IC in the television receiver is a demodulation circuit that outputs color signals of three primary colors, that is, an R signal, a G signal, and a B signal, the present invention provides a demodulation circuit that corresponds to each color signal. Three basic circuits 15 may be provided.

(Effects) As is clear from the detailed description above, the present invention has the following effects:
By improving the conventional character/graphic signal superimposing device equipped with a ratio adjustment circuit that supplies R, G, and B individual color signals, R, G,
By using a decoder circuit that selects a specific output corresponding to each color according to the combination of individual signals of B, the color ratio is made to absolutely match the color ratio corresponding to each color of the television image signal. When the color ratio of a video signal for superimposition, which is a digital signal system, absolutely matches a certain television image signal, the output signal of the character/graphic signal superimposition device according to the present invention is inputted to a color encoder to convert the analog and digital signals. It is possible to obtain a composite video signal having a correct color ratio consisting of systematic signals, and there is an effect that the composite color can also be reproduced in the correct color upon reproduction.

[Brief explanation of the drawing]

Fig. 1 is a basic circuit diagram of a conventional example, Fig. 2 is an explanatory diagram of waveforms output from the basic circuit, and Fig. 3 is a character/character diagram according to the present invention.
FIG. 4 is a basic circuit diagram of an embodiment of a graphic signal superimposing device. FIG. 4 is an overall circuit diagram of a specific example of a character/graphic signal superimposing device according to the present invention. 15...Basic circuit, 16...PNP transistor,
17...NPN) transistor, 18, 19, 20° 21... resistor, 22... amplifier circuit, 23... first
control circuit, 24...decoder circuit as a second control circuit, 25...output terminal, 26...ratio adjustment circuit, 44-50...resistors. Patent applicant Sharp Co., Ltd. Agent Masu Aoyama Hajime and 2 others

Claims (1)

[Claims] (1) An amplifier circuit configured to have an amplification factor of 1 using at least two transistors, which inputs the television image signal to a transistor base in the input stage, and an amplifier circuit for superimposing the television image signal on the television image signal. a first control circuit that inputs a cutoff signal generated based on the video information signal and that cuts off a portion of the television image signal corresponding to the video information signal for superimposition to the base of the transistor in the output stage of the amplifier circuit; and a second control circuit that supplies the superimposition video information signal to the output terminal of the transistor in the output stage of the amplifier circuit, and a second control circuit that supplies the superimposition video information signal to the output terminal of the transistor in the output stage of the amplifier circuit. A ratio adjustment circuit for setting the color ratio of the video signal for superimposition is provided between the output terminal and a composite signal of the television image signal and the video information signal for superimposition is obtained from the output terminal of the amplifier circuit. In the text/figure signal superimposition device in which the color ratio is made to match the color ratio of the television image signal, the second control circuit controls a specific output according to the combination of the superimposition video information signals manually inputted. A character/figure signal superimposition device characterized by being a decoder circuit for selecting.