JPH0250477B2 - - Google Patents

Description

TECHNICAL FIELD The present invention relates to a color encoder that generates a video signal from a color code signal input as a digital signal.

BACKGROUND OF THE INVENTION A color encoder, also called a color coder or a color plexer, has the function of combining three primary color signals of red, edge and blue into one signal within the frequency band of a television receiver.

An example of a conventional color encoder used in a video processor is shown in FIG.

1 is a matrix circuit that converts the three primary color signals R, G, and B of red, green, and blue input as analog signals into a luminance signal Y and color difference signals R-Y and B-Y (or I and Q). , the luminance signal and the color difference signal are respectively: Y=0.3R+0.59G+0.11B (1) R-Y=0.7R-0.59G-0.11B (2) B-Y=0.89B-0.3R-0.59G (3) It is expressed as I=0.6R−0.28G−0.32B (4) Q=0.21R−0.52G+0.31B (5). Whether R-Y and B-Y or I and Q are used as the color difference signals is a matter that is appropriately selected depending on the type of the subsequent system.

2 is a modulator that amplitude-modulates the first color subcarrier Sc ₁ of, for example, 3.58 Mc by the color difference signal R-Y (or I) from the matrix circuit 1; 3 is a modulator whose phase is 90 degrees different from the first color subcarrier; The second color subcarrier Sc2 is converted into the color difference signal B-Y (or Q) from the matrix circuit 1.
This is a modulator that modulates the amplitude by The first and second color subcarriers amplitude-modulated by modulators 2 and 3, respectively, are added in an adder circuit 4 to produce a color signal, and a burst signal is added thereto, and the burst signal is further added to this color signal. A synchronizing signal and a luminance signal Y from the matrix circuit 1 are added to the signal in an adder circuit 5 to obtain a video signal.

In place of such an analog color encoder, a digital color encoder has been proposed, for example, in Japanese Patent Publication No. 46-29284. In this conventional digital color encoder, each of the 3-bit color information or color code is AND-processed with the luminance signal from the character coder, and each output of the AND circuit is a "0" or "1" of the primary color signal RGB. ” By expressing
It can output color signals of eight colors including white and black.

Problems to be Solved by the Invention In the conventional color encoder disclosed in the above-mentioned Japanese Patent Publication No. 46-29284, only "0" or "1" of the primary color signal RGB is controlled.
8 obtained by combining bit color codes
The color was the maximum number of colors. That is, in the prior art, the number of colors that can be generated is small, and the encoder is insufficient, especially as a color encoder that must display a wide variety of characters, such as in video game devices, television game devices, and the like.

Therefore, the main object of the present invention is to provide a color encoder that can generate a larger number of colors.

Means for Solving the Problems To put it simply, the present invention is a color encoder that is connected to a standard color television receiver to display color images, each of which corresponds to the types of colors that can be displayed. a phase signal generating means for generating a plurality of phase signals having the same frequency and different phases; a color code signal comprising a phase selection code specifying hue and a level selection code specifying an element related to brightness; a plurality of phase signal selection means for selecting one of the plurality of different phase signals obtained from the phase signal generation means in response to a phase selection code from the color code signal generation means; level signal generating means for generating different voltage levels;
and by selecting two of the plurality of voltage levels generated by the level signal generating means based on the level selection code from the color code signal generating means, the bias level determined by the two voltage levels is superimposed. color signal output means for outputting a color signal having an amplitude of the selected phase signal and a phase of the phase signal selected by the phase signal selection means; This color encoder is characterized in that its bias level represents brightness, and its phase represents hue.

Operation The phase signal generating means multiplies a reference frequency signal, for example, a color subcarrier signal (3.58 MHz), by a factor of N, and uses the frequency signal of N times to generate, for example,
Generate 2N phase signals with mutually different phases.
The color code from the color code signal generating means consists of a phase selection code that specifies hue and a level selection code that specifies elements related to brightness.
In response to the phase selection code, phase signal selection means selects one of the plurality of different phase signals. The color signal output means selects two of the plurality of voltage levels generated by the level signal generation means based on the level selection code, and outputs an amplitude superimposed on a bias level determined by the two voltage levels. A color signal having a phase of the selected phase signal is output. Therefore, in this color encoder, the amplitude of the color signal represents saturation, the bias level represents brightness, and the phase represents hue.

Configuration Examples of the present invention will be described in detail below.

In FIG. 2 showing one embodiment, 10 is a color data generator that generates a data signal to be displayed on a display device, and the output signal is 5 per dot.
It shall be expressed in bits. 11 is RAM
A color generator consisting of (random access memory) generates a 6-bit color code signal.
Can store 32 pieces, color data generator 1
It is selected by color data signals from 0 and outputs one color code signal. The color code signal stored in the color generator 11 can be rewritten by the CPU 12.

13 is 6 times the frequency of the color subcarrier Sc (3.58MHz
×6) Create a frequency signal, and from that frequency signal
A phase signal generator that generates 12 (=2 x 6) types of phase signals with different phases; 14 is a phase selector, which receives 4 bits of the 6-bit color code signal sent from the color generator 11; Then, one of the 12 types of phase signals having different phases sent out from the phase signal generator 13 is selected and output. 15 inputs 2 bits of the color code signal sent from the color generator 11;
This is a decoder that converts into a four-level level selection signal.

16 is a resistor ladder, in which nine resistors 17-1 to 17-9 are connected in series between the power supply Vc.c. and ground (GND), and the transmission gate is connected from the voltage level position distributed by each resistor. Output signals are taken out through MOS transistors 18-1 to 18-8. transistor 1
8-1 to 18-8 are gate circuits 19-1 to 19
-4 so that they are controlled two at a time. Gate circuits 19-1 to 19-4 each have 2
A predetermined level selection signal from the decoder 15 is commonly input to one input terminal of both NAND circuits 20 and 21 in the same gate circuit. In addition, each gate circuit 19
A phase signal of a predetermined phase sent out from the phase selector 14 is commonly input to the other input terminal of one of the NAND circuits 20 of -1 to 19-4, and
The other input terminal of the NAND circuit 21 has one
The output signal of the NAND circuit 20 is input. The output terminals of each NAND circuit 20, 21 are connected to the gates of transistors 18-1 to 18-8, respectively.

The operation of this embodiment will be explained with reference to FIGS. 2 and 3.

When one piece of data is output from the color data generator 10, one color code signal (6 bits) is output from the color generator 11. Phase selector 14 selects four of the color code signals.
Bits are input, one type is selected from 12 types of phase signals having different phases, and the selected signal is sent to all gate circuits 19-1 to 19-4. Further, the decoder 15 receives two bits of the color code signal and sends a level selection signal to one of the gate circuits 19-1 to 19-4.

Now, for example, if the gate circuit 19-1 is selected by the decoder 15, the gate circuit 19
A low level signal is applied to one input terminal of each of the NAND circuits 20 and 21 in -1, and one input terminal of each of the NAND circuits 20 and 21 in other gate circuits 19-2 to 19-4. A high level signal will be applied to. Therefore,
When the phase signal from the phase selector 14 is at a low level, in the gate circuit 19-1, the output of the NAND circuit 20 is at a high level, the output of the NAND circuit 21 is at a low level, and the resistor ladder is at the voltage _V1 level position. The transistor 18-1 connected to the voltage V2 level is turned on, and the transistor 18-2 connected to the voltage _V2 level is turned off. Furthermore, when the phase signal is at a high level, the output of the NAND circuit 20 in the same gate circuit 19-1 is at a low level, so the output of the NAND circuit 21 is at a high level.
The transistor 18-2 connected to the voltage _V2 level position is turned on, and the transistor 18-1 connected to the voltage _V1 level position is turned off. The outputs from the other gate circuits 19-2 to 19-4 are all at low level, and the transistors 18-3 to 18-8 are off.

As a result, the signal output from the output terminal 22 is converted into a phase signal with a predetermined phase and an amplitude that oscillates at voltage levels _V1 and _V2, as shown in part A of FIG. The center level of the amplitude is the voltage level representing the brightness, resulting in a color signal. In this color signal, amplitude represents saturation and phase represents hue.

When another level is selected by the decoder 15 in response to another color data signal, for example, if the gate circuit 19-2 is selected, the voltage level between V ₃ and V ₄ as shown in part B of FIG. A color signal having an amplitude of , and a voltage level of the center voltage is output. Similarly, for the levels of other color codes, color signals with amplitudes and voltage levels shown in parts C and D of FIG. 3 are obtained.

Also, 4 for phase selection of other color data signals.
When a phase signal of another phase is selected by the bit code signal, the other phase (hue) having the amplitude (saturation) and voltage level (luminance) of one of A to D in Fig. 3 is selected. A color signal is output.

A color video signal is obtained by adding a burst signal and a synchronization signal to the color signal output in this way.

In this embodiment, 12 types of phase signals having different phases can each have four levels (amplitude and voltage level), so 48 types of colors can be generated. However, the color data generator 10
Since the color data signal from the 5-bit configuration is 5-bit, only 32 colors can be selected at one time. Therefore, in this embodiment, a color generator 11 that stores 32 6-bit color code signals is provided, and although 32 types can be selected by the color data generator 10, the stored contents of the color generator 11 are stored in the CPU 12. By rewriting the 6-bit color code signal, a maximum of 48 types (48 types of colors is the maximum in the method of this embodiment. Of the remaining codes, 4 are white →
Can be assigned as gray (2) → black. ) colors can be selected.

Effects As described above, according to the present invention, by appropriately setting the frequency of the phase signal generated by the phase signal generating means, it is possible to generate a number of color signals corresponding to the frequency of the phase signal. . Therefore, unlike the prior art cited above, the number of color signals that can be generated is not limited to eight colors, and any larger number of color signals can be generated.

By using the color encoder of the present invention, it is possible to express a wider variety of colors than when using a conventional color encoder which is limited in the number of colors that can be generated.This is particularly advantageous for video games or television game devices. Available for

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional color encoder, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a waveform diagram schematically showing the level of a color signal generated by the same embodiment. be. 10...Color data generator, 11...Color generator, 12...CPU, 13...Phase signal generator, 14...Phase selector, 15...Decoder, 16...Resistance ladder, 18-1~ 18-8...
...MOS transistor for transmission gate, 19-1 to 19-4...gate circuit.

Claims (1)

[Scope of Claims] 1. A color encoder that is connected to a standard color television receiver to display color images, each of which corresponds to the type of color that can be displayed, has the same frequency, and is in phase with each other. a phase signal generating means for generating a plurality of phase signals having different values; a color code signal generating means for generating a color code signal comprising a phase selection code specifying a hue and a level selection code specifying an element related to brightness; phase signal selection means for selecting one of a plurality of different phase signals obtained from the phase signal generation means in response to a phase selection code from the color code signal generation means; a level for generating a plurality of different voltage levels; signal generating means; and determining two voltage levels by selecting two of the plurality of voltage levels generated by the level signal generating means based on a level selection code from the color code signal generating means. color signal output means for outputting a color signal having an amplitude superimposed on a bias level and having a phase of the phase signal selected by the phase signal selection means; A color encoder characterized in that saturation is expressed by the amplitude of the color, brightness is expressed by the bias level, and hue is expressed by the phase. 2. The color signal output means includes: an output level designation means acting on the level signal generation means to designate two of the plurality of voltage levels as the maximum value and minimum value of the color signal; and driving means for generating a color signal having an amplitude that is in phase with the phase signal and oscillates between the two voltage levels by driving the output level specifying means in response to a level selection code. A color encoder according to claim 1. 3. The level signal generation means has a predetermined voltage applied to both ends thereof, connects a plurality of resistors in series, and generates a different voltage level from the connection point of each resistor, thereby generating a voltage level at the connection point of a pair of adjacent resistors. From 2
The output level specifying means includes a voltage dividing circuit for generating a color signal having an amplitude that oscillates between voltages, and one end of each of the output level specifying means is connected to a connection point of each resistor of the voltage dividing circuit, and the other end of the output level specifying means is connected to a connection point of each resistor of the voltage dividing circuit. The drive means includes a plurality of switching elements whose ends are connected to an output terminal, and the drive means selects any two of the plurality of switching means based on the phase signal and the level selection code, and selects any two of the plurality of switching means based on the phase signal and the level selection code, and 3. A color encoder according to claim 2, further comprising gate means for alternately driving two switching means in synchronization with a signal.