JPH0262593A - Character display device - Google Patents

Abstract

PURPOSE:To obtain a signal-colored character signal while signal is superposed upon a video signal from the beginning by specifying hue data recorded in a color ROM and reading color data out, and making the character data contain the hue data. CONSTITUTION:The color specification data of a RAM 12 for display is inputted to the color ROM 40 to read color signal data out. A composite video signal from an analog-digital convertor 50 is supplied to an output control part 41 and when the character data of a character generator 11 is at H level, the video signal on which the signal-colored character signal is superposed is supplied to a digital-analog converter 51.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a character display device used in combination with or incorporated in a television receiver, a video tape recorder, or the like.

(Prior Art) In recent years, channel and volume displays in television receivers and videotape recorders have been displayed directly on the screen as part of the image, instead of the conventional light-emitting element display or liquid crystal display. There are many ways to display it. In addition to channel display, display contents include time, date, title, equipment handling instructions, graph display, etc.

This type of display circuit does not display the signal sent from the broadcasting station as it is, but has a function of combining a signal with the content specified by the user into a part of the video signal.

FIG. 3 shows the building blocks of an integrated circuit developed as a so-called on-screen character display circuit.

Character specification data to specify the characters and figures to be displayed, color specification data to specify the display color, size specification data to specify the size of the letters and figures, and display position. Position designation data for this purpose is input via the decoder 10.

The character generator 11 stores pattern data such as various characters, 8 figures, etc., has a ROM (read only memory), and also stores external patterns into its RAM (random access memory) via the decoder 10. It can also store data.

Character designation data and color designation data are written to a display RAM (random access memory) via a write address counter 13.

Furthermore, the data that specifies the size of characters etc. to be displayed is
Data stored in the character size register 14 and determining where on the display screen to display is stored in the position register 15.

The character designation data CHD and color designation data CHD read from the display RAM 12 are supplied to the address of the character generator 11 and the control terminal of the output control section 30, respectively. In this case, control pulses are supplied to the display RAM 12 from the position/character size control circuit 16.

On the other hand, a digital composite video signal is supplied to the input section 20 and introduced into the sync separation circuit 23 . The horizontal synchronization signal and vertical synchronization signal separated by the synchronization separation circuit 21 are supplied to reset terminals of the horizontal position counter 23 and the vertical position counter 24, respectively. Horizontal position counter 2
3 counts the output pulses of the timing generator 22, and the output pulses with the period of wood hair are supplied to the clock input terminal of the vertical position counter 24.

Therefore, the horizontal position counter 23 and the vertical position counter 24
The count content represents the position information of the currently displayed display screen. The position information obtained by the horizontal position counter 23 and the vertical position counter 24 is input to the position/character size control circuit 16 and compared with the position designation data in the position register 15. The position designation data may be corrected according to the size designation data. When the position designation data matches the position information, the position/character size control circuit 16 supplies the control pulse described above to the display RAM 12 to output character designation data and color designation data. At this time, the position/character size control circuit 16 controls the control pulses given to the display RAM 12 in accordance with the size of the displayed characters.

The designated color data read from the display RAM 12 is supplied to the output control section 30, and the character designated data is supplied to the character generator 11. The specified character data read from the character generator 11 is input to the output control section 30.

output! 11 part 30, R (red), G (green), B (
Blue) Set and output each level of the signal. For example, if the specified color data is data specifying red, the R signal is output at the timing of, for example, a high level of the character tab.

The system also includes means for controlling the background of characters and the like. The background control data is also sent to the decoder 10.
can be stored in the background control register 18 via
The background control data is supplied to the background control section 19. The background control section 19 controls the output control section 30 according to the contents of the background control data, and performs control for specifying, for example, a color of gaps between characters and the like. For example, if the text color is set to red,
When the character data is at high level, the R signal is output, and when the character data is at low level, the G signal is selected and output.

A conventional character display circuit is configured as described above.

(Problems to be Solved by the Invention) As described above, according to the conventional character display circuit, the output signals that determine the colors of characters and background are R, G, and B.
It's a signal. Therefore, on the monitor side, use a model that supports R, G, and B output, or use a model that supports R, G, and B output.
It is necessary to convert it into a composite signal using an encoder, output it, and supply it to the video terminal of the monitor.

SUMMARY OF THE INVENTION An object of the present invention is to provide a character display device that can obtain a signal-colored character signal superimposed on a composite video signal from the beginning.

[Structure of the Invention] (Means for Solving the Problems) The present invention comprises a character generator ROM storing various character data, and a plurality of color burst data having different phases each stored for at least one period. Color RO that can output various specified color data by switching and specifying color burst data that is repeatedly read out of multiple types of data.
M, a display RAM that can store externally input character designation data and color designation data and provide these data as read addresses for the character generator ROM and color ROM, and a synchronization signal for the input composite video signal. and a display timing which obtains the readout timing of the character designation data and the color designation data of the display RAM in synchronization with the color burst and color burst signals, and controls the readout of the designated character data of the character generator ROM and the designated color data of the color ROM. a control section; and an output control section to which at least the specified character data, specified color data, and composite video signal are supplied, and which combines and outputs the specified character data signal-colored by the specified color data with the composite video signal. It is equipped with.

(Operation) By specifying the hue data stored in the color ROM by the above means, the hue data can be easily included in the character data, and furthermore, this data can be superimposed on the composite video signal.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. 1 differs from the conventional circuit shown in FIG. 3 in that a color ROM 40 is provided and an output control section 41 is configured to output a composite video signal. That is, the color specification data in the display RAM 12 is the color RO
Supplied to M40. This color ROM 40 stores at least one cycle of a plurality of color burst data having different phases, and outputs various designated color data by switching and specifying the color burst data to be read out repeatedly among the plurality of types of data. can do. As shown in FIG. 2, the color ROM 2O stores multiple types of burst data 4a, 4b, 4c, . . .
are stored, and the selection of read data can be switched.

This color data is color signal data itself, and in the output control section 41, for example, when character data is at a high level, it is superimposed on this and further inserted into the composite video signal.

A digital composite video signal from an analog-to-digital (A/D) converter 50 is supplied to the output control section 41, and if no characters are inserted, the signal is supplied to the digital-to-analog converter 51 as is. However, when a character signal is superimposed, the character signal colored by the above-described operation is supplied to the digital-to-analog converter 51 as a video signal superimposed thereon.

Note that other parts are the same as the conventional circuit shown in FIG. 3, and are given the same reference numerals as in FIG. 3.

As described above, according to this embodiment, when character data is inserted into a video signal, it can be inserted into the video signal itself as an already colored signal. Moreover, many types of colors can be selected by storing burst data of various phases in the color ROM 40. In addition, the analog-to-digital converter 5
The system clock for digitization at 0 is stably phase-locked to the color burst of the human video signal. Therefore, since the read clock in the color JOM 40 also uses the system clock, the read color signal phase for coloring maintains a stable and accurate phase relationship with respect to the burst signal.

[Effects of the Invention] As described above, according to the present invention, it is possible to obtain a colored character signal superimposed on a composite video signal from the beginning.

For this purpose, there is no need to use a conventional monitor having R, G, and B terminals. Furthermore, stable and accurate coloring can be obtained for characters.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is an explanatory diagram of the configuration showing an embodiment of the present invention, FIG. 2 is an explanatory diagram of the color ROM shown in FIG. 1, and FIG. 3 is an explanatory diagram of the configuration of a conventional character display device. It is a diagram. 10... Decoder, 11... Character generator, 12... Display ROM, 13... Write address counter, 14... Character size register, 15...
・Position register, 16...Position/character size control circuit, 18...Background register, 19...Background control unit, 2
DESCRIPTION OF SYMBOLS 1... Synchronization separation circuit, 22... Timing generator, 23... Horizontal position counter, 24... Vertical position counter, 40... Color ROM, 41... Output control section, 50... Analog-digital converter, 51...
Digital to analog converter. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] A character generator memory storing various character data, and a plurality of color burst data having different phases each stored for at least one period, and color burst data to be repeatedly read out of the plurality of types of data. A color ROM that can output various specified color data by switching and specifying the data, and a color ROM that stores externally input character specification data and color specification data, and reads these data from the character generator memory and the color ROM. A display RAM that can be given as an address, and a read timing of the character designation data and color designation data of the display RAM in synchronization with the synchronization signal and color burst signal of the input composite video signal, and the character generator memory. a display timing control unit that controls reading of specified character data and specified color data of a color ROM; and at least the specified character data, specified color data, and composite video signal are supplied, and the composite video signal is colored with the specified color data. and an output control section that synthesizes and outputs the designated character data.