JPS63209392A - Video processor - Google Patents

Abstract

PURPOSE:To reduce the number of A/D converters so as to simplify a circuit constitution by providing an analogue switch which sequentially selects and outputs one among plural kinds of inputted chrominance signals. CONSTITUTION:The analogue switch 14 sequentially selects only the chrominance signals required among respective chrominance signals of red, green and blue in a video display in a display device, and outputs them in series. Thus, the single A/D converter 16 converts the chrominance signals of one system which are sequentially selected and outputted in series into digital signals and they are sequentially written in a video memory 10. Namely, for the input to the A/D converter 16, the switch 14 selects the chrominance signals corresponding to the colors of respective dots (light emitting elements) and they are sequentially impressed in series. Thus, the A/D converter can be set in one system. Consequently, the number of A/D converters can be reduced and the circuit constitution can be simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a video processing device, and in particular, the present invention relates to a video processing device, and in particular, to reduce the number of parts and simplify the circuit by using a common A/D converter for multiple color signals. The present invention relates to a video processing device that has been transformed into a video processing device.

[Prior Art] FIG. 3 shows a schematic configuration of a video processing device used in a conventional video display device. The device in the figure has three A/
It is equipped with a D converter 2.4.6, a data selector 8, a video memory 10° such as a frame memory, and a timing generator 12.

Red, green, and blue color signals are input to each A/D converter 2, 4.6, respectively.
Both of the digital outputs 4 and 6 are input to the data selector 8, and one of these digital outputs is sequentially selected and output and written into the video memory 10. Further, the timing generator 12 generates a clock signal, a gate signal, etc. to be applied to each part from the input synchronization signal 5YNC.

In the video processing device shown in FIG. 3, it is assumed that, for example, a green color signal, ie, a G signal, and a blue color signal, ie, a B signal, have waveforms as shown in FIGS. 4(a) and 4(b), respectively, and the data selector 8 sequentially selects blue and green digital color signals and writes them into the video memory 10. In this case, the output of the data selector is shown in Figure 4 (C).
As shown, the signals correspond to the levels of each sampling point indicated by the circles of the 8 signal and the G signal, and these signals are sequentially written into the video memory 10. The video memory 10 includes, for example, memory elements B, G, B, G, . . . , G, R corresponding to light emitting elements of respective colors of a display device (not shown).

It has G,... Then, color signal data corresponding to each of these storage elements is sequentially written as described above, and the data is sequentially read out from the video memory in which the data has been written in this way, resulting in a display having light emitting elements of each color. The image is sent to the device and displayed as an image.

[Problems to be Solved by the Invention] In the conventional video processing device described above, input color signals of red, green, and blue are simultaneously sampled and A/D conversion is performed. This requires three systems, making the circuitry of the video processing device complicated and expensive. Furthermore, even though three A/D converters are provided, the color signal data required for actually displaying the image is of one color at the same time, and the color signal data of the other two colors are not required.

Therefore, in view of the problems with the conventional type, an object of the present invention is to reduce the number of A/D conversion circuits in a video processing device, thereby simplifying the circuit configuration and reducing costs, and improving reliability. It is about improving.

Means for Solving the Problems] The video processing device according to the present invention includes an analog switch that sequentially selects and outputs one of a plurality of types of input color signals, and an A/R connected to the output of the analog switch. A D converter is provided, and output data of this A/D converter is written into the video memory.

[Operation] In the above-described configuration, only the color signals sequentially required for displaying an image on the display device are selected from among the plurality of types of input color signals and output in series. Then, one system of color signals that are selectively output in series in this manner is converted into a digital signal by a single A/D comparator and sequentially written into the video memory. That is,
As input to the A/D converter, color signals corresponding to the colors of each dot (light emitting element) of the display device are selected by an analog switch and applied in series. As a result, A
/D converters can be integrated into one system.

[Example] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 schematically shows a video processing device according to an embodiment of the present invention. The device shown in the figure includes an analog switch 14 to which red, green, and blue color signals, that is, R signal, G signal, and B signal are input, and A to which the output of the analog switch 14 is input.
/D converter 16, a video memory 10, such as a frame memory, and a timing generator 18.
Equipped with: The video memory 10 is the same as in FIG. 3 and is therefore designated by the same reference numerals.

Also, unlike the device in FIG. 3, the device in FIG.
One system of /D converter 16 is sufficient.

Next, the operation of the video processing apparatus shown in FIG. 1 will be explained with reference to FIG. The G signal and B signal are respectively shown in Fig. 2(a).
and (b), these G and B signals are alternately selected and outputted by the analog switch 14, and the waveform at the input section of the A/D converter 16 is shown in FIG. 2(C). Become something. That is, in the apparatus shown in FIG. 1, only the color signals required for display by the display device are selected at the analog signal stage. The signals selectively output by the analog switch 14 in this manner are sampled at each sampling point indicated by a circle, and further A/D converted at the falling edge of the clock signal shown in FIG. 2(d). . The digital data thus obtained is equivalent to the digital signal obtained from the output of the data selector 8 in the apparatus shown in FIG. 3, and is sequentially written into the video memory 10. Note that the same operation is performed when the analog switch 14 sequentially selects the G signal and the R signal, and when the R signal, G signal, and B signal are sequentially selected.

[Effects of the Invention] As described above, according to the present invention, each color signal is converted into a serial format signal necessary for video display at the analog signal stage, and
After that, I started performing A/D conversion, so A/D
It becomes possible to use a single converter system, which reduces the number of parts in the video processing device, simplifies the circuit and reduces costs, and improves the reliability of the video processing device.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the general configuration of a video processing device according to an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining the operation of the device in FIG. 1, and FIG. , a block circuit diagram showing a general configuration of a conventional video processing device, and FIG. 4 a waveform diagram for explaining the operation of the device shown in FIG. 3. 2.4.6, 16: A/D converter, 8: data selector, 10: video memory, 12, 18: timing generator, 14: analog switch.

Claims (1)

[Claims] 1. An analog switch that sequentially selects and outputs one of a plurality of input color signals, an A/D converter that converts the output signal of the analog switch into a digital signal, and a surface It has a memory element corresponding to each color light emitting element of the display screen,
A video processing device comprising: a video memory into which digital signals output from the A/D converter are sequentially written. 2. The video processing device according to claim 1, wherein the analog switch sequentially selects and outputs necessary color signals in accordance with scanning of the display screen.