JPS60112388A - A/d conversion method - Google Patents

Abstract

PURPOSE:To attain A/D conversion to a single picture of one scene by synchronizing changeover timing to an R, G, and B signals of a select switch with the sampling lock of an A/D converter, and converting the R, G, and B signals into picture element signals. CONSTITUTION:A composite picture signal 1 inputted in an input terminal 10 is divided by a decoder 1 into an R component signal 2, G component signal 3 and B component signal 4, which hold color components, and these signals are inputted respectively into a select switch 3, and a line synchronizing signal 11 separated by a synchronizing separator circuit 2 is inputted into a control circuit 4. The circuit 4 generates a sampling lock signal 5 synchronized with the synchronizing signal, by which controls an A/D convertor 5, memory 6 and changeover timing of said switch 3. The picture signals R, G, and B components in line are converted into digital picture element signals and are stored in the memory 6. The circuit 4 outputs the picture element signal inside the memory 6 after synchronizing the signal with the speed of a printer 7 by a calling signal from the printer 7.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an analog-to-digital conversion method, particularly to an analog-to-digital conversion method suitable for converting color image data at high speed. .

[Background of the invention]

Thermal transfer type thermal printers and inkjet printers are used as printers for making hard copies of Q color plans such as TVs, but these devices convert the analog signal No. 16, which is a uniform signal, into pixels. It is necessary to convert it into a digital signal to generate /:), and because the running speeds of -, 1, and + are different from each other, it is necessary to perform quick conversion.

For the former, the related analog-digital, (hereinafter A
For the latter, it is necessary to temporarily store and hold high-speed data and send it to the printer in response to a series of prints. Used. Memory valley exploration requires one screen.

When did these tremors become commercially available?

FIG. 1 is a conventional method for producing a color hard copy using such a converter memory.

The method shown in FIG. 2 is used. That is, the input terminal 10 is now receiving a multiple image signal ' shown in the diagram shown in FIG.
Inclusion 1 of Bjd (2), G signal (3), and B coast (4)
It is divided into numbers. At the same time, the 7-ray AltYJJ signal (6) divided h11 by the synchronization separation circuit 2, I
The IJ is processed by a microcomputer, etc., and 16
The signals are input to a control circuit 4 that controls/controls the timing of each section during signal input/output. The control circuit 4 receives a frame synchronization signal (
It generates a sampling clock signal synchronized with frame synchronization signal (6), controls the A/D converter 5 and memory 6, and controls the switching timing of the select switch 3.

Now, when the select switch 3 selects the hole bottom signal by the frame synchronization signal (6), the A/D converter 5 continuously samples the hole bottom analog image signal for one screen (frame), It is converted into a digital pixel signal and stored in memory. After one screen's worth of signals has been stored, the select switch 3 selects the G signal in response to the next frame synchronization signal, and the A/D converter 5 continuously converts the signal for one screen again. Next, in response to the third frame synchronization signal, the select switch 3 selects the B-signal, and the digital pixel signal converted for one screen is stored in the memory 6, similarly to the signal and the G signal. In this way, the B, G, and B signals stored in the king screen are sequentially read out in accordance with the speed of the printer 7 to form a hard copy color image.

In this block diagram, the device made in 1.a has a color image 1
It took the time of three frames to convert one screen of images into pixel signals, and the screen had the disadvantage that the screen would shake significantly at the darkest point on the video screen.

Figure 3 is also an example of a conventional conversion method, in which A/
It is equipped with a D converter 5. Therefore, during the -frame period, the G, G, and B signals can be converted to the pixel number 1d in the same way.

However, this method uses a large number of A/D converters and is therefore expensive.

[Purpose of the invention]

An object of the present invention is to provide an inexpensive method of A/D converting a single screen image at high speed by effectively adjusting the timing of the select switch.

[Summary of the invention]

In the present invention, by synchronizing the switching timing of the first switch to the 几, G, and B signals with the sampling clock of the A/D converter, the 几, G, and B signals are converted into pixels in a frame period. It is designed to convert into a signal.

[Embodiments of the invention]

FIG. 4 shows a block diagram of an embodiment of the present invention.

FIG. 5 shows signal waveforms at various parts, and the present invention will be explained in detail with reference to this.

In FIG. 4, a composite image signal (1) input to the input terminal 10 is divided by the decoder 1 into a hole bottom signal (2) having color components, a G component signal (0), and a B component signal (4). Line synchronization signals 11, which are input to the select switches 3 and separated by the synchronization separation circuit 2, are input to a control circuit 4, which is constituted by, for example, a microcomputer and controls the timing of inputting and outputting signals.

The control circuit 4 generates the next sampling clock signal (5) in synchronization with the synchronization signal, thereby controlling the A/D converter 5 and the memory 6 and also controlling the switching timing of the select switch 3. Now, when the select switch 3 selects the hole bottom signal based on the clock, the A/D converter 5 samples the hole bottom analog image signal at that clock timing, converts it into a digital pixel signal, and stores it in the memory. . The select switch 3 selects the G signal by the next S/Bring clock, and the A/D converter receives all of the G signals.
The components are digitized and sent to memory 6. The memory selects another address by the clock, and here, the digital G
Remember the ingredients. Furthermore, at the next clock, the select switch is switched to the bottom of the hole.

Thereafter, the above operation is repeated in the same way, and the 3, G, and B components of the image signal in the - line are converted into digital pixel signals. Therefore, one screen worth of (,,G,
All B components are digitized and stored in the memory 6. Thereafter, in response to a call 1 from the printer 7, the control circuit 1!4 outputs the drawing signal in the memory 6 in synchronization with the speed of the printer 7.

In this way, the present system can also convert a can image signal into a digital signal, and a color hard copy can be obtained using the gritter.

〔Effect of the invention〕

According to the present invention, an inexpensive and high-speed A/D conversion method can be obtained.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a conventional example, Fig. 2 is an operation waveform diagram of Fig. 1, Fig. 3 is a block diagram showing another conventional example, and Fig. 4 is a block diagram showing a conventional example.
The figure is a block diagram showing one embodiment of the present invention, and FIG.
It is a figure which shows the signal waveform of each part of a figure. 1...Decoder, 3...Select switch, 5...
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Claims (1)

[Claims] 1. A l'c analog-to-digital converter, comprising a decoder that divides color video signals into color number 1d, a switch that sequentially switches the color signals, and an A/D converter that converts the color signals into digital signals. J was there, and the day before the Mereki switch, was the timing of the A/D conversion of Kimi and No. 1D Noriaki? 7
This is an A/D conversion method whose special feature is synchronization with the knocking signal.