JPS60152191A - Picture display device - Google Patents

Abstract

PURPOSE:To obtain a picture display device capable of reproducing pictures faithfully by discriminating an input signal and inverting the phase of a sampling pulse of an A/D convertor at every one line enly when a component signal is selected. CONSTITUTION:Sampling pulses phi1 and phi2 which are generated in a sampling pulse generator circuit 102 and have the same period and inverted phases are supplied to a sampling pulse switching circuit 16, which is controlled by a sampling pulse control circuit 15. A signal output of a signal switching control circuit 5 and horizontal/vertical synchronizing signals are added to the sampling pulse switching circuit 15, and in accordance with the input signal status, the sampling pulse switching circuit 16 is controlled. Namely, the sampling pulse phi1 is always outputted at the time of selecting a composite image signal, but when the component signal is selected, the sampling pulses phi1 and phi2 are alternately outputted at every one line.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an image display device that displays images using an A/D converter.

(Configuration of conventional example and its problems) Conventionally, in this type of image display device, A
The sampling pulses supplied to the /D conversion circuit are the same. A conventional example will be explained below with reference to FIG.

The composite video signal is supplied to a signal switching circuit 4 through an input terminal 1, and the component signal is supplied to a signal switching circuit 4 through an input terminal 2. On the other hand, the signal for selecting the above signal is supplied via the input terminal 3 to the signal switching control circuit 5 for controlling the signal switching circuit 4. In the case of a composite video signal selected by the signal switching circuit 4, the video signal processing circuit 6
The signals are supplied to the signal processing circuit 8, undergo various signal processing, and are output as R, G, and B color signals, and are supplied to the signal switching circuit 8. Further, when a component signal is selected by the signal switching circuit 4, the signal processing circuits 71 to 7 are activated for each color signal.
The signals are supplied to the signal switching circuit 3, undergo various signal processing, and output color signals, which are then supplied to the signal switching circuit 8. The signal switching circuit 8 is
Controlled by the signal switching control circuit 5, switching is performed to select a signal synchronized with the signal selection of the signal switching circuit 4, and its output is supplied to the A/D and converters 9□ to 93. Hereinafter, only the color signal R will be explained.

The A/D converter 91 is supplied with the color signal R and the sampling signal generated by the sampling 7F signal ib generator IO1, outputs an n-bit digital signal (11 is an integer of 2 or more), and performs signal processing. , are supplied to the output circuit 111. Further, the signal processing/output circuit 11° is supplied with sampling pulses, etc. from the sampling pulse generation circuit 101, and is subjected to signal processing such as IH memory and pulse width modulation, and is then supplied to the image display 12 via the output circuit. (color signal G
The same applies to the single color signal B).

Also, in order to deflect the image display 12 in horizontal and vertical directions,
The signal selected from the signal switching circuit 4 is supplied to the synchronization signal processing circuit 13 to obtain a synchronization signal (horizontal synchronization signal: HD and vertical synchronization signal: VD) 'Th, which is supplied to the deflection signal processing output circuit 14, A necessary deflection voltage is applied to the image display device i2.

By the way, when the above-mentioned image display is installed and a digital component signal as shown in Figure 2 is input (for example, the video monitor output of a computer), the image that is faithfully reproduced is as follows. It will look like Figure 3. However, when the A/D converter samples at the rising edge of the sampling pulse, as shown in Figure 4, when the input signal is equal to or narrower than the sampling pulse width (
During the TA period), the input signal and the sampling timing may not match, and a faithful image as shown in FIG. 5 will not be reproduced.

(Object of the Invention) The present invention solves the above problems, and provides an image display device that can faithfully reproduce an image on an image display when a component signal of a digital signal is input and selected. The purpose is to

(Regeneration of the invention) The present invention i By determining the signal selection of the input signal of the sampling pulse of the A/D converter and inverting the phase for each line (IH) only when a component signal is selected, This system faithfully reproduces images based on human input signals.

(Description of Embodiment) One embodiment will be described below with reference to FIGS. 6 to io. In FIG. 6, the sampling pulse generation circuit 102
The period generated by is the same but the phase is reversed (180 degrees)
The sampling pulses φ1 and φ2 are supplied to a sampling pulse switching circuit 16, and the switching circuit 16 is controlled by a sampling pulse control circuit 15. The sampling pulse control circuit 15 is supplied with the signal output of the signal switching control circuit 5, a horizontal synchronizing signal: HD, and a vertical synchronizing signal: VD, and controls the sampling/gurus switching circuit 16 according to the state of the human input signal. If the composite video signal of the human input signal is selected, the sampling pulse'
It is switched so that fi-1 is always output from the sampling 0 ring pulse switching circuit 16. In addition, when the component signal is selected, the sampling nozzles φl and φ2 are alternately set for each line (IH), and the above operation is canceled every -vertical period by the vertical synchronizing signal: vD. Therefore, the same line (IH) has in-phase sampling and
The sampling pulse switching circuit 16 outputs the pulse signal.

The above explanation is shown in a timing diagram as shown in FIG.

FIG. 8 is a timing diagram of input signals, sampling pulses, and A/DX converter outputs from horizontal n lines to n + 3 lines according to the present invention, (a) is n line, (b) D
i n +1 line, (c) is n + 2 line, (→
shows the n+3 line.Hereinafter, only the period Tw of the input signal will be explained with reference to the same figure. If sampling of the A/D converter is performed at the rising edge of the sampling pulse, the sampling pulse of n lines (,) is
Assuming that, the output of the A/D converter is at a low level. Next, on the n + 1 line (b), the sampling pulse follows the path φ1 in the above explanation, and the phase is reversed to φ2 and 6.
The output of the p A/D converter becomes a no level. Next, on the +2 (C) line, the phase of the sampling signal is reversed and becomes φl, which becomes a low level as the output t of the A/D converter. Next, on the n+3 (d) line, the phase of the sampling signal is reversed and becomes φ2, and the output of the A/D converter becomes . . . level.

Similarly, according to the conventional method, as shown in FIG.
The output of the /D converter is at low level. Next, line n+1 (b), line n+2 (C), line n+3 (
Also in d), the output of the A/D & converter is at a low level because the Sun f IJ songs are φ□ and have the same phase.

Figure 10 is a diagram showing the above state reproduced on an image display device. Figure 10 (a) shows the case where the image is faithfully reproduced, Figure 10 (b) shows the reproduction of the image of the conventional example, and Figure 10 (C) shows the case where the image is reproduced faithfully. 1 shows the reproduction of an image according to the present invention, and as is clear from this figure, the present invention can reproduce a more faithful image compared to the conventional example.

(Effects of the Invention) As explained above, according to the present invention, when a component signal of a digital signal is input, a more faithful image can be reproduced by inverting the phase of the sampling pulse line by line. can.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the basic configuration of a conventional image display device, FIGS. 2 to 5 are diagrams for explaining the conventional example, and FIG. 6 is an image display device according to an embodiment of the present invention. 7 is a timing diagram of the horizontal synchronizing signal: HD and sampling pulse in the same embodiment, and FIGS. 8 and 9 are input signals and sampling pulses in the present invention and the conventional example, respectively. and a timing diagram of the A/D converter output, and FIG. 10 is a diagram showing the image reproduced on the image display. 1.2.3... Input terminal, 4, 8... Signal switching circuit, 5... Signal switching control circuit, 6... Video signal processing circuit, 71-73... Signal processing circuit, 9 ! ~93...
A/D converter, 101-102 ・Sampling pulse generation circuit, 111-113...Signal processing, output circuit, 1
2... Image display device, 13... Synchronous signal processing circuit, 1
4... Deflection signal processing, output circuit, 15. Zanf O-ring pulse control circuit, 16. Zanf O-ring/Grus switching circuit O Fig. 2 Fig. 3 n+3 line Fig. 4 Fig. 5 n line Fig. 8 Figure 9%p

Claims (1)

[Claims] The composite video signal input from the composite video signal input terminal is processed by the signal processing circuit, and the component signals (red, green, W, horizontal sync, and vertical sync signals) are input manually from the input terminal. The signal processed by the signal processing circuit is supplied to the signal switching circuit, the switching control signal is supplied from the switching control terminal to the signal switching circuit, the above signal is selected, and sampling occurs with the selected signal. Two types of sampling pulses with the same frequency and different phases generated by the component are discriminated by the control signal of the signal switching circuit, and if the composite signal is selected, the same sampling pulse is output, When a signal is selected, the sampling pulse is controlled to be outputted alternately for each horizontal line (IH) by an analog-to-digital converter. (A/D converter),
An image display device that supplies an A/D conversion output to a signal processing circuit, processes the signal, and supplies it to an image display device to display an image, the sampling signal of the A/D converter being input. An image display device characterized in that the phase is inverted for each line (IH) only when a component signal is selected by determining signal selection of a signal.