JP2578681B2 - Multi-screen display device - Google Patents

Description

The present invention relates to a multi-image display device that displays an enlarged image or the like on a regularly arranged display.

(B) Conventional technology The present applicant has already proposed a multi-screen display device for obtaining an enlarged image as Japanese Patent Application No. 1-244292.

This device is shown in FIG. In the figure, (1) is a first input terminal to which a composite video signal is input, (2) is a YC separation circuit that separates the composite video signal into a Y signal (luminance signal) and a chrominance signal (C signal), 3) is a second input terminal to which a YC separate video signal is input, and (4) is to input the output of the YC separation circuit and the Y signal and the C signal from the second input terminal (3), respectively, and select either. Switching circuit to output
(5) is a color demodulator that demodulates the C signal into two dye signals (RY) and (BY) signals, (6) is an A / D converter that A / D converts this output, ( 7) a video data bus for distributing A / D converted video data to a plurality of video data buses;
.. Are frame memories for storing the same data supplied from the video data bus, respectively. (9) controls writing and reading of the frame memory based on information from the input device (10) such as magnification, display position, etc. A microcomputer (hereinafter, referred to as a microcomputer) for controlling a first switch, which will be described later, has a back color function of outputting a single color regardless of an input video signal, and a back color and an input video signal. A color signal for satisfying special effect functions such as a color wipe function that switches and outputs a signal in the middle of one screen, and a color signal function that uses the input video signal data as the luminance signal and makes only the color signal an arbitrary single color , (12), (12)... Are controlled by the microcomputer and select a plurality of the frame memory outputs or the color signal generator outputs. The first switches (13) (13) are video signal processing circuits for adding a vertical and horizontal synchronizing signal to the output of the first switch, and for clamping a sync chip or pedestal level, and (14) (14). D / A converters for D / A conversion of the output of the video signal processing circuit, (15), (15) are signals that match the D / A conversion output with the input conditions of a display group (not shown), that is, a composite A modulator that modulates a video signal or a Y / C separated signal.

On the other hand, (16) is a PLL circuit which generates a color subcarrier synchronized with the burst signal in the output of the C signal of the switching circuit (4) and supplies it to each of the modulators.
And a phase comparator for comparing the phase of the VCO output with the input burst signal.
Consists of PF.

Reference numeral (17) denotes a synchronization separation circuit for separating a synchronization signal from the Y signal of the switching circuit (4), and its output gives a reference phase when the synchronization signal is added in the video signal processing circuit (13). .

 Next, the operation of the above-described circuit will be described.

First, the switching circuit (4) selects a Y signal and a C signal from the first or second input terminal (1) (3) according to an external switching signal. Then, the C signal is demodulated by a color demodulator (5) into a color difference signal (RY) signal and a (BY) signal, and the A / D-converted video data together with the Y signal is converted to a video data bus (7). ), Each frame memory (8)
(8) is supplied to. This frame memory is controlled to be written and read by the microcomputer (9), and is output as an enlarged video signal having a predetermined enlargement ratio.

The first switches (12) (12)... Normally select the frame memories (8) (8)... Outputs, and select the color signal generators (11) (11). The first switch outputs are further supplied to a video signal processing circuit (13), respectively.
(13) are supplied to the sync signal and the sync tip and the pedestal level are clamped. here,
Since the added synchronization signal is created based on the phase of the output of the synchronization separation circuit (17), the phase of the synchronization signal of the enlarged video signal matches the phase of the synchronization signal of the luminance signal before color demodulation.

Further, each output of the video signal processing circuit is connected to a D / A converter (1
4) (14) ..., after A / D conversion, modulator (15)
(15) ... Here, the color difference signal amplitude-modulates the color subcarrier, and is supplied as a composite video signal or a Y / C separation signal to each display (not shown) to display an enlarged image.

Since the color subcarrier generated by the PLL circuit (16) is used as the color subcarrier, the output after modulation matches the phase of the color subcarrier input to the color demodulator (5).

Therefore, if the horizontal frequency and the chrominance subcarrier frequency of the input video signal are in an interleaving relationship, the interleaving relationship is maintained for each of the modulator outputs, thereby preventing the occurrence of cross color and dot interference.

The color subcarrier from the PLL circuit (16) is also used for the color demodulator (5).

(C) Problems to be Solved by the Invention In the above-described conventional circuit, when the input video signal has jitter, that is, when it is a reproduction signal from a VTR or a VDP that has not been subjected to time axis correction, a special effect is obtained. When the color signal generator output is selected, the color signal generator output does not contain jitter, but the color subcarrier from the PLL circuit (16) contains jitter, so it is modulated by the modulator. The hue of the subsequent color signal changes on the screen, resulting in flicker.

The present invention solves the above-mentioned disadvantages. When an input video signal is selected, an interleaving relationship between a chrominance subcarrier frequency and a horizontal frequency of a signal after modulation is maintained, and a built-in video signal generating means is selected. An object of the present invention is to provide a multi-screen display device which is not affected by the jitter of an input video signal.

(D) Means for Solving the Problems The present invention provides a video data bus for distributing an input video signal to a plurality of video data buses, a plurality of video memories to which the same video data is respectively supplied from the video data bus; A color subcarrier generating means for generating a signal synchronized with a color subcarrier in a video signal; a video signal generating means for generating a video signal different from the input video signal; an output of the video memory or the video signal generating means A plurality of first switches for selecting a color subcarrier frequency; a fixed oscillator for oscillating at a color subcarrier frequency; output of the color subcarrier generation means when the first switch selects the video memory output in conjunction with the first switch. And a plurality of second switches for selecting the fixed oscillator output when the first switch selects the video signal generating means output; A plurality of modulation means for modulating at said first switch output, consisting of the modulation section outputted from the plurality of display means respectively displayed.

(E) Function By the above means, when the input video signal is selected, the modulator
By providing the color subcarrier from the PLL circuit, the interleaving relationship between the modulated color subcarrier frequency and the horizontal frequency is maintained, and when the built-in video signal generating means is selected, the modulator receives a signal from the fixed oscillator. The provision of the color subcarrier does not affect the input video signal at all.

(F) Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of the apparatus of the present embodiment, and the same parts as those of FIG.

The features of this embodiment are controlled by a fixed oscillator (18) and a microcomputer (9) that perform free-run oscillation at the color subcarrier frequency and output from the PLL circuit (16) or the fixed oscillator (18).
That is, a plurality of second switches (19) for selecting an output are provided.

The second switches (19), (19)...
2) (12). When the first switch selects the frame memory (8) (8)... Output, the second switch selects the PLL circuit (16) output, and When the switch selects the color signal generators (11), (11)..., The second switch selects the fixed oscillator output and supplies it to the modulators (15), (15).

Therefore, when displaying an image subjected to a special effect, the modulator is amplitude-modulated by the color signal generator output of the color subcarrier transmission from the fixed oscillator, so that the modulator is completely affected by the jitter of the input video signal. Without hue, stable hue is reproduced.

(G) Effects of the Invention As described above, according to the present invention, when the input video signal is selected, the interleaving relationship between the color subcarrier frequency and the horizontal frequency of the signal after modulation is maintained. The image quality is not degraded due to cross color or dot disturbance, and the input video signal is not affected by jitter when the built-in video signal generating means is selected.

[Brief description of the drawings]

FIG. 1 is a block diagram of a multi-screen display device according to an embodiment of the present invention, and FIG. 2 is a block diagram of a conventional example. (7) ... video data bus, (8) (8) ... frame memory, (11) (11) ... color signal generator, (12)
(12) ... 1st switch, (15) (15) ... modulator,
(16) PLL circuit, (18) Fixed oscillator, (19) (1
9) Second switch.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mitsunobu Enomoto 2-18-18 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd. (72) Inventor Tamiko Hirose 2-18-3 Keihanhondori, Moriguchi-shi, Osaka Yo Electric Co., Ltd.

Claims (1)

(57) [Claims] A video data bus for distributing an input video signal to a plurality of video data buses; a plurality of video memories to which the same video data is respectively supplied from the video data bus; a color subcarrier in the input video signal; A color subcarrier generating means for generating a synchronized signal; a video signal generating means for generating a video signal different from the input video signal; a plurality of first memories for selecting the video memory output or the video signal generating means output A switch, a fixed oscillator that oscillates at a color subcarrier frequency, interlocked with the first switch, and when the first switch selects the video memory output, selects the color subcarrier generation means output; A plurality of second switches for selecting the fixed oscillator output when the switch selects the output of the video signal generating means; and converting the second switch output with the first switch output. A multi-screen display device comprising: a plurality of modulating means for adjusting the tone; and a plurality of display means for displaying respective outputs of the modulating means.