JPS622517B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color image receiving apparatus that sequentially samples and records/reproduces a group of outputs from a color demodulation circuit for a video signal outputting three primary color signals R, G, and B. The present invention relates to a color image receiving device developed for the purpose of preventing the color image receiving screen from being disturbed when the device is color killer.

Here, first, the primary color signals of the three colors R (red), G (green), and B (blue), which are used to drive the color picture tube as primary colors, are sampled line-by-line and written into a storage device.
By reading out these three primary color signals at the same time, a color image receiving device, large and small, can be used to obtain a color screen.
The explanation will be based on a drawing of a device configured with a screen.

1 is an antenna for receiving broadcast radio waves, M is a receiver for large screens, and it receives normal broadcast radio waves in R, G,
11 is a tuner for receiving the desired channel, 12 is an intermediate frequency amplifier, 13 is a video detector, 14 is a demodulation circuit for the chroma signal, a matrix circuit for the luminance signal, and a primary color signal. Outputs R, G, and B. S is a receiver for small screens, and like M, it includes a circuit for converting broadcast waves into three primary color signals of R, G, and B, and a storage circuit for this signal.

Figure 2 is a detailed block diagram of the small screen signal storage section and the circuit for inserting a small screen into any part of the large screen. 41 in the figure is a large screen color signal demodulation and matrix circuit. , 48 is a switching circuit for large screen and small screen, 49 is a clock signal generator for reading memory, 42 is a small screen color signal demodulation and matrix circuit, 43 is a switching circuit for primary color signals r, g, and b. 44 is an analog-to-digital conversion circuit for r, g, and b; 45 is a switching circuit for storing the digitally converted signal in the memory for primary color signals R, G, and B;
46 is a storage circuit for primary color signals, and 47 is a converter that converts the output from the storage circuit into an analog signal.

The operation will be explained below.

The signal for large screen is led to terminal M, and the color signal is 4
It is separated by a BPF (band pass filter) of 1, demodulated by a demodulator 2 of 41, and added to the luminance signal in a matrix circuit of 41 to produce R, G, B.
It is output as a primary color signal. This signal is the following 48
is input to the signal switching circuit.

On the other hand, the signal for the small screen is guided to the terminal S, and the color signal is separated by 42 BPFs (band pass filters), demodulated by 42 demodulators 1, and 42
is added to the luminance signal by the matrix circuit of
It is output as primary color signals of r, g, and b.

These r, g, b signals are 43 switch circuits
SW ₁ switches r, g, and b in sequence as shown in Figure 3 W, and inputs the input to the A/D converter 44. At the same time, the output of this A/D converter is sent to the switch circuit SW 45. Switched by ₂ ,
When inputting r, 46 memories [r,
Line switching signal to write to [MEMORY]
Controlled by S′. The line switching signal S' is obtained by generating three-phase pulses from the SB-HD pulse, which is the small-screen horizontal synchronizing signal shown in FIG. 3, using a ternary counter.

In other words, for the first line 1H, the r ₁ signal in Fig. 3 is selected by SW ₁ of 43 and SW ₂ of 45, and 44
The analog signal is converted into a digital signal via the 46 memory [r, MEMORY]. The next line writes the g ₂ signal in the same way,
Next, write the _b3 signal. Similarly, r ₄ , g ₅ , b ₆
While repeatedly writing one image to each of the 46 memories, r', which was written to the 46 memories,
The signals g' and b' are divided into r'' ₁ , g'' ₂ , b'' ₃ by clock 49 controlled by the small screen display signal S''.
are simultaneously read out and converted into analog signals r, g, and b by 47 digital/analog converters. Thereafter, each line r'' ₄ , g'' ₅ , b'' ₆ is read out as shown in Figure 3 Re.The primary color signal of the small screen from the D/A converter 47 is sent to the next stage switch circuit 48. It is switched by the small screen display signal S'' by SW ₃ , and is replaced with a part of the large screen. Of course, the r signal on the small screen is switched to part of the R signal on the large screen, the g signal is switched to part of the G signal, and the b signal is switched to part of the B signal.
Needless to say, switch to traffic lights.

When such composite signals R ₁ , G ₁ , and B ₁ are displayed on a color picture tube, a small color screen can be displayed within a large color screen.

However, as mentioned above, in the case of the method in which R, G, and B are taken out line-sequentially as small screen signals, even if the color killer circuit works in the color demodulator 42 due to reasons such as a weak electric field, the R, G, and B , B do not necessarily have the same waveform due to signals and noise, and meaningless colors remain on the small screen.

The present invention improves this point, and when the color killer circuit works, either R, G, or B
The output read from one memory 46 is output as a three-color signal on a small screen to a CRT, which is a color picture tube.
This prevents meaningless colors from being added to the small screen.

In FIG. 4, this can be realized by applying one of the outputs of the three-color memory 46 to the three-color D/A converter 47 via the data selector 50. , G, B, the killer signal from the color killer circuit of the demodulator 42
This is an example of switching using KS. Further, even if such a data selector 50 is inserted between 47 and 48, the result will be the same.

In the present invention as described above, the three primary color signals r, g, b from the color demodulation circuit 42 of the video signal S are
The primary color signals of the three stored colors are switched line by line, sampled line by line, and written to the storage device.
In a color image receiving device that simultaneously reads out and displays r′, g′, and b′, when the color killer of the color demodulation circuit 42 is activated, the read three color reproduction signals r″, g″, b″ are , which replaces any one of the primary color signals and displays it on the screen, and can prevent the display of the color image receiving device from being colored with meaningless colors due to noise or the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram showing a conventional example, FIG. 2 is a block circuit diagram of the main part of the same, FIG. 3 is a time chart explaining the same, and FIG. 4 is a block circuit diagram showing an embodiment of the present invention. It is. S: Color video signal, 42: Demodulation circuit, 4
6: Memory, 47: Digital/analog converter,
50: data selector, r, g, b: 3 color signals,
r′, g′, b′: 3-color signal, r″, g″, b″: 3-color signal,
KS: Killer signal.

Claims (1)

[Claims] 1. Three primary color signals from a color demodulation circuit for a color video signal are switched over time, sequentially sampled and written into a storage device, and these stored three primary color signals are simultaneously read out. A color image receiving device for displaying images, characterized by comprising means for replacing each of the three primary color signals read out with any one of the primary color signals when the color killer of the color demodulation circuit is activated. Color image receiving device.