JP2985094B2 - Background color output circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a background color output circuit that switches a background color by a color system of a television receiver that supports multiple systems such as the PAL / NTSC / SECAM system. The present invention relates to a background color output circuit that controls background color output in conjunction with noise reduction control.

(Prior Art) Currently, television receivers have a background color output function that makes the entire screen monochromatic in blue without a video signal input from AV equipment or the like with the spread of AV equipment such as VTRs and video discs. Equipped things are becoming more common.
This is merely to make the entire screen have the same background color, and the background color output cannot be canceled.

Hereinafter, an example of the above-described conventional background color output circuit will be described with reference to the drawings.

FIG. 3 shows a circuit configuration of a conventional background color output circuit. In FIG. 3, reference numeral 31 denotes a synchronization signal detection circuit, 32 denotes an output switching circuit for turning on / off the background color, 33 denotes a microcomputer, 34 denotes a video signal processing circuit, 35 denotes a resistor, and 36 denotes a power supply.

The operation of the circuit connected as described above will be described below.

The video signal is supplied to a video signal processing circuit 34, where processing according to the color system signal output from the microcomputer 33 is performed according to the color system setting, and at the same time, various screens such as channels and volume from the microcomputer 33 are provided. The on-screen display signals R, G,
B, Mixing with blanking signal is performed. The video signal is also supplied to the synchronization signal detection circuit 31, and if there is no synchronization signal, the detection output is sent to the output switching circuit 32, and the output switching circuit 32 performs the ON operation of each of SW1 and SW2. As a result, the signal B is superimposed on the B signal and the blanking signal from the power supply 36 via the power supply limiting resistor 35, and the entire screen is displayed with a blue background color.

When there is a synchronization signal, no detection output is output from the synchronization signal detection circuit, the output switching circuit 32 is turned off, and the background color is not displayed.

(Problems to be Solved by the Invention) However, the conventional background color output circuit as described above merely makes the entire screen the same background color. That is, the user of the television receiver could not select a color. In addition, if the electric field strength is weak, it is determined that there is no signal, and if the background color output circuit operates, it cannot be released because the background color output circuit cannot be released, which makes it difficult to use the television receiver in the weak electric field area. I was

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional disadvantages, to enable a user of a television receiver to select a plurality of colors, and to control the operation of a background color output circuit by a noise reduction control signal. A color output circuit is provided.

(Means for Solving the Problems) A background color output circuit according to the present invention is a background color output circuit for displaying a background color on the entire screen of a television receiver capable of supporting multi-system television signals. Synchronization signal detection means for detecting a synchronization signal from a signal and outputting a detection signal when no synchronization signal is detected, and color system setting means for setting a color system of the television receiver to a method according to an input television signal And control means for outputting a color system signal, an on-screen signal, and a noise reduction control signal in accordance with the setting of the color system setting means, and processing the video signal in accordance with the color system signal output from the control means. Video signal processing means for performing a mixing process of an on-screen signal output from the control means and the video signal; A first switching unit for selecting a background color to be displayed from a plurality of background colors in accordance with the color system signal; and switching control by a detection signal output from the synchronization signal detecting unit to display or hide the background color. Second switching means for setting, and third switching means controlled by the noise reduction control signal to turn on and off the output of a detection signal from the synchronization signal detecting means for switching and controlling the second switching means. When the detection signal is output from the synchronization signal detection unit, the second switching unit is turned on to display a background color, and when the noise reduction control signal is output, the third switching unit is turned on. It turns off the display of the background color.

(Operation) The present invention enables the user of the television receiver to select a plurality of colors by the above configuration. Further, it is possible to control the display / non-display of the background color by the noise reduction control signal.

Embodiment A background color output circuit according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a circuit configuration of a background color output circuit according to a first embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a synchronization signal detection circuit, 12 denotes an output switching circuit for turning on / off a background color, 13 denotes a color switching circuit, and 14 denotes a color switching circuit.
Is a microcomputer, 15 is a video signal processing circuit, 16 is a resistor, 17 is a power supply, 18 is an image quality control circuit, and 19 is a detection output switching circuit.

The operation of the circuit connected as described above will be described below.

The video signal is supplied to a video signal processing circuit 15, where processing according to the color system signal output from the microcomputer 14 is performed in accordance with the color system setting, and various screens such as channels and volume from the microcomputer 14 are simultaneously output. The on-screen display signals R, G,
B, Mixing with blanking signal is performed.

The video signal is also supplied to the synchronization signal detection circuit 11 and when there is no synchronization signal, the detection output is changed to the detection output switching circuit 19.
Sent to Normally, the noise reduction control signal is not sent from the microcomputer 14, and the detection output switching circuit
19 is closed. Therefore, the detection output is sent to the output switching circuit 12, and the output switching circuit 12 performs the ON operation of each of SW1 and SW2. SW1 superimposes the blanking signal from the power supply 17 via the current limiting resistor 16 while the SW2 leads from the power supply 17 via the current limiting resistor 16 to the color switching circuit 13, and the color switching circuit 13 After performing a switching operation on each of the output terminals a, b, and c, the signals are superimposed on the respective signals of R, G, and B.

For example, when switching to a for the PAL system, b for the SECAM system, and c for the NTSC system, the R signal for the PAL system, the G signal for the SECAM system, and the B signal for the NTSC system, respectively. Becomes

As a result, the background color corresponding to the color system is displayed on the entire screen.

Here, when canceling the background output, the microcomputer 14 sends a noise reduction control signal to the image quality control circuit 18 and the detection output switching circuit 19 to send the noise reduction control signal.
Performs noise suppression. At the same time, the detection output switching circuit 19 stops supplying the open detection output to the output switching circuit 12 and stops displaying the background color.

If there is a synchronization signal, no detection output is output from the synchronization signal detection circuit, and the output switching circuit 12 is turned off, so that the background color is not displayed.

As described above, according to the present embodiment, the conventional background color output circuit is provided with the color switching circuit linked to the color system, so that the user of the television receiver can perform the setting operation of the color system to obtain a plurality of background colors. Can be selected.

When noise is conspicuous in a weak electric field state or the like, when the user of the television receiver selects the noise reduction function, the background color output circuit also stops operating.

Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows a circuit configuration of a background color output circuit according to a second embodiment of the present invention. In FIG. 2, reference numeral 21 denotes a synchronization signal detection circuit, 22 denotes a microcomputer, 23 denotes a video signal processing circuit, and 24 denotes an image quality control circuit.

The operation of the circuit connected as described above will be described below. The video signal is supplied to a video signal processing circuit 23, where processing according to the color system signal output from the microcomputer 22 is performed according to the color system setting, and at the same time, various screens such as channels and volume from the microcomputer 22 are provided. A mixing process is performed with R, G, B, and blanking signals, which are on-screen display signals. The video signal is also supplied to a synchronization signal detection circuit 21, and if there is no synchronization signal, a detection output is supplied to the microcomputer 22. When the microcomputer 22 receives the detection output, the blanking signal and the R, G, B signals corresponding to the given color system are output as the background color.

For example, the R signal is used in the PAL system, and the G signal is used in the SECAM system.
The signal is output in the form of a signal and a B signal in the case of the NTSC system. As a result, a background color corresponding to the color system is displayed on the entire screen as in the first embodiment. When the noise reduction function is operated, the microcomputer 22 sends a noise reduction control signal to the image quality control circuit 24, and the image quality control circuit 24 performs noise suppression. At the same time, the microcomputer 22 stops outputting the blanking signal, R, G, and B signals, and stops outputting the background color.

As described above, according to the present embodiment, the color switching means for performing the switching operation in accordance with the color system signal is provided in the microcomputer, so that the user of the television receiver performs the color system setting operation, thereby Can be selected.

Further, when noise is conspicuous in a weak electric field state or the like, when the user of the television receiver selects the noise reduction function, the operation of the background color output circuit is also stopped.

(Effect of the Invention) According to the present invention, by performing switching control of the background color corresponding to the color system, the user of the television receiver can select a plurality of background colors by performing the setting operation of the color system. become.

Further, by turning off the second switching means by the noise reduction control signal, if the noise is conspicuous in a weak electric field state or the like, when the user of the television receiver selects the noise reduction function, the third function is activated. Is turned off, the detection signal is not input from the synchronization signal detecting means to the second switching means, and the second switching means switches the background color to non-display, thereby canceling the background color output. Becomes As a result, no trouble occurs even when the television receiver is used in a weak electric field area, and the practical effect is great.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of a background color output circuit in a first embodiment of the present invention, FIG. 2 is a circuit configuration diagram of a background color output circuit in a second embodiment of the present invention, and FIG. FIG. 3 is a circuit configuration diagram of a background color output circuit. 11,21 ... Synchronous signal detection circuit, 12 ... Output switching circuit, 1
3 ... Color switching circuit, 14,22 ... Microcomputer,
15, 23 ... video signal processing circuit, 16 ... resistor, 17 ... power supply, 18, 24 ... image quality control circuit, 19 ... detection output switching circuit.

Claims (1)

(57) [Claims] A background color output circuit for displaying a background color on the entire screen of a television receiver capable of supporting a multi-system television signal, comprising: detecting a synchronization signal from a video signal; A synchronization signal detecting means for outputting a detection signal when there is no color signal; a color system setting means for setting a color system of the television receiver to a method according to an input television signal; and a color system according to the setting of the color system setting means. Control means for outputting a system signal, an on-screen signal, and a noise reduction control signal; processing a video signal in accordance with a color system signal output from the control means; an on-screen signal output from the control means; Video signal processing means for performing a mixing process with a video signal; and a plurality of backgrounds according to the color system signal. A first switching unit for selecting a background color to be displayed from the second unit; a second switching unit that is switched and controlled by a detection signal output from the synchronization signal detection unit and sets display or non-display of the background color; A third switching unit controlled by a reduction control signal to turn on and off the output of a detection signal from the synchronization signal detection unit that switches and controls the second switching unit; and a detection signal is output from the synchronization signal detection unit. When the noise reduction control signal is output, the second switching means is turned on to display the background color, and when the noise reduction control signal is output, the third switching means is turned off to cancel the display of the background color. A background color output circuit.