JPH0364273A - Blanking circuit - Google Patents

Abstract

PURPOSE:To arbitrarily set a state that blanking exists or not by switching a switch circuit by applying a blanking signal to a synthesizing circuit through the switch circuit. CONSTITUTION:A video signal processing circuit 1, a synchronizing signal processing circuit 2, a synthesizing circuit 3, and a switch circuit 4 are provided in an integrated circuit. In this case, in an input state of a switch switching signal input terminal 7, it becomes possible to transfer a blanking signal to the synthesizing circuit 3, therefore, it becomes possible to set a state that blanking exists or not to a video signal output terminal 6. In such a way, the state that blanking exists or not can be set by a switching control of the switch circuit. Also, a video output signal can be measured easily, and also, the measuring time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a blanking cycle 1@ used in a television receiver.

[Conventional technology]

Diagram IN3 is a block diagram of a conventional blanking circuit used in television receivers and the like.

In the figure, (1) is a video signal processing circuit, (2) is a synchronization signal processing circuit, (3) is a synthesis circuit, (5) is a video signal input terminal, and (6) is a video signal output terminal.

Next, the operation will be explained. Video signal input terminal (5)
A video signal as shown in Figure @a (&) is input to the . The video signal processing circuit (1) controls the image quality, contrast, brightness, etc. of the input video signal. On the other hand, the synchronization signal processing circuit (2) separates the synchronization signal and generates the blanking signal shown in FIG. 4(b) using the synchronization signal as a reference.

The synthesis circuit (3) inputs the video signal which is the output of the video signal processing circuit (1) and the output of the synchronization signal processing circuit (2), and outputs the synthesized signal as shown in No. 4vA(e) as a video signal. Output to terminal (6). This prevents the retrace period of the television image from being displayed on the screen.

[The problem that the invention attempts to solve]

Conventional blanking circuits have been constructed as described above.Recently, however, there has been an increasing demand for specifications with reduced blanking functions.

This is a system that superimposes an RGH on-screen display signal on the output signal of a video signal processing circuit as sets become more sophisticated.

When superimposing this RGB signal, it becomes necessary to transmit the black level information (approximately equivalent to the bank pouch of the synchronization signal), which is the reference level of the video signal, to the subsequent circuit, so integrated circuits without blanking circuit functionality are required to be used in series. There was a need to change it.

This invention was made to solve the problems of the conventional ones as described above, and aims to provide a blanking circuit that can be processed by a single integrated circuit.

[Means to solve the problem]

The blanking circuit according to the present invention is configured to apply a blanking signal generated by a synchronous signal processing circuit to a synthesis circuit via a switch circuit.

[Effect]

The blanking circuit according to the present invention is configured to apply the blanking signal to the synthesis circuit via the switch circuit, so that it is possible to arbitrarily set the state of blanking or not by switching the switch circuit.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (1) is a video signal processing circuit, (2)
is a synchronous signal processing circuit, <3) is a synthesis circuit, (4) is a switch circuit, (5> is a video signal input terminal, (6) is a video signal output terminal, (7) is a switch off g!! signal input terminal It is.

Among them, the basic operation is the same as the conventional one. However, in the input state of the switch changeover signal input terminal (7), it is possible to transmit the blanking signal to the synthesis circuit (3), so the blanking signal can be transmitted to the video signal output terminal (6) as shown in Figure 2. It becomes possible to set the status of ranking presence/absence.

〔Effect of the invention〕

As described above, according to the present invention, there is an effect that the blanking presence/absence state can be arbitrarily set by switching control of the switch circuit.

In addition, conventionally, when measuring potentials such as black level, it was necessary to set various conditions such as stopping the blanking signal, but according to the present invention, video output signals can be easily measured. Another effect is that the measurement time can be shortened.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a blanking circuit showing an embodiment of the present invention, Fig. 2 is a first output signal waveform diagram, Fig. 83 is a block diagram of a conventional blanking circuit, and Fig. 4 is a block diagram of a conventional blanking circuit. FIG. 3 is an output signal waveform diagram of FIG. In the figure, (1) is a video signal processing circuit, (2) is a synchronous signal processing circuit, (3) is a synthesis circuit, and (4) is a switch circuit. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 Figure 2

Claims (1)

[Claims] A video signal processing circuit, a synchronous signal processing circuit having a function of generating a blanking signal, a switch circuit receiving the blanking signal as input, and an output of the video signal processing circuit and an output of the switch circuit are input in an integrated circuit. What is claimed is: 1. A blanking circuit, comprising: a synthesis circuit, wherein the blanking circuit is capable of setting the presence/absence of a blanking signal.