JPH04282979A - Video signal processing unit - Google Patents

Abstract

PURPOSE:To always take pattern synchronization with respect to a master slave screen television receiver in which a slave pattern is inserted to part of a master pattern. CONSTITUTION:A synchronizing signal of a master pattern drawing is obtained by a synchronizing signal detection circuit 7 of a master pattern signal and when a synchronizing signal of the master pattern signal is lost, an input changeover circuit 8 is operated to give the synchronizing signal of the slave pattern to a master pattern signal processing circuit 2 to prevent synchronization flow on the television screen.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is directed to the P of a television receiver.
The present invention relates to a video signal processing circuit in the inP function.

0002

2. Description of the Related Art Hereinafter, a video signal processing circuit in a conventional parent-child screen simultaneous display function (hereinafter referred to as PinP function) will be explained with reference to the drawings.

FIG. 3 is a block diagram of a video signal processing circuit in a conventional PinP function. In the figure, 1 is a main screen mode selection circuit, 2 is a main screen signal processing circuit that processes main screen signals, 3 is a child screen mode selection circuit, and 4 is a child screen selected by the child screen mode selection circuit 3. A child screen processing circuit 5 that synchronizes the signal with the main screen signal and processes the child screen includes a main screen mode switching circuit 1 and a child screen mode switching circuit 3.
and a microcomputer 6 which outputs instructions regarding the child screen, and is a parent and child screen switching circuit which switches output signals from the main screen signal processing circuit 2 and the child screen signal processing circuit 4 in response to instructions from the microcomputer 5.

[0004] The operation of the video signal processing circuit in the PinP function, which is composed of the above-mentioned components, will be explained below.

[0005] A main screen mode selection circuit 1 selects a desired signal from among a plurality of input signals and inputs the main screen signal to a main screen signal processing circuit 2 . Here, the signals are converted into RGB color difference signals and input to the parent/child screen switching circuit 6.

On the other hand, the small screen signal is obtained by selecting a desired signal from among a plurality of input signals in a small screen mode selection circuit 3, and
The signal is input to the small screen signal processing circuit 4. Here, the signals are synchronized with the main screen signal, subjected to child screen processing, and then converted into RGB color difference signals and input to the parent and child screen switching circuit 6.

The parent screen signal and the child screen signal inputted to the parent and child screen switching circuit 6 are switched according to instructions from the microcomputer 5, and a signal is output in which the child screen is inserted into the main screen.

[0008]

However, since all of the child screen signals input to the parent/child switching circuit 6 are synchronized with the main screen signal, when the main screen signal becomes non-signal, the child screen signal Even if there is a video signal on the screen, the screen image will be a synchronized image on the screen.

The present invention solves these conventional problems, and provides video signal processing that always outputs synchronized child screen images even when the main screen signal becomes silent and the synchronization signal disappears. The purpose is to provide circuits.

0010

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a synchronization signal detection circuit for a main screen signal, and the detection signal is used to convert an input signal to the main screen signal processing circuit into a main screen signal. , and a small screen signal.

In addition, two main screen mode selection circuits are provided, a synchronizing signal detection circuit is connected to the output of one of them, and this detection signal is used to input an input signal to the other main screen signal processing circuit. The present invention includes a selection control signal switching circuit that switches the selection control signal of the mode selection circuit of the main screen to be selected into a main screen selection control signal and a sub-screen selection control signal.

0012

[Operation] With the above-described configuration, the present invention detects the synchronization signal of the main screen signal, and when the main screen signal has a synchronization signal, the output signal to the screen is synchronized with the main screen signal, and the main screen signal is detected. When there is no signal and the synchronization signal is lost, the output signal to the screen is synchronized with the sub-screen signal to prevent synchronization of the rendered screen.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A video signal processing circuit in the PinP function of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a video signal processing circuit according to a first embodiment of the present invention. In the figure, blocks 1 to 6 are blocks similar to those described in the section of the prior art. 7 is a synchronization signal detection circuit for the output signal of the main screen mode selection circuit 1; 8 is a detection signal from the synchronization signal detection circuit 7, which converts the input signal to the main screen signal processing circuit 2 into a main screen signal and a sub-screen signal. This is an input switching circuit.

[0015] PinP consists of the above-mentioned constituent blocks.
The operation of the video signal processing circuit in the function will be described below.

A main screen mode selection circuit 1 selects a desired signal from among a plurality of input signals, and inputs the main screen signal to a synchronizing signal detection circuit 7 and an input switching circuit 8.

On the other hand, for the small screen signal, the small screen mode selection circuit 3 selects a desired signal from a plurality of input signals, and
The signal is input to the small screen signal processing circuit 4 and the input switching circuit 8.

When the main screen signal includes a synchronization signal, the output signal from the input switching circuit 8 becomes the signal output from the main screen mode selection circuit 1, and the main screen signal processing circuit 2
is input to.

When the main screen signal becomes silent and the synchronization signal disappears, the output signal from the input switching circuit 8 is as follows.
This is the signal output from the sub-screen mode selection circuit 3,
The signal is input to the main screen signal processing circuit 2.

The main screen signal is processed by the main screen signal processing circuit 2.
The signal is converted into a GB color difference signal and input to the parent/child screen switching circuit 6.

On the other hand, the small screen signal is processed by the small screen signal processing circuit 4.
The signal is converted into an RGB color difference signal synchronized with the main screen signal and input to the parent/child screen switching circuit 6.

The parent screen signal and the child screen signal inputted to the parent and child screen switching circuit 6 are switched according to instructions from the microcomputer 5, and a signal is output in which the child screen is fitted onto the main screen.

As described above, according to this embodiment, when the main screen becomes silent, the screen is synchronized with the sub-screen synchronization signal, so no video is played.

Note that if the output signal from the mode selection circuit 1 of the parent screen is no signal, the content of the output signal from the parent screen signal processing circuit 2 will be the same as the content of the child screen signal. It is necessary to perform processing such as cutting the output signal from the main screen signal processing circuit 2 using the switching circuit 6.

FIG. 2 is a block diagram of a video signal processing circuit according to a second embodiment of the present invention. In the figure, blocks 2 to 6 are blocks similar to those described in the prior art section. 1 is a main screen mode selection circuit for selecting an input signal to the main screen signal processing circuit 2; 10 is a main screen mode selection circuit for checking the instruction from the microcomputer 5; 7 is a main screen mode A synchronization signal detection circuit for the output signal from the selection circuit 7, and a selection control signal switching circuit 9 that switches the selection control signal of the main screen mode selection circuit 1 into a main screen selection control signal and a child screen selection control signal.

[0026] PinP consists of the above-mentioned constituent blocks.
The operation of the video signal processing circuit in the function will be described below.

The main screen signal is sent to the main screen mode selection circuit 10.
A desired signal is selected from a plurality of input signals and input to the synchronization signal detection circuit 7.

If there is a synchronization signal in the input signal to the synchronization signal detection circuit 7, the output from the selection control signal switching circuit 9 becomes the main screen selection control signal, and the output from the main screen mode selection circuit 1 changes to the main screen mode. This signal is the same as the output signal of the selection circuit 10 and is input to the main screen signal processing circuit 2.

When the output from the mode selection circuit 10 of the main screen is no signal and there is no synchronization signal, the output from the selection control signal switching circuit 9 becomes the child screen selection control signal, and the output from the mode selection circuit 1 of the main screen is The output becomes the same signal as the output signal of the child screen mode selection circuit 3 and is input to the main screen signal processing circuit 2.

The subsequent operations are the same as those described in the prior art section. In this way, also in this embodiment, the first
As in the embodiment described above, when the main screen becomes silent, the screen is synchronized with the sub-screen periodic signal, so no video is played.

Note that if the output signal from the main screen mode selection circuit 10 is no signal, the contents of the output signal from the main screen signal processing circuit 2 will be the same as the contents of the child screen signal, so that the parent and child screens cannot be switched. Processing such as cutting the output signal from the main screen signal processing circuit 2 in the circuit 6 is required.

[0032]

Effects of the Invention As is clear from the above embodiments, the video signal processing circuit in the PinP function of the present invention can synchronize the output signal to the child screen even when the main screen signal becomes no signal and the synchronization signal disappears. By applying the screen signal,
It is possible to provide a video signal processing device that always displays synchronized screen images.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a video signal processing device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a video signal processing device according to a second embodiment of the present invention.

[Figure 3] Block diagram of a conventional video signal processing device

[Explanation of symbols] 1 Main screen mode selection circuit 2 Main screen signal processing circuit 3 Small screen mode selection circuit 4 Small screen signal processing circuit 5 Microcomputer 6 Parent and child screen switching circuit 7 Synchronization signal detection circuit 8 Input switching circuit 9 Selection control signal switching Circuit 10 Main screen mode selection circuit

Claims (3)

[Claims] 1. In a television receiver, main screen signal processing means of the receiver, sub-screen signal processing means fitted into the main screen, video signal synchronization detection means, and main screen signal processing controlled by the detection means. and means for constantly supplying a synchronization signal to the means. 2. A television receiver that simultaneously displays two images, a main parent screen and a sub-child screen, on one screen, comprising a main screen mode selection circuit, a child screen mode selection circuit, A main screen signal processing circuit that processes the main screen signal, a microcontroller that gives instructions to the main screen mode selection circuit and the child screen mode selection circuit, and a microcontroller that converts the child screen signal selected by the child screen mode selection circuit into the main screen signal. A child screen signal processing circuit that performs synchronized screen processing, a synchronization signal detection circuit for the main screen signal selected by the main screen mode selection circuit, and a detection signal from the synchronization signal detection circuit to the main screen signal processing circuit. An input switching circuit that switches input signals into a main screen signal and a child screen signal, and a main screen signal from the main screen signal processing circuit and a child screen signal from the child screen signal processing circuit according to instructions from the microcomputer. A video signal processing device equipped with a parent-child screen switching circuit. 3. In a television receiver that simultaneously displays a child screen within a main screen, the mode selected by first and second main screen mode selection circuits, a child screen mode selection circuit, and the first mode selection circuit. a main screen signal processing circuit that processes a main screen signal; a child screen signal processing circuit that processes a child screen signal selected by the child screen mode selection circuit in synchronization with the main screen signal; and the parent and child screen mode selection circuit. a microcomputer that gives instructions to the main screen, a synchronization detection circuit for the main screen signal selected by the second main screen mode selection circuit, and a main screen mode that selects the signal to be input to the main screen signal processing circuit based on the detection signal. A selection control signal switching circuit that switches the control signal of the selection circuit into a main screen selection control signal and a child screen selection control signal; A video signal processing device comprising a parent-child screen switching circuit that switches according to instructions from the microcomputer.