JPH1013759A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a television receiver with less disturbance on a screen even when a frequency of a synchronizing signal is different in the case of displaying a plurality of video signals with different vertical synchronizing frequencies on one image screen. SOLUTION: In the case of synthesizing a signal converted from a High Vision signal into an existing television signal by a conversion circuit 1 and the existing television signal at a signal processing circuit 3, when the presence of a High Vision signal is detected, the processing circuit 3 controls a synchronizing signal of the signal converted from the High Vision signal into the existing television signal is to be a reference signal at all times. Since a deflection pulse is synchronously with the High Vision signal, the disturbance on the High Vision signal is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver (International Patent Classification H04N 5/45) having a function of displaying a plurality of different video signals on one screen.

[0002]

2. Description of the Related Art In recent years, with widespread use of wide aspect television receivers, television receivers having a function of displaying a plurality of different video signals on one screen have become common. As means, a method of performing time operation on each of two video signals, switching and synthesizing the two video signals, as disclosed in Japanese Patent Application Laid-Open No. 7-298157, is performed.

[0003]

As described above, when two video signals are switched and combined and displayed on a screen, synchronization is separated from one of the main video signals to generate various timing signals. Need to be done. At this time, if the synchronization signal has the same frequency between the two video signals, it does not matter which of the video signals is used for synchronization,
When a synchronization signal, particularly a vertical synchronization signal, has a different frequency between two video signals, one main synchronization signal may cause interference with the other video signal.

Accordingly, a cathode ray tube (hereinafter referred to as C) is displayed on the image display section.
In a general television receiver using an RT (referred to as RT), a deflection yoke (hereinafter referred to as DY) for deflecting a beam of a CRT is provided with a deflection pulse generated by a synchronization signal generated from one video signal. However, at this time, the other video signal is disturbed by the radiation from the deflection pulse. Especially when the current television signal is used as a reference, the clamp level fluctuates when the HDTV signal receives the interference from the deflection pulse, which has a problem that the screen has a large influence such as flicker, and the influence of the interference is reduced. As a result, there are problems such as restrictions on the arrangement of components and wiring in the device.

[0005]

In order to solve the above problems, a television receiver according to the present invention selects an optimum vertical synchronization signal when displaying a plurality of video signals having different vertical synchronization frequencies on one screen. It is characterized by doing so.

According to the present invention, it is possible to provide a television receiver which has little influence on a screen even when a synchronization signal, particularly a vertical synchronization signal, has a different frequency among a plurality of video signals.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The first aspect of the present invention is to select an optimum vertical synchronizing signal when displaying a plurality of video signals having different vertical synchronizing frequencies on one screen. This has the effect of suppressing the influence of interference on the screen due to interference of one synchronization signal with the other video signal.

According to a second aspect of the present invention, there is provided a conversion circuit for receiving a Hi-Vision signal and converting it into a current television signal, and a signal processing circuit for synthesizing a normal current Television signal, and converting the Hi-Vision signal into one screen. The HDTV signal receives the radiation from the deflection pulse generated by the synchronizing signal of the current television signal when displaying the video signal by combining the current television signal and the ordinary current television signal, and the clamp level fluctuates. Has the effect of suppressing the influence of interference on the screen due to the operation.

According to a third aspect of the present invention, there is provided a decoder circuit for receiving and reproducing a Hi-Vision signal, and a signal processing circuit for synthesizing a normal current television signal. When displaying a video signal by synthesizing the signal with the signal, the HDTV signal receives the radiation from the deflection pulse generated by the synchronization signal of the current television signal, and the influence of the disturbance on the screen due to the fluctuation of the clamp level is suppressed. It has the action of:

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. (Embodiment 1) Hereinafter, claims 1 and 2 of the present invention will be described.
1 will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes a conversion circuit for receiving a Hi-Vision signal input from a terminal A and converting it into a current television signal. Reference numeral 2 denotes a normal current television signal input from a terminal B (hereinafter a signal a). And a signal converted from a Hi-Vision signal into a current television signal (hereinafter referred to as a b signal), and a signal processing circuit for outputting the signal to a terminal C. The signal processing circuit 3 separates a synchronization signal from each input signal. , A synchronous processing circuit for generating a reference pulse for driving a deflection circuit (not shown) and various timings. When two screens are simultaneously displayed in the television receiver configured as described above, one of the a signal and the b signal is selected as a reference synchronization signal. A detection signal is output to the synchronization processing circuit, and the presence or absence of a Hi-Vision signal is detected. Here, when it is detected that a Hi-Vision signal is present, the synchronization processing circuit 3 controls the synchronization signal from the signal b so that the reference signal is always used as a reference. Is suppressed.

(Embodiment 2) The first aspect of the present invention will be described below.
The embodiment described in claim 3 will be described with reference to FIG.

In FIG. 2, reference numeral 4 denotes a decoder which receives and reproduces a Hi-Vision signal inputted from a terminal A, and numeral 5 reproduces a normal current television signal (the former a signal) inputted from a terminal B and a Hi-Vision signal. A signal processing circuit for synthesizing the signal (hereinafter referred to as a c signal) and outputting the same to a terminal C. The signal processing circuit 3 separates a synchronizing signal from each input signal, and outputs a reference pulse and various signals for driving a deflection circuit (not shown). This is a synchronous processing circuit that generates timing. When two screens are simultaneously displayed in the television receiver configured as described above, one of the a signal and the c signal is selected as a reference synchronization signal. At this time, the lock detection from the decoder 4 is performed. The signal is output to the synchronization processing circuit, and the presence or absence of a Hi-Vision signal is detected. Here, when there is a Hi-Vision signal, the synchronization processing circuit 3 controls the synchronization signal from the c signal so that it is always used as a reference, so that the deflection pulse and the Hi-Vision signal are synchronized, so that interference with the Hi-Vision signal is suppressed. Will be.

Although the first embodiment has been described in connection with the case where there are two video input signals, the same effect can be obtained by controlling the synchronizing signal of the HDTV signal even if there are a plurality of input signals. Needless to say,

[0015]

As described above, according to the present invention, according to the television receiver of the present invention, a synchronization signal, particularly a vertical synchronization signal, can be obtained between a plurality of video signals by always selecting an optimum synchronization signal. Can provide a television receiver with less influence on the screen even when the frequency is different.

[Brief description of the drawings]

FIG. 1 is a block diagram of a television receiver according to Embodiment 1 of the present invention.

FIG. 2 is a block diagram of a television receiver according to Embodiment 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conversion circuit 2 Signal processing circuit 3 Synchronization processing circuit 4 Decoder A Hi-vision signal input terminal B Television signal input terminal C Composite signal output terminal

Claims (3)

[Claims] 1. A television receiver which selects an optimum vertical synchronizing signal when displaying a plurality of video signals having different vertical synchronizing frequencies on one screen. 2. The television receiver according to claim 1, further comprising a conversion circuit for receiving the Hi-Vision signal and converting it to a current television signal, and a signal processing circuit for synthesizing a normal current television signal. 3. The television receiver according to claim 1, further comprising a decoder circuit for receiving and reproducing the high definition television signal and a signal processing circuit for synthesizing a normal current television signal.