JPH04103281A - Television receiver with built-in teletext broadcast reception circuit - Google Patents

Abstract

PURPOSE:To inform a fact of the receiver not being out of order to the user by outputting an optional pattern from a character signal generating section in the inside of a teletext broadcast reception circuit and displaying the pattern onto a display device when a synchronizing signal is missing in a selected com posite video signal. CONSTITUTION:When a synchronizing signal is missing in a selected composite video signal, an optional pattern is displayed on a screen from a character signal generating section provided in the inside of a teletext broadcast reception circuit 4 via an IIC bus line from a channel selection microcomputer 3. When an idle channel of a high frequency signal input is selected or an external device is not connected to a video signal input terminal for the external device, a message or the like is displayed on the screen. Thus, the user recognizes it that the receiver is not out of order.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a television receiver with a built-in teletext receiving circuit.

(Prior Art) Conventionally, in a television receiver equipped with a built-in teletext receiving circuit, it is possible to select an empty channel of a high-frequency input television signal, or to receive a message when an external device such as a video device is not connected to the external input terminal. For example, when the external input mode is selected in the open state, the display screen may be a noise screen, an all-black state, or a blue-colored display.

(Problems to be Solved by the Invention) When a noise screen or an all-black or blue-colored display as described above appears, the user may mistakenly judge that there is a malfunction.

In view of the above-mentioned problems, the present invention utilizes various characters and patterns from a character generation circuit included in a teletext receiving circuit in selecting a receiving mode when there is an empty channel of high frequency input or when no external device is connected. To provide a television receiver with a built-in 11-character broadcast receiving circuit that can notify a user that there is no malfunction by displaying the following.

(Means for Solving the Problems) To achieve the above object, the present invention provides a television receiver with a built-in teletext receiving circuit that enables selective reception of a composite video signal of a high-frequency television signal and one of a plurality of composite video signals from an external device. When the synchronization signal is missing in the selected composite video signal, an arbitrary pattern is sent from the channel selection microcontroller to the text signal generator inside the teletext receiving circuit via the IIC path line. This is achieved by a television receiver with a built-in teletext receiving circuit.

(Function) With the above configuration, the present invention allows messages, etc. to be displayed on the screen when an empty channel for high frequency signal input is selected, or when no external device is connected to the video signal input terminal of the external device. , the user recognizes that the receiver is not at fault, and can therefore correctly recognize the channel selection.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a television receiver with a built-in teletext receiving circuit according to an embodiment of the present invention.

In the figure, 1 is an input switching circuit for a composite video signal obtained from high-frequency TV signal input and a video signal input from an external input terminal, and 2 is an input switching circuit that detects the presence or absence of a synchronization signal in the signal switched by input switching circuit 1. This is a synchronization signal detection circuit that outputs an H (High) level signal when there is no synchronization signal. In addition, 3 is a microcomputer for channel selection, and the I/O signal is determined by the synchronization signal presence/absence signal output from the synchronization signal detection circuit 2.
Controls the IC pass line. A teletext receiving circuit 4 is connected to and controlled by the channel selection microcomputer 3 through an IOC path line, and outputs a composite synchronization signal as well as an internal/external switching control signal for controlling switching thereof.

Furthermore, R and G generated internally.

Y outputs the B primary color signal and controls them.
Reference numerals 1 and 5 for outputting the S signal are switching circuits for switching between the composite synchronization signal outputted from the teletext receiving circuit 4 and the composite video signal switched input by the input switching circuit 1; 6 is a video chroma deflection circuit; The color difference signal of the input signal (
RY, G-Y, B-Y). 7 is a high-speed switching circuit that inputs RGB signals from the teletext receiving circuit 4;
The color difference signal inputted from the video chroma deflection circuit 6 is switched and outputted to the CRT drive circuit 8.

The present invention configured as described above operates as follows.

First, if a synchronization signal is included in the signal switched by the input switching circuit l, the synchronization signal detection circuit 2 is set to L (
The microcomputer 3 does not particularly control the IIC pass line, and therefore the teletext receiving circuit 4
sets the internal/external switching control signal to the L level, connects the switching circuit 5 to the input side of the output of the input switching circuit 1, sets the YS signal to the L level, and connects the high-speed switching circuit 7 to the color difference signals R, G, B. The color difference signal is output to the CRT drive circuit 8, and images are normally displayed.

Next, if there is no synchronization signal in the video signal input from the input switching circuit 1, this may be because an empty channel is selected or the external input terminal is in the oven, but the output of the synchronization signal detection circuit 2 is The channel selection microcomputer 3 controls the IIC pass line, outputs a composite synchronization signal from the teletext receiving circuit 4, sets the internal/external switching control signal to H level, and switches the switching circuit 5 to a. to the side. Furthermore, while outputting RGB signals, the YS signal is set to H level, causing the high-speed switching circuit 7 to switch to the R, G, and B signals from the teletext receiving circuit 4, and causing the CRT drive circuit 8 to display the signals on the CRT screen. In other words, in the case of a signal without a synchronizing signal, an arbitrary pattern generated by the teletext receiving circuit 4 is displayed on the CRT screen.

The present invention has been explained above, but if there is no synchronization signal,
Naturally, this also includes cases where the video signal input terminal is open.

(Effects of the Invention) As described above, the present invention checks the presence or absence of a synchronization signal, controls the teletext receiving circuit via the engineering IC path line of the channel selection microcomputer, and controls the teletext receiving circuit. This allows the user to arbitrarily display various characters and patterns on the video signal, and the user will notice that the video signal switching is incorrect. In other words, it can be easily determined that the receiver is not defective, so there is a benefit to using it.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a television receiver with a built-in teletext receiving circuit according to an embodiment of the present invention. 1...Input switching circuit, 2...Synchronizing signal detection circuit, 3...Microcomputer for channel selection, 4...Telecast receiving circuit, 5...Switching circuit, 6...Video chroma deflection circuit , 7...high-speed switching circuit, 8.
...CRT drive circuit. Patent applicant Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] (1) In a television receiver with a built-in teletext receiving circuit that can selectively receive a composite video signal of a high-frequency television signal and one of multiple composite video signals from an external device, a synchronization signal is added to the selected composite video signal. When it is missing,
A television receiver with a built-in teletext receiving circuit, characterized in that an arbitrary pattern is outputted from a channel selection microcomputer via an IIC bus line to a character signal generating section included in the teletext receiving circuit and displayed on a display. (2) The television receiver with a built-in teletext receiving circuit according to claim (1), wherein the loss of the synchronization signal includes a case where the input terminal of the composite video signal is open.