JPS6212285A - Teletext receiving device - Google Patents

Abstract

PURPOSE:To eliminate such an unnatural phenomenon that a teletext image surface before switching remains by detecting a status signal generated in channel selecting operation, erasing a teletext image surface with the signal, and searching for a new teletext page in a series of operations. CONSTITUTION:When a channel B is changed to a channel B while the teletext image surface is watched, a receiving device is reset to a television mode then then the channel B is selected to make a change from the television mode to the teletext mode. At this time, a selecting device 8 generates the status signal and when a system control circuit 14 detects this signal, the teletext image surface of the channel A before the switching is erased through a CPU 16 and a page of a magazine of the channel B after the switching is searched for. Consequently, such an unnatural phenomenon that the teletext image surface of the station A before switching remains when the channel is switch to a broadcasting program of the station B is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a teletext receiving device for receiving teletext broadcasts.

Conventional Technology In recent years, with the start of teletext broadcasting that uses gaps in television radio waves to send text and graphic information, various industries have been active in developing and commercializing teletext receiving devices. I've started.

Conventional teletext broadcast receiving devices have been limited in transmission content, with only one broadcasting station or at most two broadcasting stations, including experimental ones, providing teletext information.

Problems to be Solved by the Invention However, unlike the above case, when the number of broadcasting stations increases, the following problems occur.

That is, suppose that the user initially receives a television channel of a broadcasting station provided by company A, and detects and watches a teletext screen carried on the television radio waves.

Next, when you change the channel to the TV channel of the broadcasting station provided by 8 companies, only the last page of the teletext broadcast detected by the previous company provided by MU remains on the teletext screen on the channel provided by 8 companies. Therefore, the teletext screen provided by company A will remain until the teletext mode is switched again on the channel provided by company 8 and the teletext screen provided by company A is detected until the page number of the teletext broadcast is detected.

Therefore, the above method has a problem in that unnatural phenomena occur from the perspective of the user of the teletext receiving device.

In view of the above-mentioned problems, the present invention provides a teletext receiving device that automatically erases the teletext screen of the previous channel when switching TV channels and detects the first teletext page of a new TV channel. This is what we are trying to provide.

Means for Solving the Problems In order to achieve this object, the teletext receiving device of the present invention detects a status signal generated during channel selection operation of a television receiver, and uses the status signal to The system is configured so that a series of operations such as erasing the teletext screen and then searching for a new teletext page can be performed.

Effect: This configuration eliminates the unnatural phenomenon that when the channel is switched from station A to station B, the teletext screen of station A remains on the broadcast program of station B.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to block diagrams and flowcharts.

FIG. 1 shows a block diagram of a teletext receiving apparatus in an embodiment of the present invention.

In FIG. 1, 1 is a tuner, 2 is an intermediate frequency amplification circuit,
3 is a video detection circuit, 4 is a video amplification circuit, 6 is a switching circuit between a normal television signal and a teletext signal, 6 is a CRT,
7 is a color demodulation circuit, 8 is a tuning circuit, 9 is a synchronization separation circuit, 1
0 is a deflection circuit, and 1 to 4; 6 to 1o are the configuration of a normal color television receiver.

11 is a data slice circuit for extracting a teletext signal from a television signal; 12 is a clock generation circuit for generating a clock signal as a reference for operation; and 13 is for extracting only text/graphic information including control information requested by the user. a data extraction circuit, 14 a system control circuit, 16 a display signal generation circuit, 16 a CPU,
17 is a RAM for writing coded character/graphic information and executing programs; 18 is a ROM for storing programs; 19 is a RAM 17
A video RAM control circuit is used to pattern the character/graphic information that continues from 20 to 20, and 2o is a D/RAM converter circuit. The output of this D/A' converter 2o is supplied to a television/text signal switching circuit 6.

The operation of the teletext receiver configured as described above will be explained below. First, a data slicing circuit 11 and a data extracting circuit 13 extract necessary portions of the teletext signal transmitted from a broadcasting station via television broadcasting waves. That is, the data slice circuit 11 and the data extraction circuit 13 extract only the coded character and graphic signals from the video signal detected by the video detection circuit 3 through the tuner 1 and the intermediate frequency amplification circuit 2.
The PU 16 performs arithmetic processing, writes it to the RAM 17, and reads it out.The video RAM control circuit 19 converts it into a pattern, and the D/MU converter 2o converts it into an analog signal, which is then supplied to the television/teletext signal switching circuit 6. If the teletext mode is selected, the analog text/graphic information is selected and displayed on the C1RTe.

In this case, assume that you are watching the teletext screen while receiving the broadcast station channel /L/(person channel/v)k that you originally joined the company. Next, when switching channels to receive the B company broadcasting station channel (B channel), the channel operation method is to first return the current teletext mode to TV mode, then select B channel and switch from TV mode. You need to switch to teletext mode F again. Each time this operation (mode switching) is performed, the channel selection device 8 generates a status signal and changes the code of the status signal for each mode, but in the illustrated example of the present invention, this status signal is controlled by the system. circuit 14
If a status signal is detected when changing from TV mode to Teletext mode, CPU
16i to erase the teletext screen of the human channel before switching, and to search the magazine ρ paging of the B channel after switching.

The flowchart of the program is shown in FIG. Second
In the figure, first, in step 31, the interrupt (data detection) process repeatedly reads the status every 1/60 seconds, and determines whether the mode is teletext mode (step 32). If the teletext mode can be detected based on this status signal, it is determined whether the mode already written in the RAM 17 is teletext or not (step 33).
If it is not teletext, the code signal (status signal) of the teletext mode is written into the i7 RAM 17 (step 34) and the screen is erased (step 35).
). If it is not the status signal of the teletext mode in step 32, and if the status signal of the teletext mode is already stored in step 33,
The signal is written into the RAM 17 (step 36) and programmed to proceed to the next step.

Effects of the Invention As described above, according to the present invention, by detecting the status signal obtained when switching from television mode to teletext mode and erasing the screen, it is possible to switch to the broadcast program of station B. In this case, it is possible to eliminate the unnatural phenomenon in which the teletext screen of station A before switching remains.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a teletext receiving apparatus according to an embodiment of the present invention, and FIG. 2 is a flowchart for explaining the operation of the main part of FIG. 8...Tuition selection circuit, 11...Data slice circuit, 13...Dener extraction circuit, 14...
...System control circuit, 16....--
Name of CPU0 agent: Patent attorney Toshio Nakao and one other person Figure 1 Figure 2

Claims (1)

[Claims] The system is configured to extract text and graphic information superimposed on a television broadcast signal and transmitted separately from a normal video signal, and reproduce the text and graphic information on the cathode ray tube screen of the television receiver again. , a detection means is provided to detect the status signal generated when switching from the television reception mode to the teletext reception mode that reproduces the above text and graphic information, and the output of this detection means is used to display the pre-switching status signal drawn before the channel selection operation. A teletext receiving device characterized in that it is configured to erase character and graphic information of a channel.