JPH0448312B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention utilizes the vertical blanking period of a video signal to transmit data in the form of a data packet whose unit length is a digital data signal superimposed on one horizontal scanning line period within that period. The present invention relates to a message display circuit for a teletext receiver that receives a teletext signal (a signal that transmits teletext data). (Prior art) On the display screen of a teletext receiver, various types of information such as weather forecasts, news summaries, and program introductions transmitted from broadcasting stations in the form of data packets are displayed in full fixed display, super fixed display, etc. It is now displayed in various display formats. The display screen that displays such information has a display area called a page header to inform the user of the reception status of the teletext receiver, and this display area contains the service system name, service system name, etc. as a page header text area. Page header text such as program number, page number, date and time is now displayed. The background color of this page header text area (page header background color) is colored in a color specified by a color code packet among several types of data packets. By the way, there are teletext receivers that can display messages such as "Please wait for a while" to "There is currently no teletext available" using built-in CPU processing, in addition to the page header text. In such a teletext receiver, the message is displayed in the same area as the page header text area, but when the message is displayed, the background color (message background color) is the same color as the page header background color. May be colored. However, if the message background color and the page header background color are the same color, it is difficult to determine whether the information displayed in the background color is a page header text or a message. (Objective of the Invention) An object of the present invention is to make it easier to distinguish between a page header text and a message displayed on a display screen by making the page header background color and the message background color different. . (Structure of the Invention) In order to achieve the above object, the present invention includes a character signal processing circuit built into a CPU that outputs a coloring signal corresponding to a page header background color using a color code packet in a data packet, and a character signal processing circuit that outputs a coloring signal corresponding to a page header background color using a color code packet in a data packet, and coloring in response to the coloring signal. a coloring detection circuit that outputs a detection signal; and a background color selection circuit that outputs a message background color signal of a color different from the page header background color in response to the coloring detection signal from the coloring detection circuit, and the background color The present invention is characterized in that the background color of the message displayed in the page header text display area is displayed in a color different from the page header background color by the selection circuit output. (Embodiment) FIG. 1 is a schematic circuit block diagram of main parts of a teletext receiver according to an embodiment of the present invention. The character signal received by this teletext receiver encodes the characters and figures of the information to be transmitted, and is transmitted in the form of data packets superimposed on the horizontal scanning line within the vertical blanking period of the television signal. It's something that comes. The code structure of these data packets and data blocks is described in detail in "Television Technology" (November 1985 issue) published by Denshi Gijutsu Publishing Co., Ltd., starting from page 19. The teletext receiver of the embodiment processes character signals transmitted in such a transmission format. In FIG. 1, reference numeral 1 denotes an input signal processing circuit to which a composite video signal obtained from a television signal received by a television antenna (not shown) is input. The input signal processing circuit 1 extracts and outputs a character signal from an input composite video signal, and processes the composite video signal by waveform equalization processing (processing the phase characteristics and frequency of the character signal to reduce waveform distortion). A waveform equalization circuit is used to flatten the characteristics (comprehensively flattening the characteristics), and a waveform equalization circuit is used to convert the vertical and
Synchronous regeneration circuits that generate gate pulses from horizontal synchronizing signals and regenerate clock signals, etc.
There are known code identification circuits and error correction circuits that extract character signals using gate pulses generated by a synchronous reproducing circuit, perform code identification at the timing of a clock signal, and extract digital data signals of "1" and "0". The circuit configuration is as follows. 2 is a character signal processing circuit including a CPU for decoding character signals extracted by the input signal processing circuit 1;
In relation to the CPU processing time, the character signal is once taken into the buffer memory, and the data contents are interpreted and processed by the built-in CPU according to the decoding processing procedure stored in the program ROM. It's getting old. Reference numeral 3 denotes a character generation ROM in which required pattern data is written in order to display codes corresponding to program data as characters, figures, etc., and this character generation ROM 3 responds to the processing code output from the character signal processing circuit 2. It is designed to output pattern data for character signals. 4 is message generation
ROM, and this message generation ROM4 is
Message pattern data is output in response to the processing code output from the character signal processing circuit 2. 5 is a coloring detection circuit 5; The character signal processing circuit 2 supplies a coloring signal corresponding to the page header background color to the coloring detection circuit 5 in accordance with the color code packet. The coloring detection circuit 5 is configured to output a coloring detection signal in response to this coloring signal. Reference numeral 6 denotes a background color selection circuit, and this background color selection circuit 6 is configured to output a message background color signal of a color different from the page header background color in response to the coloring detection signal. Each of these circuits 5 and 6 will be explained with reference to FIG. FIG. 2 is a detailed circuit diagram of the coloring detection circuit 5 and the background color selection circuit 6. In Figure 2, 5a, 5
b are a PACI detection circuit and a DB ₁₉ detection circuit, respectively, to which a processing code output including a data block is applied from the character signal processing circuit 2 via an input terminal 5c. The PACI detection circuit 5a detects the page data header (PACI) in the data block signal. The DB ₁₉ detection circuit 5b detects the data block.
Detect DB ₁₉ . 5d is a data block
This is an AND circuit that ANDs the output of the PACI detection circuit 5a and the output of the DB ₁₉ detection circuit 5b. 5e is
This is a shift register that shifts the output of the AND circuit 5d. Here, specify the page header background color for the data block containing the page data header (PACI).
Since this is done with the 4-bit binary high value of _b8 to _b5 of DB ₁₉ , the output of shift register 5e is b5 to _b5 .
A coloring detection signal, which is a signal corresponding to the page header background color, is output from _b8 . On the other hand, the background color selection circuit 6 is connected to the shift register 5.
It consists of inverters 6a, 6b, 6c, and 6d individually connected to each output _b5 to _b8 of e.
Therefore, each output _b5 to _b8 of the 4-bit binary configuration from the shift register 5e is inverted by the corresponding inverter 6a, 6b, 6c, 6d, and its inverted output 6a', 6b', 6c', 6d ' is output from the background color selection circuit 6 as a message background color signal. As a result, the message background color is specified to be different from the page header background color. The following table shows the structure of the page data header (PACI).

【table】

[Table] In this table, DB ₂ to DB ₈ are data group headers, and DB ₉ to DB ₁₉ are page data headers (PACI). Returning to FIG. 1, the message generation ROM 4 is as follows:
Message pattern data is output in response to the processing code output from the character signal processing circuit 2 and the message background color signal from the background color selection circuit 6. Reference numeral 7 denotes a display memory into which pattern data from the character generation ROM 3 and pattern data from the message generation ROM 4 are written in response to a write control signal from the character signal processing circuit 2.
The data written in the display memory 7 is read out by the display control circuit 8. 9, a page header sentence in response to the output data from the display control circuit 8;
This is a CRT display (the display screen of a teletext receiver) that displays messages, page header background colors, and message background colors. 10 is a keyboard for specifying a teletext program; 1
1 is a sound generation module that outputs sound data in response to data output from the character signal processing circuit 2;
12 is a speaker that operates in response to sound data from the sound generation module. In the embodiment having such a configuration, when the message generation ROM 4 is operated in response to the processing code output from the character signal processing circuit 2 and the message background color signal from the background color selection circuit 6, the message generation ROM 4 is operated in response to the processing code output from the character signal processing circuit 2 and the message background color signal from the background color selection circuit 6. , pattern data corresponding to the message and its background color (a color different from the page header background color) is written. Therefore, the CRT display 9 displays a message background color that is different from the page header background color. (Effects of the Invention) As is clear from the description of the embodiments, according to the present invention, the message background color is displayed in a color different from the page header background color, so that what is displayed on the screen is not a message. You can easily tell whether it is a page header text or a page header text based on its background color.

[Brief explanation of the drawing]

FIG. 1 is a schematic circuit block diagram of a teletext receiver according to an embodiment of the present invention, and FIG. 2 is a main circuit block diagram. 1 is an input signal processing circuit, 2 is a character signal processing circuit, 3 is a character generation ROM, and 4 is a message generation circuit.
ROM, 5 is a coloring detection circuit, 6 is a background color selection circuit, and 7 is a display memory.

Claims (1)

[Claims] 1. A character signal processing circuit built into a CPU that outputs a colored signal corresponding to a page header background color using a color code packet in a data packet, and a coloring detection circuit that outputs a coloring detection signal in response to the colored signal. , a background color selection circuit outputting a message background color signal of a color different from the page header background color in response to a coloring detection signal from the coloring detection circuit, and a background color selection circuit outputting a message background color signal of a color different from the page header background color, and a message background color signal of a color different from the page header background color in response to the coloring detection signal from the coloring detection circuit; A message display circuit for a teletext receiver, characterized in that a background color of a displayed message is displayed in a color different from a page header background color.