JPH01129680A - Teletext receiver - Google Patents

Abstract

PURPOSE:To improve the use of convenience by varying a longitudinal scroll speed in response to each mode so as to obtain a natural scroll speed. CONSTITUTION:A CPU 11 reads which mode of the normal and the high speed modes is commanded from a scroll speed command section 19 and sets a preset value in response to the mode to a filed counter 13. Every time a vertical synchronizing signal is supplied from a vertical sycronizing detection circuit 12, a preset value is counted down and when the count reaches zero, the signal of count '0' is given to the CPU 11. Thus, the scroll speed is made variable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a teletext receiving device, and more particularly to a teletext receiving device that receives a character signal superimposed within a vertical blanking period of a video signal.

(Conventional technology and its problems) Recently, a new broadcasting service, Teletext Broadcasting (hereinafter referred to as
teletext) has been put into practical use.

Unlike regular television programs that are organized by time, teletext repeatedly transmits various information and entertainment programs consisting of text, graphics, and additional sounds, allowing viewers to access the information they want when they want it. This is a new broadcasting system that has made it possible to

The above information such as text and images is multiplexed with pre-vision radio waves (television signals) from broadcasting stations that are currently being broadcast, and the recipient must have a receiving device or adapter that can receive teletext. Once prepared, you can select and enjoy your desired teletext program from among many teletext programs.

Also, this teletext signal (text signal bucket 1-) is
It is transmitted as a digital signal using the time gap (i.e., vertical blanking period) of the current preview signal, and the receiving device restores and converts the signal to display the image on the television screen. It is now possible to view teletext programs by generating additional sounds such as music. Furthermore, by adding a printer to the receiving device, it is also possible to record the contents of the teletext screen (Print 1~).

In the above-mentioned teletext broadcast, there is a vertical scroll display in which the screen is displayed flowing from the bottom to the top, but in the past, the scrolling speed was one line up every 6 fields as a matter of confirmation in "Operation". Since it was decided to scroll vertically in the direction, scrolling was performed only at this scroll speed.

However, in reality, depending on the content on the screen and the viewer,
There are problems in that the scrolling speed is sometimes too slow compared to the time it takes to read (the text on) the screen, and for programs with a large number of pages, it takes time to view all the pages.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional technology, it is an object of the present invention to provide a teletext receiving device that can vary the scrolling speed, provide a natural scrolling speed, and is easy to use.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a teletext receiving device that receives a character signal that is slightly heated during a vertical blanking period of a video signal. , a scroll speed instruction means for instructing a plurality of modes with different scroll speeds, a field number counting means for counting the number of fields, and a field period that differs depending on each mode instructed by the scroll speed instruction means. This invention provides a teletext receiving apparatus characterized in that it is provided with a control means for vertically scrolling one line at a time and controlling the vertical scrolling speed to be varied in accordance with each mode.

(Embodiment) An embodiment of the teletext receiver according to the present invention will be described below with reference to the drawings.

FIG. 2 is a block system diagram showing the configuration of an embodiment of the teletext receiver according to the present invention.

In the figure, a video signal obtained by selecting and demodulating a preview signal received by an antenna (not shown) is input from an input terminal 1, and is further input to a synchronization separation circuit 2 and a waveform equalization two-character signal separation circuit 3, respectively. Supplied.

The synchronization separation circuit 2 separates the vertical and horizontal synchronization signals and generates a goo pulse to extract the character signal, and supplies this to the waveform equalization character signal separation circuit 3. The signal is reproduced and supplied to the display clock generation circuit 4.

The clock signal is used for code identification of separated character signals and
- Used as a reference pulse for decoding processing in units.

Note that the display clock generation circuit 4 generates a display clock signal necessary for reading data from the display memory 5 based on the playback or [ ] check signal.

The display memory 5 includes a function memory 5a and a pattern memory 5b.
Then, the read data is D/A converted and converted into an analog RG.
Consists of color matrix 1 to color matrix 5C etc. for B signal,
Dots from character generator 6, RAM, etc.] -
Store pattern data. This driver L-pattern data is read out at the address data J from the display control circuit 7 and at the scanning period of the reraster.

Note that the functional memory 5a is a memory that stores the foreground color, background color, brushing, and concealing states. Also,
The pattern memory 5b is a memory that stores the shape of a pattern.

A character generator 6 decodes information such as literature and graphics, and generates pattern data such as characters and graphics to be displayed on the screen.

Further, the waveform equalization circuit of the waveform equalization single character signal separation circuit 3 shapes the waveform of the character signal in order to minimize or reduce errors in code identification due to waveform distortion during transmission. In addition, in the character signal separation circuit, after separating the character signal whose waveform has been equalized by the goo 1 to pulses generated in the synchronization separation circuit 2, code identification is performed at the timing of the clock signal, and the digital signals of rlj and rOJ are separated. The data paget is extracted in the form of .

The extracted data packets are subjected to error correction by the error correction circuit 8.

The program data corrected by the error correction circuit 8 is stored in the -dan buffer? RAM (Random Access Mem)
CP LJ (Central Process
The decoding process is performed by the Sssing Unit) 11.

The vertical synchronization detection circuit 12 detects a vertical synchronization signal (vertical retrace period) from the vertical and horizontal synchronization signals separated by the synchronization separation circuit 2, and supplies each signal to the field counter 13.

Others, work RAM 14. Remote control interface 15 and remote control transmitter 16. There is a printer interface 17 and a printer 18.

Next, the configuration of a main part of an embodiment of the present invention will be explained. FIG. 1 is a block system diagram that does not show the configuration of the main parts of an embodiment of the character number transmitting/receiving device according to the present invention. In addition,
In FIG. 1, the same components in FIG. 2 mentioned above are given the same numbers. Also, FIG. 5 shows a flowchart showing the operation of FIG. 1. - It is.

In FIG. 1, the scroll speed instruction section 19 (3L
1 remote control interface 15 and remote control transmitter 16
The system checks whether the viewer has instructed the scroll speed to be ``Normal Scroll 7'' or ``High Speed Scroll Mode,'' and then sends the instruction to the CPU.
Send to 11. For example, the instruction is given by pressing the "Normal Scroll" key or the "High Speed Scroll" key on the remote control transmitter 16.

The display control circuit 7 controls the display device (C) based on the contents of the functional memory 5a and pattern memory 5b that constitute the display memory 5.
RT) 20, and in particular, in order to realize scrolling, as shown in FIG. It has a function that allows data for an area corresponding to the screen to be displayed on the screen.

The display control circuit 7 includes a display start line register, in order to display the data of one continuous screen of the area of the display memory 5 (functional memory 5a) on one -7 screen. Display memory 5 (
Ij! ! Nometsu memory 5a in position is occupied
Then, the data in the display memory 5 (functional memory 5a) for one screen after that line can be displayed on the screen.

Therefore, it is possible to scroll the screen by increasing the line position written in the display start line register by 111 IT at regular time intervals.

4, in the display memory 5 (function memory 5a), write II I++ to the display start line register (
In particular, lines 1 to 204 are displayed on the screen. Also, when 2'' is written in the display start line register, lines 2 to 205 are displayed on both sides.By increasing the value written in the display start line register by 11111, both sides are scrolled.

Further, if the value flowing into the display start line register exceeds the total number of lines in the memory, scrolling can be continued by setting II I++ to the display start line.

The CPU 11 reads from the scroll speed instruction section 19 which mode of scroll speed ``Normal IZ11 High Speed'' is instructed.Then, the CPU 11 reads in the field counter 13 the values corresponding to the respective modes ``'Normal'' and ``Paper High Speed''. Set preset values.

For example, by setting the preset value to ++ 6 ++ in "normal scroll mode" and sr 3 pt in "high-speed scroll mode", Make it scroll twice as fast.

Further, the CPU 11 receives the signal of the count O'' from the field counter 13, and at this time writes a value to the display start register of the display control circuit 7 so that the display screen is shifted up by one line, for example. In the ``panoramic scroll mode'', vertical scrolling is performed one line at a time in a 3-field period, and in the ``panormal scroll mode'', one line is vertically scrolled in a 6-field period.At this time, the values of the field counter 13 are set again.

The vertical synchronization detection circuit 12 detects the vertical synchronization signal (vertical blanking period) of the television signal as described above, and supplies the detected vertical synchronization signal (vertical drive pulse) to the field counter 13.

The field counter 13 overrides the preset value according to instructions from the CPU 11. For example, for "Normal", the preset value is set to II 611, and for "High Speed", the preset value is set to "3".

Then, each time the vertical synchronization detection signal is supplied from the vertical synchronization detection circuit 12, as a result of counting down (-1) the above presera 1 value, the count value becomes 'O''. CP the count “O” signal when
Output to U11.

As described above, by vertically scrolling one line at a time in each group of field periods according to each mode in accordance with the instructions from the scroll speed instruction section 19,
Scroll speed can be varied.

Note that the scroll mode is not limited to the above two modes, ``Normal'' and ``Fast'', but also a mode slower than ``Normal'', a mode faster than ``High Speed'', or ``Normal'' and ``High Speed''. An intermediate mode may be set, and the preset value of the field counter 13 may be set appropriately for each mode.

In addition, the field counter is the RA in the CPU 11.
M may be substituted. Furthermore, regarding the detection of the vertical synchronization signal, the vertical synchronization signal may be inserted into an interrupt, and the count value 0'' may be detected during the interrupt processing.

(Effects of the Invention) As described above, according to the teletext receiving device of the present invention,
It has the advantage of being able to vary the scrolling speed, providing a natural scrolling speed, and improving usability.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram showing the configuration of the main part of the actual stream side of a teletext receiving device according to the present invention, and FIG. 2 is a block system diagram showing the configuration of an embodiment of the teletext receiving device according to the present invention. 3111 and 4 are diagrams for explaining the display memory, and FIG. 5 is a flowchart 1 showing the operation of the apparatus of the present invention. DESCRIPTION OF SYMBOLS 1...Input terminal, 2...Synchronization separation circuit, 3...Waveform equalization single character signal separation circuit, 4...Display clock generation circuit, 5...Display memory, 5a...Function memory , 5
b...Pattern memory, 7...Display control circuit, 10
...Program RAM, 11...CPU, 12...
・Vertical synchronization detection circuit, 13... field counter,
14... Work RAM, 15... Remote control interface, 16... Remote control transmitter, 19... Speed control instruction unit, 20... Display neck. functional memory

Claims (1)

[Claims] In a teletext receiving device that receives a character signal superimposed within a vertical blanking period of a video signal, by a predetermined operation,
Scroll speed instruction means for respectively instructing a plurality of modes with different scroll speeds; field number counting means for counting the number of fields; and one line in each different field period according to each mode instructed by the scroll speed instruction means. What is claimed is: 1. A teletext receiving device comprising: control means for vertically scrolling and controlling the vertical scrolling speed to be varied according to each mode.