JPS5974787A - Processing system of signal for multiplex character broadcast - Google Patents

Abstract

PURPOSE:To decrease the waiting time, by defining the area close to the highest and lowest stages of the scanning line of a picture signal as a character pattern code signal region respectively and sampling a character pattern code signal out of the picture signal to mix it with a character pattern signal obtained from the carrier wave of an audio signal. CONSTITUTION:A comparator 14 stores a code pattern equal to that of a character pattern start signal and performs matching of pattern with the signal supplied from an A/D converter 13 to deliver an output signal ''1'' when coincidence is obtained. Then a character pattern code signal 2 is delivered from the converter 13 via a gate circuit 17. When the reproduction is through with the signal 2 and a character pattern end signal 3 is received, a comparator 15 detects the code pattern of the signal 3 and delivers ''1''. Receiving this signal at a reset input terminal R, a switch circuit 16 closes the circuit 17 and opens a gate circuit 18 respectively. Thus a sound signal 1 following the signal 3 can be reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to multiplex text broadcasting (ETEXT) in a television system.

[Technical background of the invention and its problems]

Multiplex teletext (ETEXT) has already been put to practical use in Europe and has become widespread, and there has been a recent movement towards its practical use in Japan as well. The multiplex teletext broadcasting system proposed to date uses signals corresponding to two scanning lines controlled by image signals: a scanning line near the top that does not appear on the cathode ray tube, and a scanning line near the bottom. This method receives the signals as character pixel signals, stores them sequentially in a buffer memory, and displays them on a cathode ray tube when signals corresponding to 525 scans sK required for one screen are collected.

In this case, if there are more than 200 teletext broadcasts, the television system can form one frame of field image in 1/30 seconds.
Due to the nature of the system, it takes several seconds to display the screen after selecting a channel, and a considerable amount of time is required to obtain various information, which is inconvenient. A buffer memory with a large capacity is required to store the information, resulting in high costs.

[Purpose of abolishing Ming]

This invention was made in view of the above-mentioned circumstances, and its purpose is to reduce the waiting time from when a desired teletext broadcast is tuned until the character screen appears on the cathode ray tube, and the waiting time until the next character screen appears. An object of the present invention is to provide a teletext broadcasting data processing system that can be shortened.

[Summary of the invention]

The present invention, which has been made to achieve the above object, sequentially provides a character pattern code start signal, a character pattern code start signal, and a character pattern code end signal in a section where an audio signal does not exist on an audio signal carrier wave. By detecting the pattern code end signal, the switching circuit switches between the audio signal reproduction mode and the character pattern code signal reproduction mode, and the scanning lines near the top and bottom that do not appear on the cathode ray tube of the external image signal. The corresponding part is the character pattern code signal part and 7
．． c L. Signal processing for multiplex teletext broadcasting, characterized in that a character pattern code signal is extracted from this image signal and mixed with a character pattern code signal from the audio signal carrier wave to reproduce character information. It is a method.

[Embodiments of the invention]

This invention will be explained in detail below based on the embodiments shown in the drawings.

FIG. 1 schematically shows the contents of a signal in an audio signal carrier wave, and FIG. 2 is a block diagram of a reproducing apparatus.

In Figure 1, there is a normal audio signal (1) in the audio signal carrier wave VW sent from the transmitting side (broadcasting station), and there is also a normal audio signal (1) that does not matter if there is no audio signal ti+ or if the audio is interrupted for a short time. A character pattern code signal (
2), and before and after the character pattern code signal (2), a character pattern code start signal (3) and a character pattern code end signal (4) are arranged for the start and end of the character pattern code signal to be recognized by the playback device. ing.

The character pattern code signal (2) is digitally encoded in advance in a system with various characters and 4 turns, and is obtained by analog conversion of the code corresponding to the character nog turn to be sent. The pattern code start signal (3) consists of a special code that indicates that the character pattern code signal begins at that point, and the character turn code end signal (4) indicates that the character pattern code signal ends at that point. It consists of a special code that indicates the

Next, the playback device will be explained based on FIG.

The audio signal carrier wave VW as shown in FIG. 1 is received by an audio signal input device (11), sequentially subjected to detection, amplification, etc., and output. This output signal is immediately branched, one is input to the A/D converter (131), and the other (input to the gate circuit (181), A/D converter 03) converts this signal into digital. The digitally converted signal is further branched into three parts, one of which goes into the first comparison circuit (I41) which detects the character pattern code start signal, and the other one which detects the character pattern code end signal. The second comparison circuit +15HC is detected, and the other one is input to the gate circuit 1iJQ71.

The output signal of the first comparison circuit (14) is normally II (I
It is in the If state, and II I It is output only when the start signal is detected. It is connected to the set terminal S of the switching circuit (16) consisting of a flip-flop, and is connected to the second comparison circuit. ((The output signal of 51 is also normally I
It is in the I O11 state, and ++I II is output only when the end signal is detected, and is connected to the reset input terminal R of the switching circuit (161).From the positive output terminal Q of the switching circuit (16) The output signal of is the gate circuit (
The output signal from the interpolation tip Q becomes the input signal of the gate circuit (18). Positive output terminal Q
The output of is normally II OIf, and the set input terminal K
When 11111 is input, its output signal is II I
Instead of II, and the output to the interpolation tip is II I I
I becomes II O11, and that state is maintained. Furthermore, when 11111 is input to the input terminal R, the output of the positive output terminal Q is If 1 ++ to II (3I
I, and the output of the interpolation tip q is II g II
i)・et al+l I II and this state is maintained.

Gate circuits (17) and (18) are AND gates,
When the signal from each switching circuit (16) is 11111,
The gate circuit (18) which passes other input signals is connected to the speaker (25j), and the gate circuit (17) is connected to the mixing circuit (29).

On the other hand, the image signal input device (121 is a device that receives one image on the TV screen and performs detection, amplification, etc. Character pattern code signals are multiplexed at the broadcasting station in parts corresponding to predetermined scanning lines nearby.The scanning line sampling circuit (2η is equipped with a horizontal synchronization signal counter (scanning line counter), Only predetermined scanning lines provided with pattern code signals are extracted.

This scanning line extraction circuit (271) is connected to the A/D converter (28) and converted into a digital code signal, and further connected to the mixing circuit (291) to be mixed with the signal from the gate circuit (171).

The mixing circuit (29) is connected to the character pattern code buffer 09 to store the code signal, and this buffer (IO1 is connected to the character generator (20+V
The character generator (2o) outputs a character pattern signal corresponding to the code.

Furthermore, the switch (211 is a cathode ray tube (261)
This is a switch that allows you to display K teletext or normal TV. Connecting this switch to terminal C displays teletext, and connecting terminal P displays regular TV. Elephants can be played.

Next, the reproduction of teletext by the reproduction apparatus having such a configuration will be explained.

[Sound p] The signal received by the old IK signal input device is branched after being subjected to detection, amplification, etc., and one is directly connected to the gate circuit (18
1, and the other one is converted from an analog signal to a digital signal by an A/D converter.

The first comparison circuit (14) stores a code pattern that is the same as the code pattern of the character pattern code start signal, and performs pattern matching between this code pattern and the signal from the A/D'& converter 03: When the same code pattern is detected, the character pattern code starts, and the output signal from the output terminal is +10Il.
The signal changes from the state to "1" and is input to the set input terminal S of the switching circuit (16+) composed of flip-flops.

As a result, the output from the positive output terminal Q changes from If OIf to It I 11, the state of It I It is maintained, and the output signal from the complementary output terminal d changes to II I
The state changes from state 11 to state IfOn, and this state is maintained.

Therefore, in the gate circuit (II+, VC), the character pattern code start signal f31 K, which is digitally converted by the A/D converter (131), and the character pattern code signal (
2) can be output, and in the other gate circuit (18), the signal from the switching circuit (161) is II Dll, so A
The signals that do not pass through the /D converter ([3) are blocked, making it impossible to reproduce the audio.

Also, the reproduction of the character pattern code signal (2) is finished,
When the character pattern code end signal (3) is received, the second comparison circuit, circuit (1
At 51, the code pattern of the end signal is detected by pattern matching and outputted as +1111)2. This signal) k The switching circuit received at the IJ cent input terminal R (IO2
Then, the output signal from the positive output terminal Q becomes II I It to If oIt, and the output signal from the auxiliary output terminal Q becomes I
The signal changes from I Dll to II I II, thereby closing the gate circuit (17) and opening the other gate circuit (181), making it possible to reproduce the signal following the character pattern code end signal, that is, the audio signal (1).

In this way, the character pattern code start signal (3) and the character pattern code end signal (4) included in the audio signal transport gvw are detected, and when there is an audio signal, it is possible to automatically reproduce the audio signal, In the case of a pattern code signal, it is possible to switch to enable reproduction of the character pattern code signal.

On the other hand, the character pattern code signal sent on the part corresponding to the scanning &! of the retrace period of the image ``original signal'' is received by the image signal input device +121Vc, and then sent to the scanning line sampling circuit (
27) extracts only the scanning line with the character pattern code signal, and transfers this signal to A. The signal is converted into a digital signal by a /D converter (28) and sent to a mixing circuit (29).

The mixing circuit +2411 receives the character pattern code signal from the gate circuit (17+) and the character pattern code signal from the A/D converter, arranges them in a fixed order, and outputs them. Only when the character pattern code signal cannot be included in the signal carrier wave, if the character pattern code signal is included in part of the image [w signal, the character pattern code signal can be output from the mixing circuit (29) without confusion. be able to.

The character pattern code signal sent from the character pattern code variation (191 is a mixing circuit) is sent to the cathode ray tube (26
The code signals are sequentially stored until they reach a certain number that can be displayed in 1K, and when the number of stored code signals reaches a certain number, they are sent to the character generator (20), where the character pattern indicated by the code signal is generated. It is converted into information, and teletext can be displayed on a CRT.

In addition, switching between the image signal input device @ (I21 and the normal TV image is performed by the switch (211), but by connecting the switch cqi + v terminal C, the teletext screen can be changed from the switch C!! II to the terminal P. By connecting to the TV, a normal TV screen will appear on the Bunaran tube (2G).

〔Effect of the invention〕

As described above, according to the present invention, compared to conventional teletext broadcasting, the requested teletext can be displayed on the screen faster because the signal is encoded and sent using an audio signal carrier wave. In addition to sending coded character patterns, it also has a character generator for Japanese letters, Roman letters, numbers, etc., so the large buffer memory required to store pixel data as in the past can be eliminated. In addition, it has become easier for broadcasting stations to provide special news (subtitles) during regular broadcasts, and when it comes to videos, the special news characters, etc. It can also be viewed by erasing it.

Furthermore, each character pattern code is inserted into a portion of the image signal that corresponds to a scanning line that is not normally used, and this is mixed with the character pattern code signal from the audio signal and used for teletext broadcasting, making it possible to provide even more information. This increases the amount of teletext broadcasts and allows for faster (more) teletext broadcasts.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an explanatory diagram schematically showing the content of a signal in an audio signal carrier wave;
FIG. 2 is an explanatory diagram of the reproduction device. fi+...Audio signal (2)...Character pattern code start signal (4)...Character pattern code start signal (4)
...Character pattern code end signal (141...1st
Comparison circuit (15:...second comparison circuit 06)...Switching circuit (2)...Scanning line sampling circuit (291...Mixed circuit Patent applicant: Toppan Printing Co., Ltd. Representative Kazuo Suzuki)

Claims (1)

[Claims] A character pattern code start signal, character pattern code signal, character pattern code, and -end signal are sequentially provided in the section of the audio signal carrier wave where no audio signal exists, and switching is performed by detecting the character pattern code start signal and the character pattern code end signal. The circuit switches between the audio signal reproduction mode and the character pattern code signal reproduction mode, and on the other side, the parts corresponding to the scanning lines near the top and bottom that do not appear on the cathode ray tube of the one-image signal are used as the character pattern code signal area. A signal processing method for multiplex teletext broadcasting in which a character pattern code signal is extracted from this image signal and mixed with a character pattern code signal from the audio signal carrier wave to reproduce character information.