JPS58157277A - Receiver for character broadcasting - Google Patents

Abstract

PURPOSE:To process data through reading the content of a code and to attain accurate still picture processing, by writing the code which does not contained in a still picture signal or the code which is not subject to the effect of the composition processing of the still picture such as a dummy packet, in a buffer memory storing the still picture temporarily. CONSTITUTION:A video signal amplfied and detected at a video IF amplifier circuit 3 is amplified at a video amplifier circuit 4 and a picture is displayed on a CRT5 via an output interface 5. The still picture in a video signal is picked up at a pickup circuit 6, stored once in a buffer memory 7, and the data is processed in one field period with a CPU8. When the data is coincident with the program and page selected at a still picture program selector 11, one screen of the still picture is stored in pattern and color memories 12, 13. In storing the still picture in a memory 7 temporarily, a code which is not included in the still picture signal or a code which is not giving the effect on the composition of the still picture such as the dummy packet is written in the memory 7, allowing to prevent the error in reading the content of the memory 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention receives still image signals such as characters and figures that are superimposed on normal video signals during the vertical blanking period of a television signal, and processes the signals using a central processing unit such as a microprocessor. The purpose of this invention is to provide accurate operation regarding a device that processes data, stores it, reads it out, and displays a still image.

The four still image signals Ji+ that are superimposed on the video signal and sent out have, for example, the following format. That is, on the transmitting side, horizontal 148 bits, vertical 104 lines, total number of pixels is 48X.
A pattern signal decomposed into matrix-like pixels of 104-50591 bits, 81 horizontal blocks of the above pixel (8 bits horizontally, 96 bits total of 1 m vertical line), color signals of 17 vertical stages, each of the above still image signals. 1148 bits for horizontal line C pattern signal, 8 bits for color signal
1 block) in the vertical blanking period.
It is sent out with various control codes added during an arbitrary period from 1711th (1711th) to 2nd (184th).

Types of autopsy codes to be added include, for example, a start signal (CR), a 7-raming code (FC), a service identification 7 cut (Nikko/Eng.N), and a data identification (D-Eng.).

At the same time, a still image is composed of multiple programs and pages, and data packets (PO
P) is also sent out prior to the above pattern signal and color signal packets, and this POP also receives the above control signals (start signal (CR), 7-raming code 1'' (CR), service identification/interrupt (8-man AN ), data identification (DI) is added.

On the other hand, on the television receiver side, for example, in the system shown in FIG. 1, the still image signal superimposed on the television signal is separated, demodulated, and displayed on the screen. That is, in FIG. 1, a television signal received by antenna +11 and superimposed with a still image signal is selectively amplified by a desired channel by a tuner (2), converted to a video intermediate frequency, and then sent to a video intermediate frequency amplification circuit (3). ), the signal is amplified and detected, converted into a video signal, and guided to the video amplification circuit (4). Then, a normal television image will be displayed as you drive through the Prakun tube.

On the other hand, the video signal on which the still image signal has been superimposed is supplied to the extracting circuit tel, where the still image signal is separated from the normal television signal and once stored in a buffer memory (7).

This stored data is processed by a central processing unit (hereinafter abbreviated as OPu) (8) such as a microprocessor within the l field period.

If the program and page selected with the program selection device (++) are the same as the data stored in the buffer memory (7), the pass line is added to the pattern memory core and color memory +13+ for display on the TV screen. α・
Transferred and stored via. It consists of a path line (a data bus that transfers 91Vi data, address information that determines the address information of memory and input/output devices, and a control path that controls these).

The above transfer memory is for one still image (e.g. 804947 minutes)
By repeating this process until , pattern memory H and color memo IJ-(l [information for one selected still image are accumulated. Then, pattern memory 〇no and color memory Ql are synchronized with the scanning of the color television. The readout control circuit sequentially reads out the stored contents, and outputs them to the Plaquen tube (l) via the output interface circuit (6).
If supplied to @, the still image will be displayed on the television screen.

ROM (9) is CPU u (
Read-only memo IJ- that stores 81 processing procedures
RAM Ill is a glue write memory for temporarily storing and storing data when 0Pu (8) performs the above processing. Here buffer memory (7)
is the bit rate C of the still image signal being sent out, for example 6
．． 7S hits/sec) is much faster than the data processing speed of OP u f8), so once the above Pan 7Armemo I+-+
This is to store one packet worth of still image signals in the 7+ and process the stored contents one after another as needed during one field period until the next new still image signal arrives.

The present invention attempts to perform accurate operation even when a still image signal changes from a superimposed channel to a non-superimposed channel during a vertical blanking period, or when still image signal superimposition stops. It is. This will be explained in detail below.

Figure 2 shows the structure of the still image signal (data packet), including page control bucket (POP), color code packet (CAP), and pattern data packet (FDP).
, horizontal scrolling packet (HDP).

Program index packet (P), dummy packet (DMP)
) There are 6 types in total. Each of these packets has a control section (part of a header) at the beginning.

To write to the buffer memory (7) in Figure 1, for example, synchronize the extraction using the clock run-in (OR) and 7 Raming Code (PC) in Figure 3, and then write subsequent data to the buffer memory. I am writing.

Here, if you change from channel C tuner) on which a still image signal is superimposed to another channel on which a still image signal is not superimposed, the contents of the buffer memory in Figure 1 remain stored and the still image is Even if a channel is not superimposed, it is incorrectly determined that it is superimposed, and accurate operation cannot be performed.

In view of this situation, the present invention writes code F, which is not included in the still image signal, into the buffer memory (7) in Fig. 1.
Alternatively, a code that is not affected by the process of assembling a still image, such as the dummy packet (DMP) shown in Figure 8, is written into the buffer memory (7) to enable more accurate operation. be.

To process a still image signal, for example, OP u in FIG.
(8) reads the data in the buffer memory (7) and assembles the still image manually.
Correct operation can be performed by rewriting the contents of . Here, the lick code for the still image signal mentioned above will be explained below.

For example, check bits as shown in Figure 3 are added to all check codes except for the clock run-in (OR) and 7 lemming code (FC) of the still image signal C data packet in Figure 3. 1 when check bit is added
Even a bit error can be corrected. Since a code with a 1-bit error can also be used as a still image signal, the number of combinations is 9 if even a 1-bit error becomes true data for al in Figure 8. Combination 4ILLl~I! L
] For j, there are 9×16 combinations of rooster and 0. However, from Figure 8, 8 bits allow 9 combinations of 6 windows and 111 dollars, resulting in 256-144-111 codes that are impossible for a still image signal.

The processing sequence of □ p u f8) in Figure 1, which writes any one of 111 codes that cannot be used as control codes for still image signals, to the buffer memory, reads and processes the contents of the buffer memory, and processes it as a still image signal. If there is a code that cannot be found in the control code, correct operation can be achieved by not processing the entire packet.

[Brief explanation of the drawing]

FIG. 1 is a still image receiving system diagram of the present invention, FIG. 3 is an IT diagram of a still image signal (data packet), and FIG. 8 is a bit configuration diagram of a Hamming code of the present invention. 141F! Video amplification, (6) is output interface,
(6) is extraction circuit% (7) is buffer memory,
(8) is the central processing unit (CPu), (9) is the program storage ROM, tlσ data RAM, (Kawake → Display program selection device, (12 is the pattern memory, 03Vi
Color memory, 0 moan is a pass line. Agent Shin Kuzuno - Figure 1, Figure 2

Claims (1)

[Claims] Buffer memory temporarily stores still image signals.
Teletext reception is characterized in that accurate operations are performed by an external device writing a code that is not included in the IIJa code of the still image signal, or a code that may be a control code but does not affect the process of assembling still images. Machine.