JPS58108884A - Character signal generation and processing system of character broadcast signal generator - Google Patents

Abstract

PURPOSE:To save memory, to a modify the contents of transmission easily, and to reduce the size of a system by storing only the information data contents of each data packet in the character memory in a signal generation part and adding a discrimination control code in a program when transmitting a character signal. CONSTITUTION:A color code is read out of an address of the character memory 6 as specified by a program number set by a page control packet, and a discrimination control code is added to it to obtain a color code packet (CCP- A, B), which is transferred to buffer memory 4. A pattern data packet (PDP) is also transferred to the buffer memory 4 similarly by reading pattern data out of a specified character memory address and then adding a discrimination control code as well. A character signal generated by a character symbol generation part 1 is superposed by a signal mixing part 18 upon a color bar signal obtained form an internal color bar generator 19 through a switch 20, or a video signal obtained from an external input terminal 21 through the switch 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teletext signal generator for multiplexing and transmitting characters, graphics, etc. during the vertical retrace period of a television signal, and in particular, the present invention relates to a character signal generation processing method thereof. In particular, only the information data contents of each data packet such as color code packets, pattern data packets, horizontal scroll data packets, etc. excluding page control packets are stored in the character memory inside the signal generator, and are stored in the program when sending character signals. By adopting a method of adding an identification control code to a teletext signal generator, the aim is to save memory, easily change the transmitted content, and downsize the system.〇Commonly used teletext signal generator , the character data stored inside it is stored in the form of a data packet consisting of an identification control code and information data as shown in Figure 1. Because the data is stored repeatedly, it requires a fairly large amount of memory.Also, when changing part of the data stored in memory, the processing operation becomes complicated. .

The present invention has been made in view of the above points, and instead of using the conventional character data storage method in a character signal generator, it uses identification control codes and screens that repeatedly transmit the same data. Overall f: A control page control packet is added within the program to provide a character signal generation processing method that saves memory and simplifies information editing.

The present invention will be described below with reference to embodiments shown in the drawings. Second
The figure shows a Pronk diagram of one embodiment of the teletext signal generator according to the present invention, and FIG. 3 vi shows a flowchart of the signal processing operation of the same embodiment.

Here, in order to generate a character signal to be sent out, signal processing is first performed in the character signal generating section 1. This character signal generating section 1 is composed of a hard address counter 2, an address bus switching section 3, a buffer memory 4, a character signal control section 5, a character memory 6, and a parallel-serial shift register 7, and its signal processing operation is performed by a third The procedure is as shown in the flowchart in the figure. This operation is performed by the horizontal synchronizing signal H-D sent from the synchronizing signal generating section 8 to the character signal controlling section 5.
2IH (H is a horizontal constant scanning line) starts from the end 5th time point.

First, set what program to send, and then set page control bag (PCP) data depending on the program, and transfer it to back 1 memory 4. Next, set page control bag from character memory 6. The color code is read from the address specified by the program number, an identification control code is added to it, and the color code packet +- (CCP-A
, B) to the buffer memory 4. Similarly, the pattern data packet (I) DP) is read from the specified character memory address, and the identification code is added to it and stored in the buffer memory 4.
will be forwarded to. Yet another horizontal scrolling data packet
Similarly, for (HDP), an identification control code is added to the pattern data read out from the character memory 6 and transferred to the buffer memory 4. Note that the buffer memory 4 may have a capacity of 2H (that is, 37×2=74 bytes), but a capacity of 4H is provided in consideration of future expansion. A character signal is generated by the signal processing operation of the character signal generating section 1 as described above, and is stored in the buffer 4.

On the other hand, a multi-gate generating section 11 consisting of an H counter 9 and a gate generator 1o, and a superimposition rib position determining section I4 consisting of two frequency dividers 12 and 13,
It generates the sending timing for sending out the character data stored in the .

In particular, this multiple gate generating section 11 generates a gate signal that determines character signal superimposition H (multiple H) during the vertical blanking period, and the position of multiple H can be arbitrarily set by an internal dino switch. In addition, in the heavy blue vertical position determination unit 14, the frequency of 14.818 MHz sent from the synchronization signal generation unit 5 is
The superimposition timing is determined from which position in the multiplex H to start superimposition by counting 64 clocks. For example, this superimposition position is set at a position 9,78±0,35 μS from the starting position S of the television horizontal synchronizing signal, as shown in FIG. When the superimposition timing is determined, the character data stored in the buffer memory 4 in units of 8 bits is converted into serial data by the parallel-serial/ft register 7 and sent out from that position. The transmission clock at this time is 5.73MHz, but this clock is 14.3MHz.
18MHz is multiplied by 2 in the multiplier 16 in the clock generator 15.
The signal is multiplied and then passed through a frequency divider 17 to be divided by five to generate the signal. In this way, 2 H per field
data packets are sent out.

The character signal generated by the character signal generating section 1 is obtained from the internal color bar generator 19 via the switch 20 in the signal mixing section 18, and a multi-color bar signal is obtained from the external input terminal 21 via the switch 20. At this time, the multiplexed video signal obtained from the mixing 6+g is directly output from the video signal output terminal 22, while it is modulated by the RF modulation section 23 and then converted into an RF multiplied signal and sent to the RF output terminal 24. is output from.

According to the character signal generation processing method of the present invention, as described above, fixed information such as identification control codes and page control packets that control the entire screen are added within the program when sent from the character signal generation section, and are added to the character memory. Since only information data such as patterns and colors are stored in the , it is possible to greatly reduce the memory capacity, and it is also easy to change the transmission contents. Furthermore, since the memory capacity is relatively small in this case, there is no need for large-capacity storage devices such as proppy disks, and RO
A wide variety of programs can be transmitted with just a few semiconductor memories like M, and the teletext signal generator itself can be miniaturized, and there are no restrictions on installation or transportation.

[Brief explanation of the drawing]

FIG. 1 is a data packet configuration diagram showing the contents of data sent by a teletext signal generator, FIG. 2 is a block diagram of the teletext signal generator according to the present invention, and FIG. 3 is a character signal generation process according to the present invention. A flowchart showing an example of the method, and FIG. 4 is a signal waveform diagram for explaining the operation of the method. l...Character signal generation section, 4...Buffer memory, 5
...Character signal control section, 6..Character memory. Agent Patent Attorney Aihiko Fukushi

Claims (1)

[Claims] 1. In a teletext signal generator for multiplexing and transmitting characters and graphics during the vertical retrace period of a television signal,
Only character information data such as patterns and colors is stored in the character memory in advance, and when the character information is read from this character memory and sent out, fixed information such as identification control codes and page control packets are added by a program and sent out. A character signal generation processing method in a teletext signal generator, characterized in that: