JPS5827591Y2 - Character signal receiving device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a character signal receiving device that selectively receives transmission signals of zero characters from multiple channels multiplexed on a television signal.

Among the teletext broadcasting systems, for example, the NHK f'')C system has nine types of teletext channels, and the transmission time for the - channel is about 2.5 seconds.

Therefore, it may take more than 20 seconds to wait from channel selection to display, and there is a drawback that the waiting time feels long to the viewer.

Therefore, a technique has already been proposed (Japanese Patent Application No. 52-104289 (see Japanese Patent Laid-Open No. 54-37527)) for displaying the title and page of the program being transmitted during the waiting time.

However, when displaying a desired program, it has become necessary to draw the attention of viewers by distinguishing it from the display during waiting time.

Therefore, in view of the above points, the present invention is a teletext receiving device that draws the user's attention by making the color of the characters such as the program title during the waiting time different from the color of the program title and display contents during the display time. This is what we would like to propose.

Before explaining the device of the present invention, NHK's C system and the prior art of displaying titles during waiting time will be explained.

First of all, NHK's C system consists of a total of 10 channels, including a channel that displays nine types of programs in text and graphics on the CRT screen, and a channel that superimposes flash news on the video being broadcast. , when displaying a full screen, one line of characters per field is composed of 18 scanning lines, 8 scanning lines are assigned between lines to display 8 lines of characters, and when displaying a figure,
The entire figure is displayed with 200 horizontal scanning lines, and when superimposed display is performed, two lines of characters are displayed at the bottom of the image.

Furthermore, the character signals are transmitted in a fixed order in units of one page of display on each channel, with the super display channel intervening.

Further, the multiplexing positions of the teletext signal are determined to be the 20th and 283rd horizontal scanning periods corresponding to the vertical blanking period,
Control signals and display signals are multiplexed in one horizontal scanning period.

The configuration of the control signal is a 4-bit STX signal for synchronization.
program code (PC), 3-bit program correction code (C
C), 8-bit scanning line code (LC), 1-bit parity check bit P, Ib1t subtitle erase pin) (
SE), and the subsequent display signal (C8) consists of 245 bits of information for one scanning line in the display area (see FIG. 1).

Furthermore, when transmitting character information, only the control signal and the display signal are multiplexed and transmitted in advance before transmitting each line, omitting the transmission of information between lines.

Therefore, it takes approximately 2.5 seconds to transmit text information, and 3.3 seconds to transmit image information.

In order to receive a character signal having the configuration as described above, a circuit as shown in the circuit block diagram of FIG. 2 is required.

That is, a waveform shaping circuit 1 that adjusts the waveform of a multiplexed signal for the video signal a, and a synchronization separation circuit 2 that derives a horizontal synchronization signal.
input to the burst sampling circuit 3 for deriving the burst signal;
A multiplex position detection circuit 4, which counts the synchronous separation outputs and detects the multiplexed position of character signals, controls the opening and closing of the signal sampling circuit 5 to derive a multiplexed signal d from the waveform shaping output C.

Of the derived multiplexed signals, the STX signal is input to the STX detection circuit 6, which receives the burst signal at the output e of the circuit and controls the phase of the clock generation circuit 7 which derives a clock f having a frequency 875 times the burst frequency. Then, the program code (PC) is input to the program code comparison circuit 8 and compared with the program code specified by the program selection switch 9, and the line code (LC) is input to the line code comparison circuit 10 and displayed. A comparison is made with the pit output of the horizontal line counter 11 that counts O at the 43rd H of the starting point, and the display signal (C8) is
is stored in the buffer memory 10 by the accumulation pulse g derived by the control circuit 12.

The stored 245-bit display signal (C8) is a transmission pulse g' derived from the control circuit 12 when the coincidence output of the line code comparison circuit 10 and the coincidence output of the program code comparison circuit 8 are derived simultaneously. The data is written into the main memory 15 via the rewrite gate 14 whose write path is opened by opening and closing outputs.

The main memory 15 cyclically shifts the stored contents via the rewriting gate 14, which is open on the circulation path side, by the shift pulse i derived by the control circuit 12 for display. It is input to the processing circuit 16.

Furthermore, the signal processing circuit 16 selects a color selection output j derived from the control circuit 12 in order to set the background to blue for full screen display and to set the background to normal video for super display. Color signals are selectively applied to the three cathode terminals via the drive circuit of A circuit 18 is provided, and when there is a change in the full-screen display program during the waiting time, the control circuit 12 causes the main memory 15 to store one line of display signals, and displays the program title and page. be.

Diagram number 19 in Fig. 2 is a stop circuit that fixes the display.
Reference numeral 20 indicates a channel display circuit of the selection switch 9, respectively.

In this embodiment, the color of the characters displayed during the waiting time and display time is changed in the above-described configuration. Specifically, the color of the characters displayed on the title and page during the waiting time is changed. The color is green, the title and page characters during the display time are red, the text and graphics from the second line onwards are yellow, and the superimposed characters are white.

The logic circuit to be added to the signal processing circuit and its circuit operation when changing the color of this embodiment will be described below with reference to FIG.

The symbol (FLH) in the figure is the title display terminal that is at high level in the display area of the first line of each field, (ER) is the period status detection terminal that is at high level during the period time, (AH) is the full-screen display channel selection (TV) is a teletext receiving terminal that becomes high level when receiving a teletext broadcast; (C8) is a character signal input terminal that inputs a character signal to be displayed from the main memory 15;
G and B are red, green, and red respectively in the drive circuit in front of the cathode ray tube.
Each output terminal is shown providing a blue signal output.

Note that input signals other than the character signal output are derived from the control circuit 12.

Therefore, in the case of full-screen display, the background color is made blue by the display format selection output, the first inverted output of the main memory output l, and the logical product output m, and when the time is selected, the time output n and the title display output are output. The main memory output l is derived to the G terminal by the logical product output p of 0, and the color of the title and page characters is green.When displayed, the logical product of the inverted output 1 of the period output n and the title display output 0 is used. Output q leads main memory output l to R terminal, changes the color of title and page characters to red, and inverts period output n to output 1 and title display output 0.
The main memory output l is derived to the G terminal and the R terminal by the logical product output r of the inverted output σ, and the color of the characters and figures that are the main text on the second line and below are displayed in yellow.

In addition, in the case of super display, when displaying, a character signal is derived from the inverted output of the display format selection output and the AND output S of the main memory output l to the B terminal, as well as the inverted output 1 of the period output n and the title display. The main memory output l is derived to the G terminal and the R terminal by the logical product output r of the inverted output 0 and the output 0, and the character color is set to white and superimposed on the image.

Therefore, in the case of full-screen display, green titles and pages can be displayed on blue during standby, and red titles and pages can be displayed on blue and yellow main text and graphics can be displayed during display.

Therefore, according to the present invention, it is possible to display the title and page being transmitted during the waiting period so that the user can confirm that the transmission period is in progress, and to alert the user by changing the color of the text when displaying the message. , the effect is dog.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the arrangement of character signals multiplexed in NHK's C system, Figure 2 is a schematic circuit block diagram of a character signal receiving device, and Figure 3 is an embodiment of the present invention. Each logic circuit of the signal processing circuit is revealed. Explanation of main figure numbers, 15...Main memory, 17
...CRT, l...Main memory output.

Claims (1)

[Scope of utility model registration request] When storing the character signal of a desired channel from the character signals of multiple channels multiplexed with the video signal in a storage means and displaying it on the television screen, the character signal of the desired channel is stored during the waiting time until the character signal of the desired channel is received. In a character signal receiving device that stores and displays only the character signals related to the title and page of a channel, and stores and displays the character signals of the desired channel at a display time after the character signals of the desired channel are transmitted,
A logic circuit is provided for selectively applying the readout output of the storage means to each cathode electrode of the cathode ray tube in order to make the color of the characters displayed during the standby time different from the color of the characters displayed during the display time. A character signal receiving device characterized by: