JPS59224988A - Character broadcast receiver - Google Patents

Abstract

PURPOSE:To display a character broadcast pattern on a TV screen together with a TV broadcast pattern by providing a key for mixing and operating this key input. CONSTITUTION:A remote control signal generated by the key operation of a remote control device is given to a CPU13 via a decoder 11 and an I/O port 12. Then the CPU13 discriminates which key is operated from the content of the remote control signal. Further, when it is discriminated that the mix key is operated, a character data signal is applied to a CRT10 via an R, G, B control section 8. Thus the character broadcast pattern is displayed on the TV pattern together with the TV broadcast pattern.

Description

[Detailed Description of the Invention] Technical Field> The present invention utilizes the vertical blanking period of a television (TV) video signal to detect characters transmitted by data packets whose unit length is the horizontal scanning period. The present invention relates to a teletext receiver that receives signals, and particularly to mixing a teletext screen with a TV broadcast screen.

<Prior art> Such a teletext receiver is generally a television receiver (which is equipped with a teletext decoder, and is capable of displaying ``■''■ broadcasts alone or teletexts alone) on the TV screen. Or, there are some that are made to be displayed at the bottom of the TV screen on the transmitting side.

However, in order to be able to display both TV and text broadcasts at the same time (there is no problem), if the sending side specifies super mode with both the background color and text color black, the TV
There are some that lower the brightness of the screen to make it easier to see the text. However, when the receiver mixes teletext and TV broadcasts, unless the brightness of the TV screen is lowered, the text will not be displayed.
It may be difficult to see on the V screen.

<Purpose> The third object of the present invention is to provide a "mix" key and to make it easier to see characters on the TV screen when this key is input.

<Embodiment> Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

FIG. 1 is an overall circuit diagram of this embodiment.

The teletext receiver of this embodiment includes a television antenna (not shown), a receiving section that performs processing such as RF amplification, IF amplification, and detection on the television signal, and a text signal receiving section that extracts a text data signal from the output of the receiving section. The character data signal, which is multiplexed and transmitted on the radio waves containing the standard television signal, is transmitted from this character signal receiving part to the first
The serial/parallel converter 1 shown in the figure converts a serial signal into a parallel signal. This teletext receiver also includes a remote control device for remotely controlling the teletext receiver, and can be operated by manual operation of various keys provided on the remote control device, which will be described later. The remote control signal from this remote control device is
The signal is supplied to the decoder 11 in FIG. 1 and decoded for processing. In FIG. 1, 2 is a video RAM control section, 3 is an address switching section, 4 fj: pattern RAM, 5
is a color RAM. A video RAM is constructed from both RAMs 4.5+. 6 is a parallel/serial converter,
7 is a color control section, 8 is an R (red), G (green), B (blue) control section, 9 is an output signal conversion section, 101'j: CRT
.

12 is I10 port, 13 is CPU, i4.15°16
(l″j: system control line buffer, address buffer, data path buffer, 17F1 basic clock generation unit that generates the basic clock, 18 data bus, 1
9fd address bus; 20 a program/character ROM in which programs and characters for instructing the operation of the CPU 13 are stored; and 21 a working RAM used by the CPU 3 for operation.

22Vi memory control register, 23 multi-memory, 2
4 is a system control line.

FIG. 2 is a circuit diagram of a main part of the embodiment specifically showing a part of each of the color RA, M 5 , color control section 7, and R, G, B control section 8 shown in FIG.

In Figure 2, 100r! Background color: red (BR), green (
BG), the background color signal of blue (BB) and the text color are the same red (
FR), green (FG), and blue (FB) character color signals; 101 is a color data buffer;
02 compares the text color signal and the background color signal, and only when the composite colors of the text color and background color match, a low level signal (hereinafter, low level signal is 0, high level signal is 1) A comparator circuit 103fl outputs a signal S and M/T of 0 and 1 as shown in the following truth table. 104,105.10
6 is the first. 2nd and 3rd NAND gates, 107 is NOR
The gate 108 is an AND gate and a 109Vi inverter.

The M/T and S signals from the I10 port 103 are generated by one manual key operation of the remote control device. That is, the remote control signal generated by one manual key operation of the remote control device is sent to the CPU 13 via the decoder 11 and I10 port 12.
given to. cpul3 determines which key was input from the contents of this remote control signal,
k.

G, B, I10 port of control unit 8, i.e. I1 in FIG.
0 port 103. Thus, I10 port 1
The above-mentioned M/T signal and S signal are generated from 03.

Truth table〉 In this truth table, “T■” means TV broadcasting alone.
"Character" indicates the key power required to display the screen, "Character" indicates the key power required to display the TV screen with teletext alone, and "Super" indicates the key power required to display the TV screen when the transmitter is in super mode.
This shows the key human power required to display the V screen in this super mode. "Mix" means that when the transmitting side is sending only teletext, the receiving side mixes this teletext at the same time as the TV broadcast and displays the TV screen. Indicates the key human power to display. Therefore, when 1-TVJ's key human power is I
10 port 103 with 0” M/T signal and /J O/
Outputs the S signal of /, and presses 71 when the key for "character" is manually operated.
Outputs the M/T signal of “0” and the S signal of 0, and “Super”
Outputs the M/T signal of 70" and the S signal of "1", and the key of "Mix" is pressed //]
The M/T signal of // and the S signal of '勺' are output. In this embodiment, the output signal of the NOR gate 107 is used as the brightness reduction signal, and the output signal of the AND gate 108 is used as the mute signal. Assume that the brightness lowering signal is transmitted either by the receiver operating the "Mix" input key to specify mix mode for each TV broadcast and teletext screen, or by setting the background color to black on the transmitting side. This is to lower the brightness of the TV screen to prevent the text from becoming difficult to see on the TV screen when the text color is black and super mode is specified. This brightness reduction signal is applied to the brightness signal input terminal of the CRTiQ via the output conversion circuit 9. A color memory 100, a color data buffer 101, a comparison circuit 102, a first NAND gate 104, and an inverter 109 are circuits for detecting that the background color is black and the text color is black or faded on the transmitting side. That is, when the background color is black, the background color signals BR, BG of the color memory 100
, BB are all // O // signals,
Therefore, the output of the first NAND gate 104 at this time is (, 1// 1 //. Also, when the text color is black, the text color signal FR of the color memory 100.

Both FC and FB become signals of /L Q //, so the comparison circuit 102 derives an output of // 01/ from the background color signal and character color signal, which are all //Q I/. Also, since the transmitting side is in super mode, the I10 port 103 derives the S signal of 〃]'' from the truth table. Therefore, all three inputs of the second NAND 105 are given signals of 1, and the NOk gate 1
A brightness reduction signal of 07V'i"1" is output. On the other hand, when the "Mix" key is manually operated on the receiver side, as shown in the truth table, the M
/T signal and S signal of 71'' are given to the third NAND gate 1-106. As a result, the third NAND gate 106 outputs the signal of 〃o'', so the brightness reduction signal of NOR game 107ba〃1〃 Output.

On the other hand, the mute signal is used to cut the audio when a single character key is manually operated.

It is clear from the truth table that when there is a "character" key, the M/T of number I10 port 103 to n 1 n
The signal and the S signal of 0'' can be output. Both signals are output from the 3rd NA.
ND gate 1061 is applied, and 3N8N I) gate 106 outputs a signal of 1". Therefore, AND
As a result, the gate 108 outputs a mute signal of ']' since the signals of the same number "1" are applied to both input sections.

Therefore, according to this embodiment, when the transmitting side specifies the super mode with the background color and one character color both black, if the "super" input key is operated, a brightness reduction signal is generated. However, if the receiver operates the "Mix" input key while the transmitter is transmitting teletext, a brightness reduction signal is generated and the text is displayed.
゛V It can be made easier to see on the screen.

<Effects> As described above, according to the present invention, even when the "Mix" input key is operated, a brightness reduction signal is generated to lower the brightness of the TV screen. The characters displayed on the TV screen become very easy to see.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is an overall circuit diagram of a teletext receiver according to the Ninko C embodiment, and FIG. 2 is a circuit diagram of essential parts of the teletext receiver. 100...Color memory, 1Q1...Color data buffer, 102...Comparison circuit, 103...I10
Port, 104, 105, 106... 1st. Second. 3rd NAND Gut, 107...
NOR Gut, 108...AND gate. Applicant Sharp Corporation Agent Patent Attorney Kazuhide Okada

Claims (1)

[Claims] ([) A teletext receiver capable of manually operating a "mix" key for mixing a teletext screen with a TV broadcast screen and displaying the same number on the TV screen. (2) Equipped with a "mix" key for co-mixing the teletext screen with the TV broadcast screen and displaying it on the TV screen, and adjusts the brightness of the TV screen in response to the input operation of this key. A teletext receiver comprising means for generating a brightness reduction signal.