JPS6150554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a teletext receiver (hereinafter referred to as receiver) for teletext multiplex broadcasting.

In teletext broadcasting, text (including symbols, figures, etc.) information is multiplexed and transmitted in a time-division manner during the vertical blanking period (hereinafter referred to as VBLK) of a television signal (hereinafter referred to as TV signal), and the receiving side Text information is extracted from a TV signal, stored in a memory, and then read out continuously from the memory and displayed.

Generally, when receiving teletext, first select (select) the broadcasting station that is transmitting teletext, then select the teletext program (hereinafter referred to as "text program") using a keyboard, etc., and watch the desired teletext program. Receive. Another method is to display text programs continuously without specifying a specific text program using the keyboard after tuning, and select a desired program from among them. exactly,
It is similar to when watching TV, instead of looking at the program contents in a newspaper or the like and then selecting a channel, you rotate through the channels at random and stop at the desired channel. This latter selection method is something everyone should do.
This may be more common.

In the case of selecting a text program, if the desired text program is not available on one broadcast station, the user must turn to another channel, select another broadcast station, and then select a text program again. In this case, it is troublesome and inconvenient to select the channel each time.

For those who watch teletext programs, there are cases where they treat teletext as one thing and treat it the same way as if the number of broadcast stations had increased by one.

In view of this point, the present invention provides a teletext receiver with good operability.

That is, the present invention provides a text receiver that allows the receiver to automatically select channels and watch text programs continuously without having to perform the above-mentioned channel selection each time, and that can stop at a desired program. It is.

To explain in more detail, the text programs of one broadcasting station are displayed one after another, and when all the programs of that station have finished being displayed, the program automatically switches to the adjacent broadcasting station. The feature is that the text programs are displayed consecutively in the same way as before, and the following stations are automatically selected, and when all the stations have been selected, the program returns to the first station. Therefore, in the process of automatic channel selection, when a text program desired by the operator is reached, the desired text program can be selected by switching to a state where the text program remains unchanged.

Hereinafter, the receiver of the present invention will be explained in detail.

FIG. 1 shows a block diagram of an embodiment of the receiver of the present invention, and FIG. 2 shows a block diagram of the same portion.

Prior to explaining the characteristic parts of the present invention, the general functional parts of a receiver will be explained.

A TV signal inputted from the TV antenna 1 is inputted to the tuner 2, and the channel is selected (the TV channel selection key and a series of keys, switches, etc. related to the TV are not shown).
After being amplified by high frequency, it is guided to IF and DET 3 where it is amplified by intermediate frequency and image detected, and further guided to character signal extraction gate 4 and synchronous separation circuit 12.

At the character signal sampling gate 4, the video signal was detected.
The character information multiplexed on the VBLK of the TV signal is gated and extracted character information is led to the buffer memory 5. Character signal extraction gate 4 and buffer memory 5
is controlled by the output S of the decoder and control signal generation circuit 13. The signal S is a signal that can stop the reading of the gate 4 or buffer memory 5 during multiple horizontal periods of V BLK (hereinafter referred to as multiple H) as required. The program number of a text program is input using the normal operation keys and the operation keys of the display 18, and the decoder and control signal generation circuit 13 detects through decoding processing that this program number and the program code read from the buffer memory 5 match. At this time, the contents of buffer memory 5 are input to pattern memory 15 or color memory 16.

The pattern memory 15 is composed of RAM and can store pattern information for one screen (one page) of display. The color memory 16 is similar to the pattern memory 15 and stores color information necessary for one screen. The memory addresses of these memories 15 and 16 are obtained from the address counter 14, and the pattern information and memory information of these memories 1
This data can be obtained both by writing into the memories 15 and 16 and by reading from the memories 15 and 16.

The bit synchronization signal detection circuit 9 is a clock signal generator 1 which is multiplexed with a part of the multiplexed signal to be sent out.
Enter 0.

This clock signal generator 10 generates a clock for writing character information into the buffer memory 5, pattern memory 15, and color memory 16. Note that the frame synchronization signal detection circuit 11 is
The timing of writing character information to the buffer memory 5 is controlled.

The clock signal generator 10 also functions as a reading clock for continuously reading character information from the pattern memory 15 and color memory 16 and displaying it on a television's cathode ray tube or other display (not shown). Occur. This reading clock is synchronized by a horizontal synchronizing signal (hereinafter referred to as H pulse), and a timing signal for achieving this synchronization is obtained from the decoder and control signal generating circuit 13.

The decoder and control signal generation circuit 13 receives the vertical synchronization signal (hereinafter referred to as V pulse) H pulse from the synchronization separation circuit 12 and generates various timing signals. or read and decode various control signals, such as program numbers, from the buffer memory 5 to generate command signals at the appropriate time.

Now, after selecting the desired station, if you input the number of the desired text program using the operation keys and the operation keys on the display section 18,
When the decoding and control signal generation circuit 13 detects a match between this program number and the program code read from the buffer memory 5, the decoding and control signal generation circuit 13 obtains the necessary timing signal and the contents of the buffer memory 5 (character information ) is input to the pattern memory 15 or color memory 16 and stored therein, and furthermore, character information is continuously read out from the pattern memory 15 or color memory 16, passes through the mixing circuit 17, and is displayed on a cathode ray tube or the like.

Note that the mixing circuit 17 receives pattern information and color information as input and generates R, G, and B signals.

The above is a description of the character receiving function part of the character receiver, which is already a well-known circuit.

Next, an embodiment of the present invention in which a functional part that enables automatic channel selection is added to this functional part will be described.

The teletext detection circuit 7 inputs the character information in the buffer memory 5 and determines whether or not there is character information in the buffer memory 5. If there is no character information, it also outputs a pulse. This function is useful for skipping a TV channel if teletext is not being transmitted when the channel is switched.

The character program comparison circuit 8 receives the program code from the buffer memory 5, stores the first program code, and then compares the program code input for each field with the former, and if they match, it changes the program code in other words. For example, when a text program completes one cycle on the channel being received, an output pulse is output. Note that the storage and comparison of program codes is executed in the page header control line (information that comes at the beginning of each character program).
Control signals are inputted to the teletext detection circuit 7 and the teletext program comparison circuit 8 from the decoder 13 and the control signal generation circuit 13, and the above operations are performed based on commands from the operation keys and the operation keys on the display section 18. Execute. That is, the operation keys and display section 18 have the following information:
A selection mode key is provided for setting automatic channel selection, and when this selection mode key is operated to set the selection mode, the decoder and control signal generation circuit 13 uses a control signal to control the character sending detection circuit 7 and character transmission. The program comparison circuit 8 is controlled to the above operating state. During normal character reception, which is not in this selection mode, the teletext detection circuit 7 and the character program comparison circuit 8 do not perform the above operations.

When the channel selection circuit 6 receives pulses that are the outputs of the teletext detection circuit 7 and the teletext program comparison circuit 8, it switches the receiving channel. For example, when one pulse is input, one channel is switched.

FIG. 2 shows a block diagram of one embodiment of the tuning circuit 6. As shown in FIG.

The tuning circuit 6 is composed of a channel switch IC (for example, the Texas 1 embodiment is shown in FIG. 2) and a channel switch IC 21 (for example, Texas Instruments' SN76750) and peripheral elements such as diodes and resistors. In the (down) ring counter, the output terminal 23 is switched by the pulse of the input 22.For example, when the outputs are from channel (hereinafter referred to as CH) 1 to CH12 as shown in the figure, assuming that CH1 is active at first, the input When one pulse enters, it moves to CH2
becomes active. Similarly, from CH2 to CH
3. Switching from CH3 to CH4 and CH12
When it reaches that point, it returns to CH1 with the next pulse. Channel switching can also be done using push buttons on the front panel of the TV. (Not shown) The output 24 of this tuning circuit is used as a TV (chain voltage) for the tuner 2.
(FIG. 1), and the channel is selected by changing the capacitance of the varicap. UHF,
It is clear that VHF sharing is possible. For example, if the IC shown in Figure 2 is dedicated to VHF, it would be better to provide an IC dedicated to UHF. Chuna 2 in Figure 1 is
The decoder and control signal generation circuit 13 receives input signals from the operation keys and the display unit 18, although it involves band switching operations for VHF low band, high band, and UHF. A well-known matching function that refers to the match between the program number read from the buffer memory 5 and the program code read from the buffer memory 5 is included.

Here, for example, the decoder and control signal generation circuit 13 has a fixed memory for storing a program number input from an operation key and a character program designation key provided on the display unit 18, such as a numeric keypad, and a buffer memory 5 to read out the program number. It includes a receiving memory that stores the currently received text program that stores the program code, and it is checked whether the contents of the fixed memory (program number) match the contents of the receiving memory (program code). This includes a configuration that can display the text program specified by the text program designation key.

In this embodiment, in addition to this well-known reference function, the decoder and control signal generation circuit 13 is designed as follows to enable automatic channel selection.

That is, when the selection mode key is operated on the operation key and display section 18, the program code is read out without being based on the reference function that detects a match between the program number and the program code read out from the buffer memory 5. A function is provided to control the input of the contents into the pattern memory 15 or color memory 16. It can be understood that this can be achieved by using the signal of the program code read out from the buffer memory 5 in the same way as the match signal when the program number and the program code from the buffer memory 5 match. That is, a gate or the like may be opened so that the program code can be outputted by the comparison section that detects a match regardless of whether or not the program number is input.

Therefore, in this selection mode, all the text information of the received text programs is input from the buffer memory to the pattern memory 15, and all the text programs are displayed continuously. In this selection mode, the teletext detection circuit 7 and the character number comparison circuit 8 are operated by the control signal as described above.

The operation key and display unit 18 is provided with a stop key, and when this stop key is operated, the decoder and control signal generation circuit 13
are the teletext detection circuit 7 and the teletext program comparison circuit 8
It is controlled to stop the operation of the program, and to fix the state in which only the text program currently being received is displayed.

For example, the program code stored in the reception memory (the program code of the text program currently being received) is stored in the fixed memory, and the system returns to the normal text reception state in which the reference function is activated. That is, instead of the program number specified by the text program designation key, the fixed memory stores the program code (corresponding to the program number) of the text program currently being received when the stop key is operated.

When selecting a text program, while the receiver is receiving the text program, first operate the operation keys, particularly the selection mode key, to enter the selection mode.

In this mode, the character program comparison circuit 8 operates, stores the first program code read out from the buffer memory 5, and compares this with program codes read out thereafter. The character information that comes is stored in the pattern memory 15 and color memory 16, and is read out continuously and displayed on, for example, a cathode ray tube.

Eventually, when the receiving station's text program completes its cycle, the text program comparison circuit 8 outputs a pulse because the stored program code and the program code read from the buffer memory 5 match, and the channel selection circuit 6 is activated. The receiving station changes. If the teletext program is not being broadcast at this receiving station, the teletext detection circuit 7 outputs an output, and the channel selection circuit 6 operates to further switch the receiving station.

The program code of the first text program received at this receiving station is input to the text program comparison circuit 8 and stored in the same manner as above.

In the same manner as described above, once the text program has completed one cycle at the receiving station, the channel selection circuit 6 operates and switches to the next receiving station.

When a desired program is found during the operation, another operation key, particularly a stop key, is operated to stop the reception of the desired text program and continuously display only this program. That is, the mode changes to one in which only the text program currently being received is received.

When returning to the original selection mode using a new operation key, especially the selection mode key, the operation returns to the above, but at this time, the text program comparison circuit 8 stores the program code to be sent next, and this is the standard program code. Programs that are input later are compared with this. When the programs complete one cycle and the first program corresponding to the standard program code arrives, the channel is switched to the next channel.

The same operation as described above is performed on the next channel, and the channels are switched one after another, and after the last channel, the channel returns to the first channel and the same operation is performed again.

According to the teletext receiver of the present invention, when selecting a teletext program, the reception channel can be automatically switched without having to switch each time. It changes after being displayed. For example, when you want to see shopping information, after watching a shopping information program on a certain channel, you can automatically switch to the next channel and watch the shopping information program on that channel. It would be convenient if you could use the 1 o'clock stop and then watch the next channel. In this way, when selecting a text program, you can save the trouble of switching channels, and in other words, you can watch your desired program from the channels that are displayed continuously, with all channels as one teletext broadcast without being conscious of the channel. I can do it.

[Brief explanation of the drawing]

FIG. 1 shows a block diagram of an embodiment of the teletext receiver of the present invention, and FIG. 2 shows a partial block diagram of the same. 2: Chuyuna, 4: Character signal extraction gate, 5:
buffer memory, 6: channel selection circuit, 7: teletext detection circuit, 8: teletext program comparison circuit, 13: decoder and control signal generation circuit, 15: pattern memory,
16: Color memory, 18: Operation keys and display section.

Claims (1)

[Claims] 1. In a teletext receiver that has a receiving function that receives information multiplexed and transmitted in a time division manner during the vertical blanking period of a television signal, stores it in memory, and continuously reads and displays it. , in the teletext program selection mode, the program code of the teletext program that arrives first is stored and compared with the program code that arrives after that, and a circuit that outputs a signal when the same program code arrives and detects the presence or absence of teletext. and a channel selection circuit that switches the reception channel of the television in response to the outputs of both circuits, and has a control means that fixes the unchanging operating state of the teletext program in response to an operation. A teletext receiver characterized by: