JPS6349235B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention deletes one line while moving the displayed characters when the characters displayed on the cathode ray tube of a television receiver overflow, and when displaying a new line, the line movement is gradual. This invention relates to a method for moving characters on a television receiver screen.

Conventionally, when characters are printed one after another on a cathode ray tube using a word processor, etc., and the characters on the screen overflow, the first line disappears from the screen and the next line is printed and displayed. When the characters on the screen move one line at a time, all the lines move instantly, which can sometimes cause viewers to become confused and lose sight of what they are looking for.

The present invention has been made in view of the above points, and its purpose is to combine a digital circuit with an analog time constant circuit, and to control line movement by this time constant circuit. To provide a method for moving characters on a television screen in which line movement is performed slowly and the circuit is simple and can be manufactured at low cost.

Next, one embodiment of the present invention will be described with reference to the drawings.

Figure 1 shows a device for recording character signals on a magnetic tape, 1 is a television camera, 2 is a monitor television, and 3 is a device that converts the brightness of the character signal from the television camera 1 into "1" and "0". A/D converter, 4
serializes the pixel signals from the A/D converter 3 →
A serial/parallel shift register for parallel conversion; 5 is a video synchronizing signal generator; 6 is a clock generator; 7 is a write address counter; A latch pulse is sent to the serial/parallel shift register 4 for every 8 pixels, and the address switch 9
Send the light address to. 8 is address switch 9
RAM 9 stores the 8 pixels from the serial/parallel shift register 4 using the output from the write address counter 7, stores the 8 pixels in the RAM 8 using the output from the write address counter 7, and stores the 8 pixels from the read address counter 13 using the output from the read address counter 13. RAM switch that reads each
10 is a parallel-to-serial shift register that converts the pixel signals from RAM 8 from parallel to serial; 11 is a modulator that modulates pixel "0" into one wave of 3000 Hz, for example, and modulates pixel "1" into two waves of 6000 Hz, for example. . 1 is a recorder including a recording head; 13 is a read address counter that switches the address switch 9 with a clock from a recording clock generator 16; and 14 is a system controller that controls RAM 8 by operating the operation panel 15. For clearing, for line break, 3
A blank (non-recorded area) for two pixels is created, and recording start, stop, etc. are controlled. 16
is a recording clock oscillator that generates a 3000Hz clock.

Next, to explain the operation based on the above configuration,
First, the television camera 1 is operated synchronously at 5 MHz generated by the video synchronization signal generator 5, and a poetry card on which eight lines of poetry are written is positioned and photographed while viewing on the monitor television 2.

In this case, during one horizontal scan, the clock generator 6
Create a clock equivalent to 256 pieces (32 x 8 lines),
A/D converter 3 to set the brightness and darkness of characters to “1” and “0”
Convert one row and one horizontal column into 32 pixels and 192 columns from top to bottom, totaling 6144 pixels in the correct order.
The decomposed pixels are sent to the serial/parallel shift register 4, where they are stored every 8 pixels, converted from serial to parallel, and sent out once to be sent to the RAM 8.

On the other hand, the write address counter 7 sends a latch pulse to the shift register every 8 pixels based on the signal from the video synchronizing signal generator 5 and the clock, and also sends the write address to the address switch 9.

Note that the pixel signals decomposed by the 5 MHz clock have a high frequency and cannot be recorded on magnetic tape as they are, so they are converted to character signals of the audio band frequency. The frequency of the character signal is determined by the speed at which characters are formed during playback, so for example, if one line is to be formed on the screen of a television receiver in 2 to 3 seconds, the required frequency will be 6144 ÷ 3 = 2048 Hz to 6144 ÷ 3. The range is 2 seconds = 3072Hz. This is the stable playback frequency of normal magnetic tape, around 3000Hz, so you can expect clear images.

This 3000Hz clock is generated by the recording clock oscillator 16, the system controller 14 is controlled by the operation panel 15, the address switch 9 is controlled by the recording start/stop operation of the recorder 12, and the read address counter 13 records the data. The read address and write address created by the clock are switched, the pixel signal is read from the RAM 8, and the parallel to serial shift register 10 converts it from parallel to serial.
It is taken out at the timing of the clock from the recording clock generator 16, and the pixel "0" is set by the modulator 11.
Pixel "1" modulates one wave of 3000 Hz and two waves of 6000 Hz and sends them to the recorder 12. Therefore, character signals are recorded on the magnetic tape.

By the way, with the above-mentioned operation alone, pixel signals are simply sent out continuously, and in order to reproduce characters, their delimiters, line feed commands, and character clear commands must also be recorded.

Therefore, if this type of instruction, which has been commonly used in the past, was recorded using digital bits, the instruction decoding circuit would be complicated and expensive. Depending on the length of time, a method was adopted to decipher various instructions. In other words, 2 wave blanks are divided into 32 pixels, 0.5 second blanks are used as line feed commands, and 1
A blank of more than one second is inserted into the recording signal as a RAM 8 clear command. Specifically, a 32-pixel blank is generated by the system controller 14 and is created by stopping two blank waves. Further, blanks for line feed commands and clear commands are created by pressing a dedicated operation button provided on the operation panel 15 and mutating the signal from the modulator 11 for a time corresponding to each time. According to this method, even if there is a dropout in the recorded signal, no practical problem occurs except that the screen is distorted or lines are changed, and the circuit is simple and the device can be made simple.

The above operation is repeated for each line of the screen to be photographed and recorded, and a character signal is recorded on the second channel of the magnetic tape in time with the karaoke on the first channel.

The above is a description of the method of recording signals on a magnetic tape. Below, a method of reproducing a magnetic tape recorded in this manner will be described with reference to FIG. 2.

17 is a magnetic head, 18 is an amplifier, 19 is a character signal detection circuit, 20 is a serial/parallel shift register that converts the signal from the detection circuit 19 from serial to parallel;
1 is a clock regeneration circuit that detects the clock signal in the signal from the amplifier 18; 22 is the regeneration circuit 21;
23 is a line counter for dividing each line by the output from the line feed blank detection circuit 26, and 24, 25, and 26 are amplifiers 18.
RAM clear blank included in the signal from
A detection circuit detects a two-wave blank and a line feed blank, respectively; 27 is an address switcher that switches the write address and read address every 8 pixels to switch the address of the RAM 33; 28 counts the row output signal from the row counter 23; 7th line detection counter that sends an output when counting the line, 29 is 7
Line detection counter 28 and line feed blank detection circuit 2
When the output from 6 is outputted through an AND circuit 40, a scroll counter sends out an address signal for moving the screen line by line, 30 is an oscillator that oscillates 5MHz for video synchronization, and 31 is an address counter. , 32 is a scroll counter 29
address signal and address counter 31 made by
an adder for adding address signals made by 33;
is a RAM, 34 is a parallel-to-serial shift register for converting character signals read out from the RAM 33 from parallel to serial, 35 is a high frequency modulation circuit, and 36 is a receiver. 37 is a V sync, and 38 is an H sync, and a synchronization signal generated by the V sync and H sync 38 is applied to the high frequency modulation circuit 35 via an OR circuit 41.

Reference numeral 39 is a scroll controller having a circuit as detailed in FIG. This is to make it happen slowly. That is, the line feed signal is sent to H via the scroll controller 39.
In addition to the sync 38, this is done by gradually changing the gap between the horizontal synchronizing signals.

FIG. 3 will be explained below. Q ₁ to _{Q 4} are transistors, R ₁ , R ₂ , C ₁ are resistors and capacitors that make up the time constant circuit, D ₁ is a light emitting diode, and Z is a
A light receiving element such as CdS, R ₃ and C ₂ are resistors and capacitors forming a time constant circuit, and M ₁ and M ₂ are one-shot multi.

Next, to explain the operation, when the screen reaches a predetermined number of lines (7 lines in this embodiment), a low level output is sent from the 7th line detection counter 28, so the transistor Q ₁ is off and waits for scrolling. Then, when the line feed blank detection circuit 26 sends out a low level output that is a line feed signal, the transistor
Q ₂ is turned off, and therefore the current flowing to the light emitting diode D gradually increases due to the time constant of the time constant circuit made up of resistors R ₁ , R ₂ and capacitor C ₁ . Therefore, the time constant of the time constant circuit consisting of the light-receiving element Z, resistor R ₃ and capacitor C ₂ becomes smaller, and the position of the horizontal synchronization signal is relatively shifted before the video signal, causing the screen to slowly appear. Move to the right.

After that, when the line feed signal rises, transistor _Q2 turns on, and the charge in capacitor _C1 is instantly discharged to prepare for the next scroll.

Next, the operation of the circuit shown in FIG. 2 will be explained.

When a magnetic tape recorded by the above-mentioned recording apparatus shown in FIG. The amplified character signal is then divided into a character signal, a clock signal, and a blank signal. Character signals of 3000 Hz and 6000 Hz detected by the character signal detection circuit 19 are converted from serial to parallel by a serial/parallel shift register 20 and recorded in the RAM 33. The clock reproducing circuit 21 extracts only the clock, operates the 32-pixel counter 22 and the row counter 23, and sends out a write address signal for the RAM 33 from each. Then, the signal detected by the two-wave blank detection circuit controls the 32-pixel counter 22 to
Separate every two pixels. When the line feed blank detection circuit 26 detects a blank of about 0.5 seconds, the line counter 23 is controlled to separate each line. When the RAM clear blank detection circuit 24 detects a blank for one second or more, the RAM 33 is cleared and the entire screen of the receiver 36 is erased.

On the other hand, when the seventh line detection counter 28 detects the seventh line, a signal from the line feed blank detection circuit 26 is sent to the scroll counter 29, which sends an address signal for moving the screen one line at a time. In addition, the oscillator 30 oscillates a 5MHz signal for video synchronization and sends it to the address counter 31.The adder 32 adds the address signal generated there and the address signal generated by the scroll counter 29, and switches the address as a read address. It is sent to the container 27. So set the write address and read address to 8.
The address of the switching RAM 33 is controlled for each pixel. The character signal read from the RAM 33 is converted from parallel to serial by a parallel-serial shift register 34 and sent to a high frequency modulation circuit 35. In this high frequency modulation circuit 35, a synchronizing signal generated by the V sync 37 and H sync 38 circuits is added to perform modulation to display the image of the character signal on the receiver 36.

On the other hand, with the conventional scrolling method, lines change instantly when scrolling, making it confusing to know which line you were reading up until now. Therefore, in order to scroll slowly, a scroll controller 39 as shown in FIG. 3 described above is connected.
The line feed signal is passed through the scroll controller 39 to gradually change the gap between the horizontal synchronizing signals, thereby allowing the line to move slowly. After the row movement, the synchronization signal returns to its original state at the same time as the display address is shifted.

Although the above-mentioned embodiments have been described with respect to magnetic tapes, it goes without saying that this can also be applied to audio disks.

Further, in this embodiment, a character display for karaoke has been described, but it can be used as long as the characters are displayed sequentially like a word processor and moved line by line when the screen overflows.

As described above, in a character display method in which characters are sequentially displayed using digitally processed pixel signals, when characters on the screen overflow, a line feed command signal is sent to a time constant circuit made of an analog circuit. Since the synchronization signal is delayed by gradually changing the voltage, line movement occurs slowly, so the person looking at the characters does not feel confused, and the circuit is simple. This has advantages such as being able to be manufactured at low cost.

[Brief explanation of the drawing]

The figures show an embodiment of the apparatus used in the method of the present invention, in which Fig. 1 is a block diagram of a recording device, Fig. 2 is a block diagram of a reproducing device, and Fig. 3 is a scroll control circuit which is a part of the same. It is a diagram.

Claims (1)

[Claims] 1 When characters are displayed in sequence using digitally processed pixel signals, and when one line of characters is displayed, characters are displayed on the next line using a line feed command signal, and the above occurs when the characters on the screen overflow. A method for moving characters on a television receiver screen, characterized in that the voltage of a line feed command signal is gradually changed, thereby delaying a synchronizing signal, and causing line movement to occur slowly.