JPH067371U - Character position correction circuit on the screen - Google Patents

Abstract

(57) [Abstract] [Purpose] In a television receiver that can set the display position of character information on the screen numerically, the start position of writing a character block is automatically corrected to start writing in a normal state. Correct to position. [Structure] A detection circuit (5) that compares the display position signal of the character block (17) with the horizontal synchronizing signal and outputs a detection signal V ₂ corresponding to the actual display position, and the numerical setting of the character block (17) By the reference value circuit (7) which outputs the reference signal V ₁ corresponding to the position, the comparison circuit (6) which compares the magnitude of the detection signal V ₂ and the reference signal V ₁ , and the output of the comparison circuit (6), A microcomputer (2) that controls the change of the character block display position,
A character position changing circuit (2 that moves the horizontal writing position of the character block on the screen according to the output of the microcomputer (2)
5) It is configured by and so that the writing start position of the character block automatically appears at the predetermined position where the numerical value is set on the screen.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a correction circuit for correcting the display position of character information on a screen in an image device such as a television receiver capable of displaying character information on the screen of a cathode ray tube.

[0002]

[Prior art]

 In a conventional television receiver, various information such as channel number, volume, and time is displayed by an operation (on-screen) that displays character information in addition to video. These pieces of information are stored in the memory inside the television receiver, which is read out and displayed on the screen. The character information is determined by numerically setting the writing position of a character block area capable of displaying a maximum of 24 characters in the vertical and horizontal directions. The character block is an area in which character information can be displayed, and its vertical position can be set to any position of 128 steps which is set numerically by counting the horizontal synchronizing signal of the television receiver. Further, the writing position of the character block can be set to an arbitrary position of 64 steps in the horizontal direction by counting the clock signal of 4 MHz generated from the display clock oscillation circuit.

The setting of the character position is performed at the time of factory shipment of the television receiver. However, since the quality of electronic parts such as capacitors forming the display clock oscillation circuit varies, the character block The write-out position does not always appear at the specified position set numerically.

For example, in FIG. 2, when the writing position of the character block (17) on the screen (16) is set to a value of H _{1 in} the horizontal direction from the end as shown in FIG. However, the writing position of the character block (17) may be delayed in the horizontal direction as shown in FIG. 10 (a) and may be advanced from H ₂ (H ₂ > H ₁ ) or a predetermined position (H ₂ <H ₁ ). In order to make the writing position of the character block (17) appear at the specified position (Fig. 2b) that is set numerically, it is necessary to manufacture the display clock oscillator circuit with accurate and expensive parts. There is a problem that the manufacturing cost becomes high.

An object of the present invention is to make a display clock oscillation circuit by a component having a variation in provisional performance, so that even if there is an error in the frequency of the display clock, the display position of the character block is automatically moved. Then, the text information is displayed at the predetermined position where the numerical value is set.

[0006]

[Means for Solving the Problems]

The present invention compares the display position signal of the character block (17) with the horizontal synchronizing signal and outputs the detection signal V ₂ corresponding to the actual display position, and the detection circuit (5) and the character block (17). The reference value circuit (7) that outputs the reference signal V ₁ corresponding to the numerical setting position, the comparison circuit (6) that compares the magnitude of the detection signal V ₂ and the reference signal V ₁ , and the comparison circuit (6) The microcomputer (2) that controls the change of the character block display position by the output, and the character position change circuit that moves the horizontal writing position of the character block on the screen according to the output of the microcomputer (2) (25 ) And a correction circuit configured by.

[0007]

[Action]

The detection circuit (5) outputs a detection signal V ₂ corresponding to the actual display position according to the writing position of the character block relating to the on-screen. On the other hand, since the reference value circuit (7) outputs the reference signal V ₁ corresponding to the numerical setting position, by comparing V ₂ with V ₁ , the character block actually appearing on the screen is at the predetermined position or is advanced. You can detect whether you are out or behind.

When the display position is delayed (FIG. 2A), the microcomputer reduces the set value of the built-in horizontal register and moves the actual display position in the forward direction.

On the contrary, when the actual display position is ahead of the predetermined position, the microcomputer increases the value of the horizontal register and delays the display position of the character block.

By the above-mentioned correction processing according to the program of the microcomputer, the detection signal V ₂ of the actual display position can be matched with the reference signal V _1, and the writing position of the character block can be displayed at the predetermined position where the numerical value is set. .

[0011]

【Example】

 The TV signal received by the antenna and tuned by the tuner (11) in FIG. 1 becomes a video signal through the intermediate image frequency circuit (12) and the video output circuit (13), and the brown tube (16). The image is displayed on. The video output circuit (13) further supplies a vertical synchronizing signal (V) and a horizontal synchronizing signal (H) to the synchronizing signal counter (22) and the character generator (24). The sync signal counter (22) counts the horizontal sync signal (H) immediately after the vertical sync signal (V) is issued and outputs the count value to the microcomputer (2). The microcomputer (2) controls the video blanking circuit (14) to be turned on and off based on the output of the sync signal counter (22), and the specified range of the horizontal period is displayed as a character information image corresponding to the character block for which a numerical value has been set. While the background screen is blanked only in part, the character image is added to the background screen, and this blanking process makes the character information displayed on-screen easier to read. The character image is stored in the memory (4).

The display clock oscillating circuit (3) generates a pulse at regular intervals, the counter (31) counts the number of pulses after the horizontal synchronizing signal is issued, and the next horizontal synchronizing signal is issued. It was previously reset and is repeating this.

The writing position of the character block is set by setting a numerical value in the reference value circuit (7). The microcomputer (2) reads the character block from the memory (4) and outputs the character to be on-screen to the character generator (5) when the count value of the counter (31) reaches the set value representing the writing position. . The character generator (24) outputs the RGB pulse indicating the character to the set position based on the vertical synchronizing signal (V) and the horizontal synchronizing signal (H), and the signal addition and synthesis circuit (15) outputs the television image signal. Is added and displayed on the screen of the cathode ray tube (16).

Although the above-mentioned configuration is a known character display device in a television receiver, the present invention reads the character block signal (17) for confirming the display position from the memory (4) and outputs it to the computer (2). Output to the character generator (24) and to the detection circuit (5) connected to the microcomputer (2).

The detection circuit (5) has an exclusive OR circuit (51) and an integration and sample hold circuit (52). The exclusive OR circuit (51) receives the horizontal sync signal (H) from the video output circuit (13) and the character block signal (17) from the microcomputer (2) at the same time. The output obtained by the logical sum processing is supplied to the integration and sample hold circuit (52).

FIG. 3 shows signals of respective parts of the detection circuit (5). One cycle (1H) of the horizontal synchronizing signal (H) represents the width of the screen of the cathode ray tube (16). When the display clock oscillator circuit (3) is in a normal oscillation state, the write start position when the counter (31) counts the set number of clocks is the position at which time T _{1 has} elapsed since the horizontal synchronization signal was issued. (Figure b).

FIG. 3C is a display state of the character block when the oscillation cycle of the display clock oscillation circuit (3) is delayed from the normal state. When the counter (31) counts the set number of clocks and the writing start position of the character block (17) is determined, the time T ₂ has already passed from the horizontal synchronizing signal (H), and the character block range within the screen The specified number of characters cannot be displayed in.

The exclusive OR of the determination signal of the character block (17) and the horizontal synchronizing signal (H) is as shown in the diagrams d and e, respectively. Figure d is a normal state, and Figure e is a shifted state corresponding to Figure c. When these signals are integrated and sampled and held, the voltage V 1 is output in the normal case, but the voltage V ₂ (V ₂ > V ₁ ) is output in the deviated state as shown in FIG.

The output is A / D converted (53), and the comparison circuit (6) compares the converter (61) with the reference value signal V ₁ of the reference value circuit (7) for a magnitude relationship. By this comparison, it is determined whether the writing position of the character block (17) on the screen is ahead of or behind the normal state, and it is corrected according to the program of Fig. 4 and displayed on the screen. The actual writing start position of the character block in the character block moves to the normal position.

The program of FIG. 4 is executed by an electronic circuit built in the microcomputer (2). When the comparison circuit (6) determines V ₂ > V ₁ , the terminal A of the microcomputer (2) is set to “H”. ” When the comparison circuit (6) determines that V ₂ <V ₁ or V ₂ = V ₁ , the terminal A of the microcomputer (2) is set to "L" (82).

When the terminal A of the microcomputer (2) is H, the set value of the character block display position stored in the horizontal register incorporated in the microcomputer is reduced by one step (83), and whether V ₂ matches V ₁ (84). If V ₂ > V ₁ in this determination, the process is repeated until V 2 = V ₁ .

When the writing position of the character block is behind the normal state, portA is “L”, so the set value stored in the horizontal register incorporated in the microcomputer is increased by one step, and V ₂ = V ₁ is obtained. The above process is repeated until.

When V ₂ = V ₁ , the microcomputer outputs to the character position changing circuit (25) and moves the writing position of the character block to the normal position (FIG. 3b). (86), output to the character generator (24), and display on the cathode ray tube screen via the addition circuit (15) (87).

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the scope of the utility model registration request or reducing the scope. Further, the configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the scope of claims for utility model registration.

[0025]

[Effect of device]

 According to the present invention, even if the cycle of the display clock oscillator circuit (3) is slightly different from the predetermined value, it can be corrected to a correct and normal state by software processing in the detection circuit (5), the comparison circuit (6) and the microcomputer. Therefore, the adjustment operation that was performed one by one at the time of factory shipment is no longer necessary.

Moreover, the parts of the display clock oscillator circuit (3) do not need high-precision and expensive parts, and inexpensive parts with some variations in performance can be used, thus lowering the manufacturing cost of the product. You can

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

2A and 2B are explanatory views showing the position of a character block on the screen and a corrected situation.

FIG. 3 is a waveform diagram showing a signal of a character block (17) in one horizontal section and a signal waveform of each part in a detection circuit (5).

FIG. 4 is a program for correcting a character block writing position in a microcomputer.

[Explanation of symbols]

 (16) CRT (17) Character block (2) Microcomputer (22) Synchronous signal counter (25) Character position change circuit (3) Display clock oscillator circuit (13) Counter (5) Detection circuit (6) Comparison circuit (7) ) Reference value circuit

Claims (1)

[Scope of utility model registration request] 1. A display device in which a writing position of a character block (17) on a screen is set in advance and a character is displayed at a predetermined position in the horizontal direction of a character block by counting a display clock. The detection circuit (5) that compares the display position signal of 17) with the horizontal synchronization signal and outputs the detection signal V ₂ corresponding to the actual display position, and the reference signal corresponding to the numerical setting position of the character block (17). Reference value circuit (7) that outputs V ₁ and a comparison circuit that compares the magnitude of the detection signal V ₂ and the reference signal V ₁
(6) and the output of the comparison circuit (6) controls the change of the character block display position, and the horizontal writing of the character block on the screen according to the output of the microcomputer (2). Character position change circuit (2
5) and a character position correction circuit on the screen, which is configured by and to correct the writing position of the character block (17) to a predetermined position set numerically.