KR0143973B1 - Circuit for correcting character deviation of tv monitor - Google Patents

Abstract

The present invention relates to a character deviation correction bar-up and a circuit on a TV monitor, and in particular, it is suitable to correct a position deviation of a character in an internal mode and an external mode when a character is mounted on a TV monitor using an on-screen display integrated circuit. will be.

In the conventional technology, a character signal can be loaded on a TV screen by generating a relatively accurate synchronization path using two oscillator circuits in an internal mode, but an input video signal in an external mode is an ideal type of synchronization pulse (T = 5.0). [us]) is deformed to show the deviation of the character position in the internal mode and the external mode due to the delay of the horizontal and vertical synchronization signals.

Therefore, the present invention constitutes a character deviation correction method and circuit for the purpose of correcting a positional deviation of a character generated as the horizontal synchronous signal and the vertical synchronous signal, which are used when loading a character on a screen, are distorted.

Description

Character deviation correction circuit on TV monitor

1 is a block diagram of a conventional OSD circuit

2A is a waveform diagram of a horizontal synchronous and vertical synchronous signal used in a TV.

(b) is the character position explanatory drawing in internal mode / external mode on the monitor

Figure 3 (a) is an ideal horizontal synchronization signal waveform

(b) shows a distorted horizontal synchronization signal waveform

4 is a character deviation correction circuit diagram of the OSD circuit according to the present invention

5 is a flowchart illustrating the character deviation correction operation in the MCU unit according to the present invention.

* Explanation of symbols for main parts of the drawings

10. ODS (On Screen Display) Integrated Circuit 20. MCU (Micro Control Unit)

30. Synchronous Oscillator Circuit for NTSC / PAL 40. Synchronous Oscillator for Character

50. Synchronous separator 60. Synchronous detector

70. Clamp circuit 80. Video input buffer

90. Synchronization input buffer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and circuit for character deviation correction on a TV monitor, and more particularly, when the character is mounted on a TV monitor using an on-screen integrated circuit. This is to correct the positional deviation of the character.

The conventional OSD circuit is composed of a crystal (X-Tal) and a capacitor (C ₁ ) (C ₂ ) as shown in Figure ₁ the vertical synchronization signal of the NTSC (National Television System Committee) / PAL (Phase Alternation by Line) V-Sync) and a horizontal oscillation signal (H-Sync) for NTSC / PAL to generate a synchronous oscillation circuit 30, a coil (L ₁ ) and a condenser (C ₃ ) (C ₄ ) for the NTSC / PAL Character oscillation circuit section 40 for determining character position in accordance with the vertical / horizontal synchronous signal generated in the synchronous oscillation circuit section 30, synchronous separation section 50 for separating the vertical / horizontal synchronous signal, separated horizontal A horizontal synchronous detection unit 60 for detecting a synchronous signal, a micro control unit (hereinafter referred to as MCU) unit 20 for controlling internal / external mode operation by the horizontal synchronous detection signal, and a video signal OSD integrated circuit unit 10 for displaying a character on the TV monitor according to the input It is configured.

In the OSD circuit of this configuration, there are generally two modes of displaying characters on a TV monitor using an OSD integrated circuit, one of which is an internal mode and the other of which is an external mode. Character is loaded on the TV monitor by using the oscillation signals of the NTSC / PAL synchronous oscillation circuit unit 30 and the character oscillation circuit unit 40 in the state that is not input, and the NTSC / PAL signal is input in the external mode. Since the NTSC / PAL synchronization generating unit is not used, the character is loaded on the TV screen using only the oscillation circuit for the character, and the synchronization separating unit 50 used in the two modes is as shown in FIG. It is used to load the characters by separating the horizontal sync (H-Sync) and the vertical sync (V-Sync). When the horizontal sync is input to the sync detector 60, the window comparator is used to , And outputs the row is determined by the internal mode / external mode, the control operation of the MCU unit 20.

However, the above-described prior art configuration can generate a synchronization signal of a relatively accurate shape using two oscillator circuits in the internal mode so that the character can be loaded on the TV screen, but the video signal input in the external mode is shown in FIG. In the internal mode and the external mode, as shown in FIG. 2 (b), the synchronization pulse (T = 5.0 [us]) of the ideal type is transformed as shown in (b). There is a deviation in the character position of.

Accordingly, an aspect of the present invention is to provide a character deviation correction method and circuit for the purpose of correcting a positional deviation of a character generated as a horizontal synchronous signal and a vertical synchronous signal, which are used when loading a character on a screen, are distorted.

In order to achieve the above object, the character deviation correction method of the present invention comprises a first step of setting an initial value for a position in an internal mode, and an initial value and a count register for a reference value of an internal mode and an external mode, and entering through a synchronization input port. The second step is to increase the count register by counting the horizontal sync signal and counting while it is the logic 1 of the sync pulse, and compare the count register value with the reference value to adjust the position of the character so that the difference value is close to the reference value of the internal mode. In order to achieve the above object, the character deviation correction circuit of the present invention adjusts a clan circuit for stabilizing a synchronization signal of an input video signal and a DC level of the input video signal. The video input buffer to be used and the characters used in the internal and external modes Controls the oscillation circuit section, the synchronous oscillation circuit section for NTSC / PAL used for generating the synchronous signal in the form of the TV signal in the internal mode, the synchronous separation section for detecting the synchronous signal in the external mode, and the MCU in the internal / external mode. Synchronous detection unit, which is an external video detection circuit, and a synchronous input buffer unit which sets an input port to the MCU so that the horizontal synchronization signal can be counted for 1 logic at the MCU, and horizontal synchronization through the input port configured as the ceramic input buffer unit. It is defined as an MCU unit for counting a signal and controlling an internal mode / external mode operation according to the detection signal of the pottery detector so that the OSD unit can operate normally. This will be described in detail with reference to the accompanying drawings.

4 is a block diagram of the character deviation correction circuit of the OSD circuit according to the present invention, as shown in the figure, the clamp circuit unit 70 for stabilizing the synchronization of the video signal input to the OSD integrated circuit unit 10, and the input, A clamp circuit 70 for stabilizing the synchronization of the video signal to be input, a video input buffer 80 for adjusting the DC level of the input video signal, and a character oscillator circuit 40 used in the internal mode and the external mode. ), A synchronous oscillator circuit 30 for NTSC / PAL used for generating a synchronous signal in the form of a TV signal in the internal mode, a synchronous separator 50 for detecting a synchronous signal in the external mode, and an internal mode / external In the mode, the synchronization detection unit 60, which is an external video detection circuit that can control the MCU unit 20, and the synchronization input buffer unit, which sets an input port to count the horizontal synchronization signal for one logic in the MCU unit. 90, the horizontal synchronization signal is counted through the input port set as the synchronization input buffer unit, and the OSD unit 10 operates normally by controlling the internal mode / external mode operation according to the detection signal of the synchronization detection unit 60. It consists of the MCU unit 20 to enable.

5 is a flowchart of the character deviation correction operation in the MCU unit according to the present invention. As shown in the figure, an initial value for the character position in the internal mode is set (step S1), and the external mode / internal mode is shown. After setting the initial value with respect to the reference value of time (step S2), the first step of setting a count register for counting the synchronization pulses (step S3), and checking whether the horizontal synchronous signal inputted through the synchronization input port is logic 1 (step S2) S4), the second step of increasing the count register set in the first step (step S5) to check whether the logic 0 is applied (step S6) and repeating until the logic 0, and the count register value And a third step of comparing the preset reference value (step S7) and correcting the position (step S8) so that the difference value approaches the reference value of the internal mode.

Operation and effects of the present invention configured as described above are as follows.

4 and 5, a video signal input to the video input buffer unit 80 includes a resistor R ₄ and two diodes D ₁ D ₂ to stabilize synchronization. The clamp circuit unit 70 removes the signal from which energy diffusion has been removed again to prevent synchronous shaking, and the clamped video signal is adjusted through the video input buffer unit 70 to satisfy the input of the OSD unit. Inputted to the OSD integrated circuit unit 10, the clamped video signal is input to the synchronous separation unit 50 is separated into a horizontal synchronous signal and a vertical synchronous signal, respectively, and used to load the character in the OSD integrated circuit unit 10 At the same time, the internal mode and the external mode of the MCU unit 20 are controlled by using the horizontal synchronization signal.

This control operation detects the presence of horizontal synchronization by the synchronization detecting unit 60 and recognizes the presence of a video signal to the MCU unit 20 as high and low at the output terminal. The video enable (V-ENABLE), clock (CLOCK) and data (DATA) and the signal (OSD-BUSY) indicating that the current OSD integrated circuit unit (10) is loading the character on the screen so that the (10) can operate normally. ), And the character is put on the TV screen using this method.

In the internal mode, since the horizontal synchronous and vertical synchronous outputs of the ceramic separator 50 are not generated, the synchronous oscillation circuit 30 for NTSC / PAL is used, and the crystal (X-TAL) generally used is NTSC. 14,31818 MHz for the PAL method and 17,737475 MHz for the PAL method, the position of the character uses the oscillation circuit part 40 for the character, and the output of the synchronous detection part 60 drops to logic 0, and the MCU part 20 Control to operate in internal mode.

Position correction of the character between the two modes of the operation as described above by setting the horizontal synchronous signal from the output of the synchronous separation unit 50 as the input of the MCU unit 20 through the synchronous input buffer unit 80, the synchronous pulse It is possible to correct the position by the time count routine in the MCU unit 20 by using the first, the MCU unit 20 initializes the position of the character in the internal mode by using the horizontal synchronization, vertical synchronization (step S1). Select the reference value so that it can count faster than the horizontal synchronization signal in the external mode and the internal mode (step S2), and set the register to count the logic 1 value of the synchronization signal by setting the count register (step S3). do.

After that, the input port of the MCU unit 20 is set by using the synchronous pulses received through the synchronous input buffer unit 90, and the time of the logic 1 of the synchronous pulses is counted using a time count routine. Is increased (steps S4, S5).

At this time, when the input port of the MCU unit 20 drops to logic 0, the count is stopped (step S6), the count register is compared with the reference value (step S7), and the position of the character is corrected so that the difference of the comparison is closer to the reference value of the internal mode. (Step S8), the character is loaded on the TV screen.

Therefore, the present invention is useful to be able to solve the visual dissatisfaction on the screen because it is possible to correct the positional deviation of the character in the internal mode / external mode by adding a simple circuit and time count program.

Claims (2)

A method for correcting the position of a character on a screen by using an OSD integrated circuit by the MCU's internal / external mode control operation, wherein the initial value of the character position in the internal mode and the reference value in the external / internal mode A first step of describing a count register for counting an initial value and a synchronous pulse; a second step of counting a logic register of horizontal synchronous pulses coming through the synchronous input port into a count register; and a count register of the second step And a third step of comparing a value with a reference value of the first step and correcting the position of the character so that the difference value is close to the reference value of the internal mode. OSD circuit which enables characters to be loaded on the screen using the OSD integrated circuit unit 10 by the internal / external mode control operation of the MCU unit 20 determined by the output of the synchronization detection unit 60 which is an external video detection circuit. A clamp circuit 70 for stabilizing synchronization of a video signal input to the OSD integrated circuit unit 10, a video input buffer unit 80 for adjusting a DC level of an input video signal, and a video; By setting the horizontal synchronizing pulse output of the synchronizing separator 50 separating the synchronizing of signals into the input port of the MCU unit 20, the synchronizing pulse can be counted so that the MCU unit 20 can count the logic 1 of the synchronizing pulse. The applying seek is a character deviation correction circuit on a TV monitor, characterized in that it comprises a synchronization input buffer unit (90).