KR19990018314A - Screen distortion correction device of TV receiver - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for correcting a screen distortion of a TV receiver. In particular, the present invention relates to an upper distortion phenomenon of an image signal generated by a voltage change of a phase detection circuit in a switching section of a head when a nonstandard signal (video signal) such as a VCR is input. The present invention relates to a screen distortion correction device for a TV receiver that delays an image signal by a synchronization signal so that the screen can be centered.

Conventionally, in the video head switching section, the voltage change of the phase detection circuit increases due to the disturbance of the vertical synchronizing signal in the head switching section due to the non-standard signal, and some correction time is required in the automatic frequency control circuit for correcting this. However, there is a problem that appears during the upper screen of the TV screen during this time.

The present invention is to delay the video signal by the delay means in accordance with the horizontal synchronization and vertical synchronization in order to prevent the upper screen distortion caused by the vertical synchronization signal in the switching section of the video head when the non-standard signal input to the VCR, etc., the delayed video signal vertical The deflection of the upper part of the screen can be corrected by allowing the screen to be positioned in the center of the center by delaying the delay means to compensate the deflection as much as the synchronization.

Description

Screen distortion correction device of TV receiver

According to the present invention, in the screen distortion correction of a TV receiver, a non-standard signal such as a VCR is input to prevent the TV screen from bending due to a voltage change of a phase detection circuit caused by a switching section of a video head. It relates to a screen distortion correction device.

The configuration of the screen distortion correction apparatus of the conventional TV receiver is shown in Figure 1,

A video signal processor 1 for demodulating and processing a composite video signal and outputting the color signal RGB, a synchronization separator 2 for receiving a composite video signal CVBS and separating vertical and horizontal sync signals; An automatic frequency control section 3 for controlling the frequency of the horizontal synchronization signal separated by the synchronization separation section 2, and a horizontal deflection section 4 for performing horizontal deflection by the horizontal deflection output signal of the automatic frequency control section 3; And a vertical deflection control unit 5 for generating a vertical triangular wave by synchronizing the divided input signal of the automatic frequency control unit with the vertical synchronization signal separated by the synchronization separation unit, and by the vertical deflection of the vertical deflection control unit 5. It consists of the vertical deflection part 6 which performs a vertical deflection.

On the other hand, the automatic frequency control unit 3 is a phase detector for detecting the phase difference by comparing the phase of the horizontal synchronization signal separated by the synchronization separator 2 and the flyback pulse fed back from the horizontal deflection output unit 34 ( 31) and the horizontal oscillator 32 for oscillating the horizontal oscillation frequency due to the phase difference detected by the phase detector 31 into a predetermined signal, and the oscillation frequency of the horizontal oscillator 32 is divided into a predetermined signal. And a horizontal deflection output unit 34 for outputting a horizontal frequency and a flyback pulse at an output divided by the division unit 33.

The horizontal deflection control unit 5 includes a vertical counter 51 for counting the input signal divided by the automatic frequency control unit 3 in synchronization with the vertical synchronization signal separated by the synchronization separation unit 2, and the vertical counter ( A vertical timing pulse generator 52 for generating a vertical timing pulse by a signal input from 51; and a vertical triangular wave oscillator for generating a vertical deflection triangle wave by the vertical timing pulse to drive the vertical deflection unit 6; 53).

As shown in FIG. 1, first, a composite video signal obtained by synthesizing a video signal and a sync signal when the video signal is a standard is separated from the video signal processor 1 and the synchronous separation. When input to the unit 2, the video signal processor 1 demodulates the composite video signal into an original signal and outputs it as a color signal RGB.

The sync separator 2 separates the horizontal sync signal and the vertical sync signal from the composite video signal, applies a horizontal sync signal to the automatic frequency controller 3, and applies a vertical sync signal to the vertical deflection control unit 5. Done.

The phase detector 31 of the automatic frequency control unit 3 detects an error voltage by comparing a phase with a flyback pulse fed back from the horizontal deflection output unit 34 to the horizontal synchronizing signal to oscillate the horizontal oscillator 32. The frequency is controlled to be constant.

The horizontal oscillator 32 oscillates the oscillation frequency by N times (N × f _H ) by the control signal of the phase detector 31 and divides the N by the division unit 33, and the division unit 33 The output signal divided at is applied to the vertical deflection output section 34 and the vertical counter 51 of the horizontal deflection output section 5.

In response to the divided signal, the horizontal deflection output unit 34 generates a horizontal frequency and a flyback pulse to perform horizontal deflection in the horizontal deflection unit 4.

Here, when pulsed noise is mixed in the composite video signal input to the automatic frequency controller 3, the pulsed noise is included in the separated sync signal, and thus, the synchronization is scattered and thus a stable screen cannot be obtained.

In order to prevent this, the automatic frequency controller 3 synchronizes the horizontal oscillation unit 32 one by one with respect to the input horizontal synchronization signal, so that the automatic frequency control unit 3 synchronizes the average period of several synchronization signals. It will have little effect on the screen, resulting in a stable screen.

On the other hand, the vertical counter 51 of the vertical deflection control unit 5 counts the division output of the frequency division unit 33 in synchronization with the vertical synchronization signal of the synchronization separation unit 2, and receives a counting result. At 52, a vertical timing pulse is generated.

By the generated pulses, the vertical triangular wave generator 53 generates a triangular wave for vertical deflection and applies it to the vertical deflection portion 6 to perform vertical deflection.

As described above, when the video signal is standard, there is no problem on the screen.

However, when a non-standard signal (video signal) is input due to the age of a video tape such as a VCR, disturbance occurs in the vertical synchronization signal separated by the synchronization separation unit 2 in the head switching section of the video. The voltage change of the phase detector 31 of the controller 3 is increased.

Due to the voltage change of the phase detector 31, the oscillation frequency of the horizontal oscillator 32 is also disturbed, and the start point of the horizontal scan is shifted at the beginning of the vertical scan by the oscillation frequency such that the upper part of the screen is bent. Warpage will occur.

In addition, the automatic frequency controller 3 needs a certain amount of time to correct the upper screen deflection as described above.

When the pulsed noise is mixed in the conventional composite video signal, the automatic frequency control unit synchronizes with the average period of a plurality of synchronization signals, thereby preventing the pulsed noise and obtaining a stable picture. However, when a video tape is worn out, a non-standard signal is inputted. Disturbance of the vertical synchronization signal in the head switching section causes the voltage change of the phase detector 31 to increase, resulting in an initial screen warp, and it takes some time to correct it, thereby providing a clear picture quality to the viewer. You won't be able to.

According to the present invention, when the non-standard signal is input from the VCR, the horizontal frequency scanning is performed using the storage means to prevent the warping of the upper part of the screen due to the start point of the horizontal scanning at the beginning of the vertical scanning. Delaying the starting point until it stabilizes, and shifting the deflection position by delaying the vertical timing pulse in order to prevent the image from being shifted to the lower side of the screen by the delayed signal, thereby improving the screen upper deflection in the non-standard signal input. .

1 is a block diagram of a screen distortion correction apparatus of a conventional TV receiver

Figure 2 is a block diagram of a screen distortion correction device of the present invention TV receiver

Figure 3 is a waveform diagram of each part of the screen distortion correction device of the present invention TV receiver

The configuration of the TV screen upper distortion correction apparatus of the present invention, as shown in Fig. 2, until the automatic frequency control unit 14 is stabilized at the horizontal scanning start point to correct the upper image distortion caused by the non-standard signal of the composite image signal Signal delay means 11 for delaying the signal, an image signal processor 12 for processing the video signal delayed by the signal delay means 11, and outputting the color signal; By the synchronization separator 13 for separating the horizontal synchronization signal, the automatic frequency controller 14 for controlling the frequency of the horizontal synchronization signal separated by the synchronization separator 13, and the automatic frequency controller 14 The horizontal deflection unit 15 which performs horizontal deflection with the input signal and the divided input signal of the automatic frequency control unit 14 are synchronized with the vertical synchronization signal separated by the synchronization separation unit 12. The vertical deflection control unit 16 controls the generated vertical timing pulse for a predetermined time and outputs the vertical triangular wave to the vertical deflection unit 17, and the vertical deflection is controlled by the vertical triangular wave controlled from the vertical deflection control unit 16. It consists of the vertical deflection part 17 which performs.

Meanwhile, the signal delay means 11 includes an A / D converter 111 for converting an analog composite video signal into a digital signal, an image storage means 112 for storing the digital video signal, and the stored video signal. D / A converter 113 for converting to an analog signal and timing generator 114 for generating timing signals WR and RR for controlling the image storage means 113 on the basis of the vertical synchronization signal. The automatic frequency controller 14 includes a phase detector 141 for comparing a phase of a horizontal synchronization signal and a flyback pulse, and a horizontal oscillator for oscillating an oscillation frequency with a phase difference detected by the phase detector 141. 142, a divider 143 for dividing using the oscillation frequency of the horizontal oscillator 142, and a horizontal deflection output unit for outputting a horizontal frequency and a flyback pulse at an output divided by the divider 143. 144.

The vertical deflection controller 16 includes a vertical counter 161 for counting the divided input signal of the automatic frequency controller 14 in synchronization with the vertical synchronization signal separated by the synchronization separator 12, and the vertical counter 161. In order to correct the vertical timing pulse generator 162 to generate a vertical timing pulse by the signal inputted by the reference signal), and to display it in the center of the image by the signal delay by the signal delay means 11, the timing of the vertical timing pulse is adjusted. Vertical timing pulse control means 163 for controlling a predetermined time, and a vertical triangular wave oscillator 164 for generating a vertical triangular wave for driving the vertical deflection portion 17 by the controlled vertical timing pulse.

Referring to Figures 2 and 3 with respect to the TV screen upper distortion correction device configured as described above is as follows.

First, assuming that a non-standard signal (video signal) is input,

When the composite video signal is applied to the signal delay means 11 and the synchronization separator 13, the signal delay means 11 delays and outputs the input video signal until the start point of horizontal scanning is stabilized. The separator 13 separates the horizontal sync and the vertical sync signals from the composite video signal.

Here, the vertical synchronization signal is disturbed by the synchronization separator 13 receiving the composite video signal by the switching section of the video head, and the phase detector of the automatic frequency controller 14 is disturbed by the disturbance of the vertical synchronization signal. (141) The voltage change is increased, and thus the oscillation frequency of the horizontal oscillator 142 is also disturbed, so that the upper portion of the screen is curved.

In this case, the signal delay means 11 converts the input composite video signal into a digital video signal by the A / D converter 111 and applies the digital signal to the storage means 112.

When the operation thereof is described in detail, the timing generating means 114 for controlling the storage means 112 is based on the vertical synchronizing signal and the horizontal synchronizing signal as shown in FIG. 3A separated from the synchronizing separator 13. By using the generated clock signal (clock) to output a write clock (WR; WWR) as shown in Figure 3 (B) to receive the digital image signal to the image storage means 112 is stored.

The signal stored in the storage means 112 is delayed for a predetermined time until the start point of the horizontal scanning is stabilized, and then a read reset signal (RR) as shown in FIG. 3C is applied from the timing control means 114. The received signal is read and stored as an analog signal through the D / A converter 113.

Here, the delay time t1 of the RR pulse of the storage means 112 is set by the automatic frequency controller 13 to a time at which the start point of the horizontal scan is located at the start point of the screen and is stabilized.

The analog video signal delayed by the predetermined time is processed by the video signal processor 12 and output as a color signal R.G.B.

At this time, when the signal read from the storage means 112 is displayed on the screen in accordance with the original vertical synchronizing signal, the position of the image signal is prevented from appearing in the form moved to the bottom of the screen, so that the image is displayed in the center The horizontal deflection control unit 16 is compensated for,

The vertical counter 161 of the vertical deflection control unit 16 counts the vertical synchronization signal separated from the synchronization separation unit 13 to the divided output of the automatic frequency control unit 14 in synchronization.

The vertical timing pulse generator 162 which receives the counting of the vertical counter 161 generates a vertical timing pulse as shown in FIG.

At this time, the vertical timing pulse control means 163 receiving the vertical timing pulse generated by the vertical timing pulse generator 162 controls and outputs the timing for a predetermined time t2 as shown in FIG. . This corrects by the delayed time (t1 = t2) in the storage means 112 of the signal delay means 11 to control the vertical timing pulse.

That is, since the difference between the rising edge ↑ of the waveform of FIG. 3D of the vertical timing pulse generator 162 and the rising edge ↑ of the waveform of FIG. 3E of the delayed vertical timing pulse is t2, Compensation will be as much as the delayed value.

The vertical triangular wave oscillator 164 generates the vertical triangular wave for driving the vertical deflection unit 17 by the vertical timing pulse controlled as described above, and the vertical deflection unit 17 is deflected by the vertical triangular wave. Is shifted, that is, vertical deflection is performed so that the image is displayed at the center.

Therefore, the automatic frequency control unit 16 delays using the storage means 112 until the start point of the horizontal scan is stabilized at the start of the vertical scan, and the screen is displayed on the screen by the delay of the storage means 112. The deflection position is shifted by delaying the vertical timing pulse in order to prevent the bias toward the bottom of the screen, thereby improving the upper curvature of the screen at the input of the non-standard signal.

According to the present invention, even when a video tape such as a VCR is worn out and a non-standard signal is input, the upper portion of the TV screen is prevented from being bent, thereby providing a clear picture quality to the viewer.

Claims (3)

Signal delay means for delaying the video signal for a predetermined time until the horizontal deflection output of the automatic frequency control unit is stabilized so as to correct an upper screen deflection; A video signal processor for processing the video signal delayed by the signal delay means to output the color signal; A synchronization separator for separating the vertical synchronization and the horizontal synchronization by receiving the composite video signal; An automatic frequency controller for controlling the frequency of the horizontal synchronization signal separated by the synchronization separator; A horizontal deflection unit which performs horizontal deflection with a signal input by the automatic frequency control unit; A vertical counter for counting the divided input signal of the automatic frequency controller in synchronization with the vertical synchronization signal separated by the synchronization separator, and a vertical timing pulse generator for generating a vertical timing pulse by a signal input through the vertical counter; A horizontal deflection control unit comprising vertical timing pulse control means for controlling a vertical timing pulse generated by the vertical timing pulse generator for a predetermined time, and a vertical deflection unit for generating a vertical triangular wave for driving a vertical deflection unit with the controlled vertical timing pulse; Wow; And a vertical deflection portion for performing vertical deflection by the vertical triangular wave. 2. The apparatus of claim 1, wherein the signal delay means comprises: an A / D converter for converting a composite analog signal into a digital signal, and receiving and storing the digital video signal according to an WR signal of a timing generator. Image storage means for outputting the stored signal to the image processing unit, a D / A converter for converting the image signal stored in the image storage means into an analog signal, and an image storage means based on the vertical synchronization signal of the synchronization separation unit. And a timing generator for generating the WR and RR signals for controlling. The apparatus of claim 1, wherein the vertical timing pulse control means controls a horizontal timing pulse for a predetermined time so that an image according to the signal delay of the signal delay means is displayed at the center.