KR100188220B1 - Automatic degaussing apparatus of high definition television - Google Patents

Abstract

The present invention relates to an automatic degaussing apparatus for synchronous switching of a high-definition television, the apparatus comprising: function setting means (18) for setting a key for channel switching for a general television system and an HD television system television signal; (20) for controlling switching of a predetermined broadcast channel in accordance with switching of the television system by the television system (18) and controlling the de-amplifying operation to be performed when a fluctuation state of the synchronizing signal is detected in response to the switching of the channel (22) for separating a sync signal included in a television signal of a general television system selected from the first channel selection processing means (2, 6), and a second sync separation means (26) for supplying a general synchronization detection signal generated as a result of comparing a synchronizing signal separated by the first channel selection signal and a first preset reference signal to the control means (20) (28) for separating a sync signal included in a television signal of the HD television system selected from the broadcast signals (4, 8), a sync signal demultiplexing means A second comparing means (32) for supplying an HD synchronous detection signal generated as a result of comparison with the second reference signal to the control means (20) And degaussing means (36, 38) for performing a degaussing operation on the CRT (16) in a state in which the CRT (16) is switched.

Description

Automatic degaussing device for synchronous switching of high-definition television

1 (a) shows a broadcasting signal line for a television room thd in the NTSC system; Fig.

1 (b) is a diagram showing a broadcasting signal line for a television room thd in the HD system.

FIG. 2 is a block diagram showing an automatic degaussing apparatus for synchronous switching of a high-definition television according to the present invention; FIG.

3 shows a detailed circuit configuration of the second sync separator shown in Fig. 2; Fig.

FIG. 4 is a flowchart illustrating an operation according to a preferred embodiment of the present invention.

DESCRIPTION OF THE REFERENCE NUMERALS

2,4: tuner 6,8: IF unit

10, 12: Image processing unit 14:

16: CRT 18: Function setting section

20: control unit 22, 28:

24, 30: reference signal setting unit 26, 32:

34: power supply circuit section 36: degaussing drive section

38: DiGouxing

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an automatic degaussing apparatus for synchronous switching of a high-definition television, and more particularly to an apparatus and method for simultaneously reproducing a television signal according to an HD television broadcasting system and a television signal according to a general television broadcasting (NTSC television broadcasting) The present invention relates to an automatic degaussing apparatus for synchronous switching of a high-definition television, in which a degaussing function can be automatically performed when a switching state of a broadcasting system is detected on a high-definition television having a high-definition television.

Conventionally, a general transmission system of a television, such as a National Television System Committee (NTSC) television system, which is generally used, has a form in which a luminance signal, a color difference signal, a synchronization signal, and the like are superimposed and transmitted so that a plurality of television stations Which is transmitted by an analog method, and has a screen specification according to a 4: 3 screen aspect ratio, and is generally employed in Korea, the United States, and Japan.

According to a general television system such as the NTSC television broadcasting system, as shown in FIG. 1 (a), there are about 485 effective scanning lines and 20 vertical retrace periods (or vertical blanking periods) among a total of 525 scanning lines, On the other hand, the 525-line scanning line is interlaced with two fields (field frequency: 59.94 Hz) of an even field and an odd field as one frame, A horizontal synchronizing signal for determining a horizontal retrace period (horizontal blanking period of 10.9s) that returns from the scanning of the scanning line (line frequency 15734.264Hz) until the scanning of the next scanning line is performed is superimposed per person The vertical synchronization signal is supplied to a predetermined scanning period such as three scanning periods, for example, during a period during which one field is scanned and then the scanning returns to the next field, And to be included is inserted between the equalizing pulse of the liver.

In addition, the horizontal / vertical synchronizing signal employed in such a general television system has a binary sawtooth signal form having negative polarity. On the television set side receiving the television signal, the horizontal / vertical synchronizing signal included in the television signal is So that horizontal / vertical deflection can be correctly adjusted.

On the other hand, there is an insufficient amount of realism due to a decrease in image quality due to a screen specification of 4: 3 aspect ratio and a decrease in image quality due to a picture composition of 525 scanning lines, which occurs when a general television system such as the NTSC television system is adopted In order to solve this problem, in recent years, an HD television (High Definition TV) broadcasting system has been adopted in which a high-definition image can be provided as a large screen having a screen aspect ratio of 16: 9.

According to this HD television system, as shown in FIG. 1 (b), the 2: 1 interlaced scanning is performed in the same manner as in the general television system so that two fields can constitute one frame, that is, one screen. With 1125 scan lines per frame (field frequency is 60.00Hz and line frequency is 33750Hz), the number of effective scan lines reaches 1035 lines, so that the number of pixels per frame is about five times that of general television, making it possible to reproduce more detailed images. .

On the other hand, in the horizontal / vertical synchronizing signal employed in such an HD television system, the signal has a three-valued signal form having a positive polarity, and the vertical retrace period including the double vertical synchronizing signal is a period of a general television system equivalent to 20 lines Compared with the previous year.

In addition, in a high-definition television set having an aspect ratio of 16: 9 for tuning and reproducing a television signal of the current HD television system, television signals of the NTSC television system which are currently being transmitted effectively are received at the same time, So that general television broadcasts can be reproduced.

However, in a high-definition television capable of compatible reproduction of the general television system and the HD television, the field frequency and the line frequency according to the television signal of the general television system and the television signal of the HD television system are different from each other and the horizontal and vertical blanking periods are respectively different In addition, since both the horizontal and vertical sync signals are composed of the two-value negative polarity and the three-way positive polarity, the television signal of the HD television system can be switched to the channel state or the HD television system When a television signal of the general television system is reproduced by switching the channel, it is inevitable to perform scanning with a 4: 3 aspect ratio or a 16: 9 aspect ratio. However, Horizontal / vertical deflection fluctuates due to variable frequency CRT (Cathode Ray Tube) There is a possibility that the shadow mask installed in the cathode ray tube is magnetized by the incorporation of geomagnetism, and the deflection is distorted by the generated magnetic field, The color is confused and the color purity is degraded, resulting in deterioration of image quality.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a digital broadcasting system and a digital television broadcasting system, And an automatic degaussing apparatus for synchronous switching of a high-definition television which can be automatically performed.

According to an aspect of the present invention, there is provided an automatic degaussing apparatus for synchronous switching of a high definition television according to the present invention, comprising: first channel selection processing means for selecting a television signal of a general television system and processing an intermediate frequency signal; A first image processing unit for processing the television signal of the general television system, a second image processing unit for processing the television signal of the HD television system, A high definition television having a video output unit for amplifying and outputting a television signal so as to be reproducible via a CRT, comprising: function setting means for setting a key for switching a channel for a general television system, an HD television system and a television signal; The switching of the predetermined broadcasting channel is carried out in accordance with the switching of the television system by the means And control means for controlling to perform a degaussing operation when a fluctuation state of a synchronizing signal is detected in response to the switching of the station selection, a control means for controlling the synchronizing signal included in the television signal of the general television system selected from the first station selecting means, A first synchronization separating means for separating a first synchronizing signal and a second synchronizing signal which are generated by comparing a synchronizing signal separated by the first synchronizing separating means with a preset first reference signal, Second synchronizing means for synchronizing signals included in the television signal of the HD television system selected from the second channel selection processing means, synchronizing means for synchronizing the synchronizing signal separated by the second synchronizing means with a preset second Second comparing means for supplying an HD synchronous detection signal generated as a result of comparison with the reference signal to the control means; There is provided an automatic degaussing apparatus for synchronous switching of a high-definition television, which comprises a degaussing unit for performing a degaussing operation on the CRT by a state in which a television system of a television signal is switched.

According to the present invention configured as described above, in a high-definition television capable of both switching between a normal television type television signal and an HD television type television signal, When the switching state of the synchronizing signal included in the television signal to be switched is detected by the switching of the channel to the broadcasting channel of the television signal to be switched to the corresponding channel, As shown in FIG.

Hereinafter, the present invention configured as described above will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram showing an automatic demosaicing apparatus for synchronous switching of a high definition television according to the present invention. In the apparatus of the present invention, reference numeral 2 denotes an NTSC 4 shows a television tuner according to the HD television system selected by tuning control from the control unit 20, which will be described later, And converts it into an intermediate frequency signal.

Reference numeral 6 denotes a first intermediate frequency amplifier for amplifying a television signal of a general television system selected through the first tuner 2 (i.e., a video signal), and 8 denotes a second tuner 4 (That is, a video signal) of the HD television system selected through the first intermediate frequency amplifying unit.

Reference numeral 10 denotes a video signal synthesizing apparatus for synthesizing a composite video signal by performing signal amplification of the video signal of the intermediate frequency amplified general television system and separating the luminance signal and the color difference signal thereby adjusting the luminance of the luminance signal and demodulating the color difference signal. And the first image processing unit performs image processing.

Reference numeral 12 denotes a sampling circuit for sampling a video signal of the HD television system through the second intermediate frequency amplifier 8 and converting the sampled video signal into digital data and then performing a luminance adjustment of the luminance signal and a demodulation operation of the color difference signal, And a second image processing unit for performing image processing.

Reference numeral 14 denotes a multiplexer for multiplexing the composite video signal according to the general television system from the first video processor 10 or the composite video signal according to the HD television system from the second video processor 12, And outputs it to reproduce through the CRT 16 having the aspect ratio.

Reference numeral 18 denotes a remote controller for remote control or a matrix button unit provided in the control panel unit of the main body so that a broadcast channel assigned to a television signal of a general television system or a broadcast channel assigned for a television signal of an HD television system is selected And a function setting unit for performing a key operation for switching.

Reference numeral 20 denotes a control unit for controlling the overall functional operation of the high-definition television. The control unit 20 controls the general television system from the function setting unit 18 or a broadcast channel based on the television signal of the HD television The channel selection data for channel selection of a channel to be selected for channel selection is applied to the first tuner 2 or the second tuner 4, A general sync detection signal according to a result of detecting a binary sync signal according to the general television system from the unit 26 or a sync signal having a three-value according to the HD television system from a second comparator 32 The demosaicing unit 38 controls the demosaicing unit 38 to perform a demosaicing function.

Reference numeral 22 denotes a first sync separator for separating a sync signal contained in a television signal according to the selected general television system, 24 denotes a first reference signal corresponding to a binary sync signal according to a general television system Reference numeral 26 denotes a first reference signal setting unit which is set in advance in accordance with a result of comparison of the synchronization signal of the general television system from the first synchronization separator 22 on the basis of the preset first reference signal, Signal to the control unit 20 side.

In addition, reference numeral 28 denotes a second sync separator for separating a sync signal included in the television signal according to the selected HD television system, and the second sync separator 28 separates A pedestal clamp circuit 40 for clamping the video signal according to the HD television system from the second intermediate frequency amplifier 8 in accordance with the pedestal level, and a zero cross pulse A first comparator 42 for detecting a cross pulse of the video signal, an LPF 44 for low-pass filtering the video signal, a peak clamp circuit 46 for clamping the peak of the synchronous front end in the low-pass filtered signal component, A second comparator 48 for detecting a negative pulse in the signal pulse, a monostable multivibrator 50 for receiving the detected negative pulse and generating a gate pulse, To And an equalizing pulse removing unit 54 for removing a remaining equalizing pulse in the generated reference timing pulse to obtain a horizontal synchronizing signal, .

Reference numeral 30 denotes a second reference signal setting unit in which a second reference signal corresponding to a three-value synchronizing signal according to the HD television system is previously set. Reference numeral 32 denotes a second synchronous separation And generates a HD sync detection signal to the control unit 20 as a result of a comparison of a sync signal (i.e., a horizontal sync signal)

Reference numeral 36 denotes a control unit which is driven by the control unit 20 to supply operating power from the power supply circuit unit 34 to the degaussing unit 38 so that the degaussing operation of the CRT 16 is performed And a degaussing drive unit.

The operation of the present invention as described above will now be described in detail with reference to the accompanying drawings.

First, in a high-definition television capable of compatible reproduction of signals of a general television system and an HD television system television, a television signal of a general television system is transmitted through the first tuner 2 by a channel selection operation of the function setting unit 18 The video signal of the HD television system amplified by the first intermediate frequency amplifier 6 by the first intermediate frequency amplifier 6 is processed through the first video processor 10 in the form of a composite video signal and output to the video output unit 14 The first sync separator 22 separates the sync signal included in the video signal of the general television system and the first comparator 26 separates the sync signal included in the video signal of the general television system into a binary sync signal As a result of the comparison of the separated synchronizing signals on the basis of the first reference signal from the corresponding first reference signal setting section 24, a general synchronizing detection signal indicating the detection of the synchronizing signal in accordance with the binary television system is generated to do do.

Accordingly, the control unit 20 receives the general synchronization detection signal from the first comparison unit 26, and recognizes that the television signal of the general television system is being reproduced in the outgoing signal state.

In this state, when the function setting section 18 performs a key operation for switching the channel to a broadcast channel according to a television signal of the HD television system, and the television signal of the corresponding channel is selected through the second tuner 4 The second sync separator 28 clamps the video signal of the HD television system through the second intermediate frequency amplifier 8 to the pedestal level in the pedestal clamp circuit 40, The zero crossing pulse is obtained through the second comparator 42. When the peak value of the synchronization end is clamped through the peak clamp circuit 46 after the low pass filtering of the video signal by the LPF 44, The negative pulse is obtained and the gate pulse is generated by the monostable multivibrator 50 while the AND gate 52 performs the logical multiplication of the negative pulse through the gate pulse to generate the reference timing pulse, The pulse elimination (5 A horizontal synchronizing signal in which equalization pulse components are removed is obtained.

The second comparator 32 compares the synchronizing signal (i.e., the horizontal synchronizing signal) separated by the second synchronizing separator 28 based on the second reference signal preset in the second reference signal setting unit 30, As a result, an HD synchronous signal having a three-level synchronous signal is generated.

The controller 20 drives the degaussing driver 36 as a result of receiving the HD synchronous detection signal from the second comparator 32 so that the degaussing unit 38 can be driven by the CRT 16, So that it can perform the degaussing operation on the data.

On the other hand, in the present invention having the above-described embodiment, even when HD television system television signals are selected and reproduced, switching to a television signal of a general television system is performed again, the general synchronous detection signal The automatic degaussing operation by the degaussing unit 38 can be performed.

According to the present invention as described above, when the switching state of the synchronizing signal is detected by switching the channel from the high-definition television to the television signal of the general television system or to the television signal of the HD television system, It is advantageous in that high quality broadcast reproduction can be achieved by preventing deterioration of image quality caused by frequency fluctuation and geomagnetism caused by switching of the television system.

Claims (1)

A first channel selection processing means (2, 6) for selecting a television signal of a general television system and processing the signal by an intermediate frequency, a second channel selection processing means (4, 8) for selecting a television signal of the HD television system for intermediate frequency processing, A first image processing unit 10 for processing a television signal of a general television system, a second image processing unit 12 for processing a television signal of the HD television system, And a video output unit (14) for amplifying and outputting the video signal so as to be reproducible. The high definition television comprises function setting means (18) for setting a general television system, an HD television system, A predetermined broadcast channel is switched according to the channel selection switching of the television system by the setting means 18 and when the fluctuation state of the synchronizing signal is detected in response to the channel switching, (22) for separating a sync signal included in a television signal of a general television system pre-processed from the first channel selection processing means (2, 6), a control means And first comparing means for supplying a general synchronizing detection signal generated as a result of comparing the synchronizing signal separated by the first synchronizing separating means 22 with a preset first reference signal to the controlling means 20 26), a second sync separating means (28) for separating a sync signal contained in a television signal of an HD television system selected from the second channel selecting means (4, 8), a second sync separating means A second comparing means 32 for supplying an HD synchronous detection signal generated as a result of comparing the synchronizing signal separated through the first synchronizing signal to a predetermined second reference signal to the control means 20, The television system of the television signal selected under control is switched By state degaussing means (36,38) automatically degaussing apparatus when synchronous switching of the high-definition television, characterized in that configured by comprising a performing a degaussing operation for the CRT (16),