KR20000044743A - Uniformization apparatus of outer video signal level in digital tv - Google Patents

Abstract

PURPOSE: An uniformization apparatus of outer video signal level in digital TV is provided to extract the horizontal synchronous signals of input video signals and control the signals in accordance with the levels of the extracted signals, thereby displaying clean images. CONSTITUTION: An uniformization apparatus of outer video signal level in digital TV comprises a micom(110), a tuner and demodulator(115), a MPEG decoder(120), a video encoder(125), an image synthesizer(130), a menu generator(135), a signal controller(160), a memory(165), and a signal level detection block(155) consisting of a horizontal synchronous signal divider(140), an amp(145) and a DC converter(150). The micom(110) generates tuning control signals corresponding to channel selection signals to supply them to the tuner and demodulator(115). The tuner and demodulator(115) tunes selected broadcasting channels and outputs tuned signals. The signal level detection block(155) detects the levels of the tuned signals input to the tuner and demodulator(115).

Description

External video signal level equalizer in digital television

The present invention relates to a method for adjusting the size of a video signal input to a digital TV, and more particularly, to output the same video signal level among external input signals such as terrestrial broadcast, cable broadcast, and satellite broadcast supported by a digital TV. And a video level adjusting method of a digital TV.

Digital TVs are generally capable of receiving digital satellite, cable and terrestrial broadcast signals, and dual satellite broadcasts use a satellite (communication satellite) located at an altitude of approximately tens to hundreds of kilometers above the earth's surface. In the satellite broadcasting system, a Ku band RF signal having a frequency band of 11.7 GHz to 12.0 GHz is used in the satellite broadcasting system. To this end, the antenna for satellite broadcasting reception is provided with a low noise blockdown converter for converting a radio frequency (RF) signal of a very high frequency into an intermediate frequency (IF) signal, and the low noise converter converts an ultra high frequency RF signal. It converts into an IF (intermediate frequency) signal in the hundreds to thousands of MHz bands (for example, 950 MHz-2050 MHz) that can be received by a satellite broadcasting receiver (receiver).

Therefore, in the satellite broadcasting tuner provided in the satellite broadcasting receiver (receiver), the user selects and tunes a channel selected by inputting an IF signal received through a low noise converter. The satellite broadcasting receiver maximizes channel utilization, video and audio signals. Besides the improvement of quality and the ease of transmitting additional digital service data, the significant improvement of the user interface is a big advantage.

If the subscriber (i.e., one receiver) wants to accept all broadcasting signals such as CATV broadcasting and satellite broadcasting, the frequency bands are different for each broadcasting, so the satellite broadcasting tuner, cable broadcasting tuner, and terrestrial broadcasting tuner must be separately installed. something to do.

Therefore, in order to accommodate various types of broadcasts as described above, various types of internal or external tuners may be provided, or each type of broadcasts may have separate signal processing paths (that is, satellite broadcast signal processing paths and cable broadcast signals). It may be considered that the receiver employs an integrated complex tuner for processing through the processing path, but this causes not only an unnecessary increase in hardware of the receiver itself, but also an excessive increase in the cost of the receiver. Is caused.

On the other hand, in view of the above, there is a composite tuner capable of simultaneously receiving satellite broadcast signals, cable broadcast signals, and terrestrial broadcast signals through a single tuning path, and a composite broadcast receiver incorporating such composite tuners. The composite broadcast receiver controls the passband of the received signal and tunes the bandpassed signal based on the user selection signal when a satellite broadcast signal or a cable broadcast signal is received at the input side, and according to the tuned signal and the user selection. By tuning the oscillating frequencies that occur, the corresponding channels of the desired broadcast signal are tuned, and these tuned signals are configured to be provided to corresponding demodulators through separate signal processing paths (BS path, DSR path, CATV path), respectively. have.

However, the terrestrial broadcast, satellite broadcast, and cable broadcast supported by the conventional composite broadcast receiver have differences in signal levels, respectively. As described above, there is a difference in image quality broadcast through each signal processing path. There are disadvantages. In another case, when a satellite broadcast or terrestrial broadcast is received as an input and the display is performed, the video signal level is lower than that of the non-viewing area, thereby degrading image quality.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and stores a standard video signal level corresponding to a video signal level of each broadcasting channel, extracts a horizontal synchronization signal of an input video signal, and according to the extracted signal level. It is an object of the present invention to provide a method for adjusting the video signal level of a digital TV that can display a broadcast of clear picture quality by adjusting a signal.

In order to achieve the above object, the present invention provides an external video signal level equalization device in a digital TV that can process and broadcast digital TV broadcast signals such as terrestrial broadcast signals, cable broadcast signals, and satellite broadcast signals. A tuner and a demodulator for tuning the selected broadcast channel and outputting a tuned signal, a signal level detection block for detecting a signal level of a tuned signal input to the tuner and demodulator, and a signal detected level from the signal level detection block. In the digital TV comprising a microcomputer that compares the received reference level and the signal detected level to output the comparison level information, and a signal controller for amplifying or attenuating the tuned signal according to the comparison level information received from the microcomputer Provides an external video level equalizer.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a block diagram of a digital TV implementing an external video level equalization device in a digital TV according to the present invention.

<Description of the code | symbol about the principal part of drawing>

110: microcomputer 115: tuner and demodulator

120: MPEG Decoder 125: Video Encoder

130: image synthesizing unit 135: menu generating unit

140: horizontal synchronization signal separation unit 145: amplification unit

150: DC converter 155: signal level detection block

160: signal control unit 165: memory unit

Hereinafter, a video signal level adjusting method of a digital TV according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 is a block diagram showing a digital TV suitable for implementing a video signal level adjustment method of a digital TV according to the present invention, which includes a microcomputer 110, a tuner and a demodulator 115, an MPEG decoder 120, and a video. Encoder 125, image synthesizer 130, menu generator 135, signal controller 160, memory 165 and horizontal sync signal separator 140, amplifier 145 and DC converter Signal level detection block 155 including 150, and its individual configuration and function are as follows.

When the user broadcast channel selection signal is input from the outside, the microcomputer 110 generates a tuning control signal corresponding thereto and provides the tuner and demodulator 115 to be described later.

In addition, when the user calls a menu screen, the microcomputer 110 extracts the menu configuration information constituting the menu screen from the tuner and the demodulator 115, and extracts the extracted menu configuration information to the menu generator 135. The menu screen is displayed along with the image. The microcomputer 110 stores, in particular, the reference level of the input digital TV broadcast signal in the memory unit 165 and compares it with the signal level input from the DC converter 150 of the signal level detection block 155. Print information. The output comparison level information is provided to the signal controller 160. For example, the comparison level information is provided to the user in the broadcast signal received through the broadcast signal receiver (i.e., receiving antenna), which is not shown, based on the tuning control signal provided by the tuner and demodulator 115 from the microcomputer 110. Tune to the selected broadcast channel and adjust the level of the tuned signal among the input digital TV broadcast signals under the control of the signal adjusting unit 160 according to the comparison level information input from the microcomputer 110 for the tuned signal, After the conversion to the intermediate frequency, demodulation and error correction, the transport stream is restored. The transport stream thus restored is provided to the MPEG decoder 120 of the next stage.

MPEG decoder 120 is based on the control signal provided from the microcomputer 110, the compressed and encoded audio and video signals of the broadcast channel provided from the tuner and demodulator 115, for example, the time and space of the video signal In consideration of the correlation, the compressed coded video signal is restored to the original signal before encoding using a decoding technique such as variable length decoding, inverse DCT, inverse quantization, motion compensation, and the reconstructed digital broadcast video signal Provided to video encoder 125, the reconstructed audio signal is provided to an audio signal processor, not shown.

The video encoder 125 converts the digital broadcast video signal provided from the MPEG decoder 120 to an NTSC or PAL analog video signal and then provides the video synthesizer 130 to the image synthesizer 130, and the menu generator 135. Restores the encoded various menu configuration data provided from the above-described tuner and demodulator 115, such as a broadcast channel menu service, to an original signal before encoding, and configures it as a menu screen and provides the image screen to the image synthesizer 130.

Therefore, the image synthesizing unit 130 transfers the analog broadcast signal output from the video encoder 125 to the display side (not shown) or displays a screen mixed with the menu screen and the analog broadcast signal displayed through the menu generator 135. To the display side.

The signal level detection block 155 detects the level of the tuned signal input to the tuner and demodulator 110, and provides the detected level information to the microcomputer 110, and the horizontal synchronization signal separation unit 140. ), The amplifier 145 and the DC converter 150, the individual configuration and function are as follows.

The horizontal sync signal separator 140 receives the tuned signal from the tuner and demodulator 115, separates the horizontal sync signal from the input video input signal, and extracts the separated horizontal sync signal to the amplifier 145. to provide.

The amplifier 145 receives the horizontal sync signal extracted by the horizontal sync signal processor 140 and amplifies the received signal by a predetermined multiple. The amplified signal is provided to the DC converter 150.

The DC converter 150 receiving the amplified signal from the amplifier 145 smoothes and converts the amplified synchronous signal into a DC waveform instead of a fully ringed DC waveform. The level of the converted DC waveform is read by the microcomputer 110 to detect the input signal level and provide it to the microcomputer 110.

The signal controller 160 receives the comparison level information from the microcomputer 110 to amplify the tuned signal or attenuate the tuned waveform according to the received comparison level information.

As described above, according to the present invention, by automatically adjusting the video level in response to the attenuation due to the visual acuity at the time of viewing, it is possible to output at a constant video signal level, even if the type of broadcast is changed due to a channel change, etc. There is an effect that can display the above picture quality.

Claims (2)

An apparatus for adjusting the video signal level in a digital TV that can process and broadcast digital TV broadcast signals such as terrestrial broadcast signals, cable broadcast signals, and satellite broadcast signals. A tuner and a demodulator for tuning a broadcast channel selected from the TV broadcast signal and outputting a tuned signal; A signal level detection block for detecting a signal level of the tuned signal input to the tuner and the demodulator; A microcomputer receiving the detected signal level from the signal level detection block and comparing the previously stored reference level with the detected signal level to output comparison level information; And a signal adjusting unit configured to amplify or attenuate the tuned signal according to the comparison level information recognized by the microcomputer. The method of claim 1, wherein the signal level detection block A horizontal sync signal separator for receiving a tuned signal from the tuner and the demodulator, separating a horizontal sync signal from an input video input signal, and extracting the separated horizontal sync signal; An amplifying unit which receives the horizontal synchronizing signal extracted by the horizontal synchronizing signal separation unit and amplifies the received signal by a predetermined multiple; And an external video level homogenizer for converting the amplified signal from the amplifier into a DC waveform.