KR100250681B1 - Sync. signal converting control apparatus for multi-image television - Google Patents

Abstract

PURPOSE: An apparatus for controlling synchronous switch of a multi-screen TV is to control signal distribution to use a synchronizing signal including a TV broadcasting signal as synchronizing information, when reproducing broadcasting programs of a plurality of channels on the multi-screens. CONSTITUTION: An AGC(automatic gain control) portion(12,14) detects a signal gain value with respect to a plurality of TV broadcasting signals selected by each channel selecting portion, and generates an AGC voltage to compensate each signal gain value. A synchronous separating portion(20,22) separates and extracts a synchronizing signal component included in the TV broadcasting signals of the plurality of channels. A synchronous switching portion(24) performs a switching operation for supplying the synchronizing signal corresponding to a stable AGC voltage to a video signal processing portion(16,18). And a controlling portion(32) receives the AGC voltage from the AGC portion to detect the AGC voltage included in a predetermined reference voltage level and controls the synchronous switching portion so that the synchronizing signal corresponding to the AGC voltage is supplied to the video signal processing portion.

Description

Synchronous switching controller of multi-screen television

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous switching control apparatus for a multi-screen television. More particularly, in a multi-screen television capable of simultaneously reproducing a multi-channel broadcast program on a multi-screen, the most stable broadcasting among the synchronization signals included in the multi-channel television signal A synchronous switching control apparatus for a multi-screen television which makes it possible to utilize a synchronous signal for a signal as synchronous information according to an overall multi-screen reproduction process.

Conventionally, in order to reproduce a video / audio through a CRT and a speaker through a medium frequency conversion / amplification process and a video / audio signal process by selectively selecting a single broadcast channel among a plurality of channels transmitted from a plurality of television broadcasting stations, respectively. In a typical single-screen television adopted, a single tuner is provided and a single broadcast screen by a single CRT screen can be reproduced. Thus, when a broadcast screen of one channel is reproduced, a broadcast of the other channel is performed. It is not possible to view the program or check the broadcast status.

In order to solve the problem caused by the conventional television which can reproduce only a single screen, recently, a plurality of tuners are provided so that a plurality of broadcast channels can be tuned at the same time. Through the video / audio signal processing, a plurality of sub-images can be reproduced on a single main image, and the audio signal can be selectively switched through a speaker and a headphone terminal. PIP (Picture In Picture) function is adopted to output.

In addition, a two-screen playback function that can be simultaneously reproduced on two screens having the same screen area for a plurality of channel video signals tuned through such a plurality of tuners is also employed.

On the other hand, in a television having a multi-screen playback function such as a PIP function or a 2-screen playback function, a synchronous clock is required for sampling and memory storage for compression processing of a video signal determined as a playback target of a sub-screen and restoring a color signal. The determination of the synchronization signal period for extracting the color subcarrier signal for the horizontal or vertical synchronization signal extracted from the television broadcast signal determined as the reproduction target of the main screen or the synchronization signal necessary for vertical / horizontal deflection driving of the CRT screen. Based on the synchronization signal period obtained by the synchronization signal obtained from the television broadcast signal adopted as the reproduction target of such a main screen, the main / sub picture or the second screen playback function according to the PIP function can be used. The scanning period and the vertical / horizontal deflection drive processing of the first and second screens can be adjusted.

However, in such a multi-screen television, the image data sampling and compression processing for the entire main / sub picture (two screens), the adjustment of the scan period, and the vertical are based on the synchronization signal according to the television broadcast signal adopted as the reproduction target of the main screen. Because it can be used as the synchronization information for the overall reproduction processing operation such as the horizontal deflection driving process, when the TV broadcast signal adopted as the reproduction target of the main screen becomes unstable due to internal / external factors The sync signal included in the television broadcast signal is also unstable, which adversely affects the overall reproduction processing operation.

Accordingly, the present invention has been made in view of the above circumstances, and includes a television broadcast signal having the best signal gain by AGC (Automatic Gain Control) means when multi-screen playback of a multi-channel broadcast program is performed. It is an object of the present invention to provide a synchronous switching control device for a multi-screen television for controlling signal distribution so that the synchronous signal can be utilized as synchronous information for signal processing of the entire multi-screen.

In order to achieve the above object, according to the synchronous switching control apparatus for a multi-screen television according to the present invention, a plurality of channels of television broadcast signals tuned by a plurality of tuning means are processed by a plurality of video signal processing units, respectively. In a multi-screen television which is capable of screen reproduction by means of a screen, a plurality of signal gain values for a plurality of television broadcast signals tuned from the respective tuning means are detected to generate AGC voltages for compensation control for each signal gain value, respectively. AGC means, a plurality of synchronization separating means for separating and extracting the synchronization signal components included in the plurality of television broadcast signals, respectively, and the plurality of AGC means among the respective synchronization signals separated from the plurality of synchronization separating means. Synchronization of the television broadcast signal corresponding to the AGC voltage whose voltage value is stable at the AGC voltage from the A synchronous switching means for performing a switching operation for supplying a call to the plurality of video signal processing units, and AGC voltages received from AGC voltages from the plurality of AGC means, respectively, and detecting an AGC voltage included in a preset reference voltage level value, Provided is a synchronization switching control apparatus for a multi-screen television, comprising control means for switching and controlling the synchronization switching means so that synchronization signals from television broadcast signals corresponding to AGC voltages are respectively supplied to the plurality of video signal processing sides.

According to the present invention configured as described above, AGC voltage for gain compensation for the television broadcast signal of each broadcasting channel in a multi-screen television that simultaneously reproduces in multiple screens on the television broadcasting signal of a plurality of channels tuned from a plurality of tuners, respectively Is compared with a predetermined reference voltage level, and a synchronous signal separated from a television broadcast signal with stable signal gain is supplied to a plurality of video signal processing means for multi-screen signal processing, so that synchronous information for sampling and data compression of the video signal is obtained. It can be used as.

1 is a block diagram showing a state in which a synchronous switching control device according to the present invention is applied to a multi-screen television;

FIG. 2 is a circuit diagram illustrating a detailed configuration of the synchronization switching unit shown in FIG. 1 in accordance with a preferred embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

2, 4: tuner, 6, 8: video IF section,

10: multi-screen mode switching unit, 12, 14: AGC unit,

16: first video signal processor, 18: second video signal processor,

20,22: Synchronous separator, 24: Synchronous switch,

26: multi-screen positioning, 28: video output,

30: function setting section, 32: control section,

34,36: transistor, 38, 40: oragate.

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

1 is a block diagram showing a state in which the synchronous switching control device according to the present invention is applied to a multi-screen television. In the apparatus of the present invention, reference numerals 2 and 4 denote multi-screen reproduction modes from the control unit 32 described later. In this case, a plurality of channel tuning data for simultaneously tuning a plurality of channels are received, and the corresponding broadcasting channel is tuned separately, and mixed with a local oscillation frequency signal generated by each channel tuning data in the form of an intermediate frequency signal. The first and second tuners to be converted are shown, and 6 and 8 represent first and second video IF portions which are respectively tuned to each other and are subjected to video intermediate frequency amplification processing of a multi-channel television broadcast signal having a form of an intermediate frequency signal.

Also, reference numeral 10 denotes a multi-screen which forms a signal path for processing the video signal as the reproduction target of the main screen and the sub-screen, respectively, for the video signals from the selected multi-channel television broadcast signals in the multi-screen playback mode. The mode switching unit is shown.

Further, reference numerals 12 and 14 detect signal gain values for the video signals of a plurality of channels which are respectively applied as reproduction targets of the main / sub picture through the multi-screen mode switching unit 10, i. First and second AGC voltages G1 and G2 for compensating a signal or a strong signal state, and generate the first and second AGC voltages G1 and G2 to the first tuner / image IF unit 2 and 6 and the second tuner / image IF unit 4 and 8, respectively. The 1st and 2nd AGC part to apply, respectively is shown.

Further, reference numeral 16 carries out luminance adjustment and color demodulation processing for the video signal according to the playback object of the main screen which has passed through the multi-screen mode switching section 10, and also passes through the synchronization switching section 24 described later. A first video signal processing section which performs sampling and compression processing of the video signal on the basis of a synchronous clock obtained by a normal synchronous signal, and 18 denotes a sub picture reproduction target which has passed through the multi-screen mode switching section 10; A second video signal processing unit which performs luminance adjustment and color demodulation processing on the video signal, and performs sampling and compression processing of the signal based on the synchronization clock by the normal synchronization signal passed through the synchronization switching unit 24 described later. Indicates.

In addition, reference numeral 20 denotes a first synchronous separator that separates and extracts a synchronous signal (ie, a composite synchronous signal component) included in a video signal as a main picture reproduction object applied to the first video signal processor 16, 22 denotes a second synchronous separator which separates and extracts a synchronous signal from a video signal serving as a sub picture reproduction object applied to the second video signal processor 18.

In addition, reference numeral 24 is switched by controlling the signal level of the switching control signal CS applied from the control unit 32 to be described later, and AGC voltages G1 and G2 obtained from the first and second AGC units 12 and 14, respectively. , The synchronization signal from the video signal corresponding to the AGC voltage corresponding to the stable voltage value whose voltage value for compensating the weak signal or the strong signal state does not exceed a predetermined set voltage value is the first and second video signal processor 16, 18 shows a synchronous switching section for performing a selective switching operation to the first synchronous separating section 20 or the second synchronous separating section 22 so as to be supplied to the 18) side.

Here, as shown in FIG. 2, the synchronous switching unit 24 has a high level switching control signal from the control unit 32, whose collector end is connected to the output end of the first synchronous separation unit 20. A first transistor 34 made of an NPN transistor which forms a signal path for the synchronization signal from the first synchronous separation unit 20 as the CS is applied to the base end and is biased and conducted, and the emitter end The second synchronous separation unit is connected to the output terminal of the second synchronous separation unit 22 and is supplied with a low level switching control signal CS from the control unit 32, which will be described later, to be biased and conducted. The second transistor 36, the output signal from the emitter end of the first transistor 34, and the collector of the second transistor 36, the PNP transistor forming a signal path for the synchronization signal from the unit 22; From Emitter stage of the first transistor and the first or gate 38 for receiving the output signal of the input signal and the logic sum processing, and supplies the synchronization signal generated according to the result to the first image signal processing unit 16 side; A first o-gate for receiving the output signal from the output signal from the collector terminal of the second transistor 36 and performing logical sum processing to supply a synchronization signal generated according to the result to the second image signal processor 18 It comprises 38.

Reference numeral 26 denotes an operation for designating the screen reproduction area of the main / sub picture for the video signal according to the main / sub picture processed by the first and second video signal processing units 16 and 18, respectively. 28 shows an image output unit which amplifies and outputs an image signal to which a screen reproduction area for the main / sub-screen is designated, respectively, so as to reproduce the image on a video screen.

Further, reference numeral 30 denotes a matrix button unit provided in a remote control unit for remote control or a control panel of the main unit, and mode switching to a multi-screen playback mode that enables simultaneous playback of main / sub picture and playback on each main / sub picture. A function setting section for performing key operation for selecting a broadcast channel to be used and for switching a zoom / T screen position.

Reference numeral 32 denotes a control unit which performs a plurality of broadcast channel tuning, overall / sub picture image signal processing, and overall function control related to screen reproduction in accordance with a key operation according to the multi-screen reproduction mode from the function setting unit 30. The controller 32 receives the first and second AGC voltages G1 and G2 generated from the first and second AGC units 12 and 14, and compares the reference voltage level with a predetermined reference voltage level. To prevent the synchronization signal of the video signal corresponding to the AGC voltage (that is, the AGC voltage for compensating the gain of the strong signal or the weak signal) from being applied as the synchronization information, and to correspond to the stable AGC voltage included in the reference voltage level. The switching control signal CS having a high level or a low level is applied to the synchronization switching unit 24 so that the synchronization signal from the video signal is applied as the synchronization information.

Next, the operation of the present invention made as described above will be described in detail with reference to FIGS. 1 and 2.

First, when the multi-screen playback mode is set by the key operation of the function setting unit 30 while the main power of the multi-screen television is turned on, and a plurality of broadcast channels for main / sub picture playback are selected, the control unit 32 Is applied to channel tuning data for tuning of a plurality of broadcast channels to the first and second tuners 2 and 4, and are tuned through the first and second tuners 2 and 4, respectively. The multi-channel television broadcast signal amplified by the video intermediate frequency by the video IF unit 6 and 8 is designated and output via the multi-screen mode switching unit 10 as the screen reproduction target of the main and sub-screens, respectively.

In this state, the first and second synchronization separators 20 and 22 are connected to the main and sub-screens applied to the first and second image signal processing units 16 and 18 through the multi-screen mode switching unit 10. The synchronous signal is separated from the video signal of the television broadcast signal, and the first and second AGC units 12 and 14 are connected to the video signal according to the main / sub picture which has passed through the multi-screen mode switching unit 10, respectively. The first and second AGG voltages G1 and G2 are generated to detect the signal gain state and compensate the signal gain.

Accordingly, the control unit 32 receives the first and second AGC voltages G1 and G2 from the first and second AGC units 12 and 14 and compares it with a preset reference voltage level. When the voltage G1 exceeds the reference voltage level and a state in which the voltage level with respect to the second AGC voltage G2 is included in the reference voltage level is detected, the low-level switching control signal is sent to the synchronization switching unit 24. (CS) is generated.

As a result, the first transistor 34 of the synchronization switching unit 24 receives the low level switching control signal CS from the control unit 32 at its base end and maintains the non-conduction state. As the second transistor 36 is biased by the low level switching control signal CS and conducts, the signal for the synchronization signal from the video signal according to the sub-screen separated from the second synchronization separator 22. The path is formed and supplied to the first and second image signal processing units 16 and 18 through logical sum processing from the first and second orifices 38 and 40, respectively.

Therefore, the first and second video signal processing units 16 and 18 can normally perform sampling and compression processing on the signal by using the synchronization signal from the video signal according to the stable sub picture as the synchronization information.

On the other hand, if it is determined that the voltage level of the first AGC voltage G1 among the first and second AGC voltages G1 and G2 is included in the reference voltage level, the control unit 32 performs The synchronization switching unit may be configured to supply a synchronization signal separated from an image signal of a corresponding main screen to the first and second image signal processing units 16 and 18 regardless of whether or not a voltage level is applied to the second AGC voltage G2. 24).

According to the present invention made as described above, in the case where the multi-channel television is tuned through a plurality of tuners in order to reproduce the main / sub picture of each channel, the AGC voltage for each television broadcast signal is decreased. Since a synchronization signal from a television broadcast signal having a normal voltage level can be supplied as synchronization information for video signal processing of a main / sub picture, a normal signal even if one broadcast signal is unstable among a plurality of broadcast channels. Value can be supplied with the synchronization information, thereby achieving stabilization of multi-screen reproduction.

Claims (2)

A plurality of channels of TV broadcast signals tuned by a plurality of tuning means (2, 6) (4, 8) are processed through a plurality of video signal processing units (16, 18), respectively, so as to enable multi-screen playback. In multi-screen television, Signal gains for the plurality of television broadcast signals tuned from the respective tuning means (2, 6) (4, 8) are detected to generate AGC voltages (G1, G2) for compensation control for each signal gain, respectively. A plurality of AGC means 12 and 14, A plurality of synchronous separation means (20, 22) for separating and extracting synchronous signal components included in the plurality of television broadcast signals, respectively; A television broadcast signal corresponding to an AGC voltage whose voltage value is stable at AGC voltages G1 and G2 from the plurality of AGC means 12 and 14 among the respective synchronization signals separated from the plurality of synchronization separating means 20 and 22. Synchronous switching means (24) for performing a switching operation for supplying a synchronous signal of the plurality of video signal processing units (16, 18) to AGC voltages G1 and G2 from the plurality of AGC means 12 and 14, respectively, are applied to detect an AGC voltage included in a preset reference voltage level value, and a synchronization signal from a television broadcast signal corresponding to the AGC voltage. And control means (32) for switching and controlling the synchronous switching means (24) such that is supplied to the plurality of video signal processing units (16, 18), respectively. 2. The synchronous switching means (24) according to claim 1, wherein the synchronous switching means (24) are connected to the output ends of the plurality of synchronous separation means (20, 22), respectively, according to the signal level of the switching control signal generated from the control means (32). A plurality of transistors 34 and 36 which perform opposite conduction states and a synchronous signal applied from output terminals of the plurality of transistors 34 and 36 are commonly applied to each other to perform logical sum processing to perform the logical sum processing. 18. A synchronous switching control apparatus for a multi-screen television, comprising a plurality of orifices 38 and 40 respectively supplied to the 18) side.

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