KR19980049352U - AGC voltage regulator for multi-channel TV tuning - Google Patents

Abstract

The present invention adjusts and controls the voltage value of the AGC voltage supplied to the tuner synchronously to each broadcasting channel during the high-speed tuning of multiple channels through a single tuner in a multi-screen television, so that the AGC voltage suitable for the broadcasting channel can be supplied. An AGC voltage regulating device is provided for multi-channel tuning of a multi-screen television.

Accordingly, the present invention generates the AGC voltage for gain control of the tuner 4 for high-speed tuning of multiple channels according to the multi-screen playback function and the broadcast signal of the multiple channels through the image IF unit 6, thereby generating the tuner ( 4) the main / sub picture signal processor 12 for processing the video signal of the main / sub picture signals according to the main / sub picture through the mode switch unit 10 according to the AGC unit 8 applied to the multi-screen reproduction function. 14) A multi-screen television having a screen position designation unit 16 for outputting the main / sub picture signal to a video output unit 18 by designating a screen position according to a main / sub picture. Synchronous counting units 20 and 22 for counting synchronous signals separated from the main video signal according to the present invention, tuning data memory 26 for storing channel tuning information for channel tuning for a plurality of broadcast channels, and executing a multi-screen playback function. According to the tuning information of the tuning data memory 28 according to the In addition to applying the tuning data for the multi-channel high-speed channel to (4), it is synchronous to the high-speed channel switching for the multi-channels of the tuner 4 based on the count values of the synchronous counting units 20 and 22. The microcomputer 28 adjusts and adjusts the voltage value with respect to the AGC voltage from the AGC unit 8 to each broadcasting channel, and the AGC from the AGC unit 8 by the control of the microcomputer 28. It is characterized in that it is provided with a voltage adjusting unit 30 for adjusting the voltage value of the voltage for each broadcast channel.

Description

AGC voltage regulator for multi-channel TV tuning

The present invention relates to an AGC voltage adjusting device for multi-channel TV tuning, and more particularly, when a plurality of channels for main / sub picture reproduction are tuned at high speed through a single tuner, the broadcasting channels are tuned to each other. The present invention relates to an AGC voltage regulating device for multi-channel TV tuning of a multi-screen television to control AGC (Automatic Gain Control) voltage synchronously so that gain control of a broadcast signal of a corresponding channel can be accurately performed.

Nowadays, in a television which is generally used, a television broadcast signal of a predetermined channel is tuned through a tuner among a plurality of television broadcast signals from a television broadcasting station that is dismissed through an antenna, and then processed. Video is output through the audio signal through the speaker.

Here, according to the tuning system for broadcasting channels such as tuners, VHF (Very High Frequency) for 12 channels such as VHF high band of 90 to 108 MHz and VHF low band of 170 to 222 MHz including video information and audio information Channel broadcasting signal and TV broadcasting signal of 50 UHF (Ultra High Frequency) channel such as 470-770 MHz UHF band are not only tunable, but also unnecessary signal from input circuit connected to receiving antenna The amplification operation is performed to improve the SN (Signal To Noise) ratio through the high frequency amplification circuit, and to match the input impedance of the high frequency amplification. In order to generate and convert to a form, a local oscillation signal whose frequency is set according to a desired channel and a broadcast RF signal according to the desired channel are heterodyned. The.

In addition, in such a television, an image amplification output is fluctuated due to a weakening in radio waves caused by a television broadcast signal induced in the reception antenna, thereby reducing the problem of changing the contrast of the screen. According to the signal strength, the AGC circuit for controlling the gain of the receiver is employed. According to this AGC circuit, if the signal strength of the input television broadcast signal is strong, the gain of the tuner and the intermediate frequency amplifier is lowered, and the signal of the television broadcast signal is reduced. If the intensity is low, the gain of the tuner and the intermediate frequency amplifier is increased so that the image detection output does not change according to the signal strength.

On the other hand, in the function of controlling the gain through the AGC circuit, the gain is increased or decreased by increasing or decreasing the collector current of the transistors in the high frequency amplifier circuit and the intermediate frequency amplifier constituting the tuner. In the AGC circuit applying the AGC voltage, the horizontal synchronization signal of the television broadcast signal is detected and detected, and the detected voltage is used as the AGC control voltage. An AGC voltage in the form of a high frequency signal is applied to the high frequency amplification part of the tuner. The intermediate frequency amplifier is applied with AGC voltage in the form of intermediate frequency signal.

However, when a gain compensation control function for a broadcast signal of a channel selected by using the AGC circuit is applied to a multi-screen television capable of simultaneously reproducing main / sub picture by operating a single tuner at a high speed so that multiple channels can be tuned. Since the AGC voltage is generated synchronously with the high-speed channel operation of a plurality of channels, it is difficult to properly execute the gain control for the broadcast signal of each channel, which is disadvantageous in that it has a rather adverse effect in the signal processing of the broadcast signal.

Accordingly, the present invention has been made in view of the above-described circumstances, and in multi-screen televisions, when a multi-channel high-speed channel is tuned through a single tuner, the voltage value of the AGC voltage supplied to the tuner synchronously is adjusted and controlled. It is an object of the present invention to provide an AGC voltage adjusting device for multi-channel tuning of a multi-screen television that enables supply of an AGC voltage suitable for a broadcasting channel.

In order to achieve the above object, according to the AGC voltage adjustment apparatus for multi-channel TV tuning according to the present invention, a tuner for high-speed tuning of multiple channels according to the multi-screen playback function, and a multi-channel broadcast signal through the video IF unit The AGC unit generates an AGC voltage for gain control and applies it to the tuner, and the main and sub-images process the main and sub-video signals according to the main and sub-screens through the mode switch unit according to the multi-screen playback function. A multi-screen television comprising a signal processing unit and a screen position designating unit for outputting the main / sub picture signal according to the main / sub picture to a video output unit, wherein the synchronization is separated from the main video signal according to the main picture. A synchronous counting unit for counting signals, a tuning data memory storing tuning information for channel tuning for a plurality of broadcast channels, and execution of a multi-screen playback function On the basis of the tuning information of the preset tuning data memory, the tuning data for the high-speed tuning of multiple channels is applied to the tuner, and the synchronization of the high-speed tuning of the multiple channels of the tuner is based on the counting value of the synchronous counting unit. The microcomputer adjusts and adjusts the voltage value of the AGC voltage from the AGC unit appropriately for each broadcasting channel, and the voltage value of the AGC voltage from the AGC unit is switched for each broadcasting channel by adjustment control of the microcomputer. Provided is an AGC voltage adjusting device for multi-channel tuning of a multi-screen television having a voltage adjusting unit for adjusting.

According to the present invention configured as described above, in a multi-screen television capable of simultaneous playback of main and sub-screens, when a plurality of channels are fast tuned through a single tuner by executing the multi-screen playback function, the tuned broadcast channel is selected. It is possible to adjust the voltage value of the AGC voltage applied for the voltage gain control for each broadcasting channel so that the image processing by the optimal channel selection is possible.

1 is a block diagram showing an AGC voltage adjusting device for multi-channel tuning of a multi-screen television according to the present invention.

Explanation of symbols on the main parts of the drawings

2: receiving antenna, 4: tuner,

6: Video IF part, 8: AGC part,

10: mode switch unit, 12: main video signal processing unit,

14: sub-video signal processing section, 16: screen position indicator,

18: video output unit, 20: synchronous separation unit,

22: synchronous counter, 24: function setting section,

26: tuning data memory, 28: microcomputer,

30: voltage adjusting section, 32: driving element (transistor).

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

That is, Fig. 1 is a block diagram showing an AGC voltage adjusting device for multi-channel tuning of a multi-screen television according to the present invention. In the device of the present invention, reference numeral 4 denotes an automatic channel search or predetermined time from the microcomputer 28 described later. When the channel is tuned, band data (VL, VH, U) and channel tuning data (TU) indicating a VHF low band, a VHF high band, or a UHF band for each broadcast channel applied to the channel are received and received by the reception antenna 2. In addition to tuning the RF signal of the corresponding channel in a plurality of broadcasting channels, the AGC voltage generated by the AGC unit 8 to be described later and regulated by the voltage adjusting unit 8 is used for the propagation of the RF signal of each broadcasting channel. The gain is controlled, and a tuner for mixing the local oscillation frequency signal generated by the channel tuning data TU and outputting it in the form of an intermediate frequency signal.

Also, reference numeral 6 denotes an image IF unit which amplifies the video intermediate frequency of the selected multiple channel television broadcast signal, and 8 denotes an AGC voltage for gain control for the intermediate frequency amplified multiple channel video signal. An AGC part is shown.

In addition, reference numeral 10 denotes a mode switch unit which is switched to enable main / sub picture reproduction for broadcast signals of a plurality of channels by mode switching control according to execution of the multi-screen reproduction function by the microcomputer 28 described later.

In addition, reference numeral 12 denotes a main image signal processing unit which processes the image signal of one channel through the mode switch unit 10 as a main image signal corresponding to the main screen, and 14 denotes the mode switch unit 10. A sub-video signal processing unit which processes a video signal of another channel through a video signal as a sub-video signal to be reproduced on the sub-screen.

Also, reference numeral 16 designates a screen playback position so that the main / sub video signals processed by the main video signal processor 12 and the sub video signal processor 14 can be reproduced through the main / sub picture, respectively. 18 shows an image output unit which amplifies the main / sub video signal to which the screen position is designated and outputs the image through a CRT (not shown) to perform horizontal / vertical deflection driving.

Reference numeral 20 denotes a synchronization separator for separating the synchronization signal included in the main image signal processed by the main image signal processing unit 12, and 22 denotes the counted result of the separated synchronization signal. It represents a synchronous counter that generates a counting output accordingly.

Further, reference numeral 24 is composed of a matrix button unit provided in a predetermined portion of a remote controller for remote control or the main body of the main body, and executes a key setting operation to execute a multi-screen playback function for main / sub picture playback for a multi-channel television program. The function setting unit is shown.

Also, reference numeral 26 denotes a tuning data memory in which band data (VL, VH, U) and channel tuning data (TU) for a plurality of broadcasting channels are stored, and 28 denotes an overall function operation assigned to a multi-screen television. As a microcomputer in charge of the control, the microcomputer 28 performs band data (VL, VH, U) and channel tuning data of the channel data memory 26 when the multi-screen playback function is executed by the function setting unit 24. Multi-channel band data and channel tuning data to be reproduced on the main / sub picture at (TU) to the tuner 4 and are switched on the basis of the count value from the synchronization counter 22. Synchronously with the state, an adjustment control signal is generated which controls the state in which the voltage value for the AGC voltage from the AGC unit 8 is voltage adjusted to suit each broadcasting channel.

Further, reference numeral 30 receives an adjustment control signal from the microcomputer 28 and adjusts the AGC voltage for the plurality of channels from the AGC unit 8 synchronously to the switching state of each broadcasting channel to adjust the tuner ( 4. The AGC connected to the collector stage by varying the bias state by the voltage value of the adjustment control signal from the microcomputer 28 applied through the base end. And a driving element 32 made of, for example, an NPN transistor for adjusting the voltage value of the AGC voltage applied between the output terminal of the section (8) and the AGC input terminal of the tuner 4.

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

First, as the main / sub picture reproducing function is executed by the function setting unit 24 and a plurality of channels are selected, the microcomputer 28 selects the band data (VL,) for the plurality of broadcasting channels from the channel data memory 26. VH, U) and channel tuning data (TU) read band data and channel tuning data of a plurality of channels and apply them to the tuner 4 in a cyclic manner. The broadcast signal is amplified by the intermediate frequency through the image IF unit 6, and the image signal is processed by the main image signal processing unit 12 and the sub image signal processing unit 14 through the switching switching of the mode switch unit 10 to the screen position. The screen playback position is designated by the designation unit 16, and the video output unit 18 reproduces the main / sub picture on the CRT screen.

In this state, the AGC unit 8 generates an AGC voltage for gain control of the image signal according to the plurality of channels from the image IF unit 6, and the synchronization separator 20 generates the main image signal processor. The synchronous signal is separated from the main video signal corresponding to the main screen processed by the video signal by (12), while the separated synchronous signal is counted by the synchronous counter 22 and generated as a counting output in the counting result. .

Accordingly, the microcomputer 28 generates an AGC voltage suitable for each broadcasting channel synchronously with the high speed channel switching state for the multiple channels of the tuner 4 based on the counting output from the synchronization counter 22. An adjustment control signal is generated so that the driving element 32 of the voltage adjusting unit 30 is induced at the collector end while the bias state is changed based on the voltage value of the adjustment control signal applied to the base end. The voltage value for the AGC voltage from the AGC unit 8 is varied so that it is supplied to the AGC input terminal of the tuner 4.

According to the present invention made as described above, in a multi-screen television capable of simultaneous reproduction of main and sub-screens, when a high-speed channel is tuned through a single tuner, AGC voltage generated for gain control of the broadcasting channel. It is possible to synchronously change the voltage value of each broadcasting channel to the channel switching state so that the gain control suitable for each broadcasting channel can be achieved, thereby making it possible to optimally perform a multi-channel broadcasting station for multi-screen playback. It has the advantage that it is.

Claims (2)

A tuner 4 for high-speed tuning of multiple channels according to the multi-screen playback function and an AGC voltage for gain control of the broadcast signal of multiple channels through the video IF unit 6 are generated and applied to the tuner 4. Main / sub image signal processing units 12 and 14 for processing the main / sub image signals according to the main / sub picture through the mode switch unit 10 according to the AGC unit 8 and the multi-screen reproduction function, respectively; In a multi-screen television having a screen position setting unit 16 for outputting a main / sub picture signal according to a main / sub picture to an image output unit 18, A sync counting unit 20 and 22 for counting sync signals separated from the main video signal according to the main screen; A tuning data memory 26 for storing tuning information for channel tuning for a plurality of broadcast channels; In accordance with the execution of the multi-screen playback function, the tuner 4 applies the tuning data for the high-speed tuning of a plurality of channels to the tuner 4 based on the tuning information of the tuning data memory 28. Microcomputer adjusting and controlling the voltage value of the AGC voltage from the AGC unit 8 to the respective broadcasting channels synchronously with the high-speed channel switching for the multiple channels of the tuner 4 based on the counting value of 28) and, And a voltage adjusting unit (30) which adjusts the voltage value of the AGC voltage from the AGC unit (8) for each broadcasting channel by adjustment control of the microcomputer (28). AGC voltage control device for multi-channel tuning. 2. The voltage regulating unit (30) according to claim 1, wherein the voltage adjusting unit (30) is constituted by a transistor (32) which is biased to adjust the voltage value with respect to the AGC voltage of the AGC unit (8) according to the adjustment control signal from the microcomputer (28). An AGC voltage regulating device for multi-channel tuning of a multi-screen television.