KR960006538B1 - Tuning stability apparatus for image appliance - Google Patents

Abstract

The device comprises a first switching unit for selectively transmitting at least more than one external image signal and a selected TV signal; an on screen display (OSD) area setting unit for generating vertical and horizontal blank signals by inputting a signal from the first switching unit; an external image/TV mode switch detecting unit for detecting a state switched an external image signal reception mode to a TV signal reception mode; a microcomputer for controlling the switching operation of the first switching unit according to the control command applied by a user and generating control signals for detecting the switched state from the external image/TV mode switch detecting unit; and a second switching unit for providing the horizontal blank signal from the OSD zone setting unit to an input terminal of the microcomputer under the control of the signal from the external image/TV mode switch detecting unit.

Description

Synchro Stabilizer in Imaging Equipment

1 is a system block diagram for explaining a reception mode switching control process conventionally performed for a television.

2 is a block diagram of a television equipped with a tuning stabilizer according to the present invention.

3 is an embodiment of the television / external image mode switching detection unit shown in FIG.

* Explanation of symbols for the main parts of the drawings

1: Detection part 2: 1st switching part

4: OSD setting unit 5: External image / TV mode switching detector

6: second switching unit 7: microcomputer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to tuning in a video apparatus, and more particularly, to a tuning stabilizer for ensuring stable tuning when switching from an external video mode to a television mode in a video apparatus capable of receiving a television signal. will be.

A video device capable of receiving a television signal (or broadcast signal) is commonly called a television receiver (or television). The video device is designed to receive a plurality of external video signals through external terminals in addition to the television signal. . FIG. 1 is a system block diagram for explaining a conventional reception mode switching control processing function for a television designed to receive a plurality of video signals as described above, and is a tuned broadcast output from the detector 1; FIG. This is an example configured to select and receive one of a composite video signal of a channel and first to third external video signals applied through an external terminal (not shown). Here, the first to third external video signals are in a signal-free state when the video signals provided from an external device such as a video device or a video camera or the corresponding external terminal are not connected to any kind of external device.

As shown in FIG. 1, the reception mode is controlled by the user's control command for the television capable of receiving the first to third external video signals and the television signal. That is, when the power is turned on, the reception mode of the television is controlled by the reception mode data set when the power is turned off in the microcomputer 7, but when the power is turned on, the reception mode change is required by the user's control command (for example, TV / When the video switching key is controlled) The microcomputer 7 outputs a reception mode switching control signal P such that the reception mode is changed. The received reception mode switching control signal P is transmitted to the first switching unit 2. The first switching unit 2 is a television signal composed of a composite video signal transmitted from the detector 1 by the reception mode switching control signal P transmitted from the microcomputer 7, and the first, second and third external video signals. Select one and send it. At this time, the selection processing is sequentially performed as in the "first external video signal-> second external video signal-> third external video signal-> telescopic vision signal-> first external video signal". The signal output from the first switching unit 2 is applied to the synchronization separating unit 3 and the OSD (On Screen Display) setting unit 4, respectively.

The synchronizing separator 3 separates the horizontal synchronizing signal from the video signal transmitted from the first switching unit 2 and transmits the horizontal synchronizing signal to the microcomputer 7, and the OSD region setting unit 4 from the first switching unit 2. In response to the transmitted video signal, horizontal and vertical blank signals HD and VD for setting an area for displaying caption information on the screen are transmitted to the microcomputer 7. Therefore, the microcomputer 7 controls the area in which the caption information is to be loaded using the horizontal and vertical blank signals HD and VD provided by the OSD region setting unit 4, and applies the horizontal synchronizing signal provided from the sync separating unit 3 to the microcomputer 7. Processing to display the video signal.

However, in the case where the reception mode is selected and processed as shown in FIG. 1, when the mode switching is performed from the third external video signal to the television signal, the synchronization separation unit 3 does not operate until the AFT (Automatic Fine Tuning) processing is completed. Since the horizontal synchronization signal could not be separated, a synchronization collapse phenomenon occurred on the displayed screen, and thus a normal image could not be displayed.

Accordingly, an object of the present invention has been devised in view of the above-described drawbacks, and it is an object of the present invention to provide a tuning stabilization device for stably tuning when switching from an external video signal to a television signal.

The apparatus according to the present invention comprises: a first switching unit for selectively transmitting at least one external video signal and a tuned television signal; An on-screen display (OSD) area setting unit which receives a signal output from the first switching unit 2 and outputs horizontal and vertical blank signals in order to set an area in which predetermined caption information is to be displayed; An external video / TV mode switching detection unit for detecting a state of switching from an external video signal reception mode to a television signal reception mode; A microcomputer outputting predetermined control signals P1 and P2 so as to detect switching operation of the first switching unit and a state switched by the external image / TV mode switching detection unit according to a control command applied by the user; And a second switching unit for switching the control by the signal output from the external image / TV mode switching detection unit to provide the horizontal blank signal output from the OSD region setting unit to the horizontal synchronous signal input terminal of the microcomputer.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is an internal block of a television having a tuning stabilizer according to the present invention, which controls the overall function of the television and outputs a signal indicating a reception mode control and reception mode switching time according to a command applied by a user. (7), the detection unit (1) and the microcomputer (7) that detects and outputs a composite video signal from the tuned broadcast signal and provides an intermediate frequency (IF, Intermediate Frequency) of the video signal detected by the microcomputer (7) One of a composite video signal controlled by the reception mode switching control signal P provided for mode switching and transmitted from the detector 1 and first, second and third external video signals transmitted through an external terminal not shown is A first switching unit 2 for switching to be transmitted, a synchronous separator 3 for separating the horizontal synchronization signal from the signal transmitted from the first switching unit 2, and outputting it to the microcomputer 7, and a first switching unit 2 ) OSD area setting unit 4 for outputting horizontal and vertical blank signals to the microcomputer 7 to set the area where the OSD information is displayed by receiving the signal transmitted from the microcomputer 7 and outputting the microcomputer 7 according to a user's mode switching command. In response to the signals output from the external video / TV mode switch detection unit 5 and the external video / TV mode switch detection unit 5 for detecting the time when the mode is switched from the external video signal to the television signal by the control signals P1 and P2. And a second switching unit 6 for controlling the horizontal blank signal output from the OSD region setting unit 4 as a horizontal synchronous signal Hsync to the microcomputer 7.

3 is an embodiment of the external image / TV mode switch detection unit 5 shown in FIG.

The television equipped with the tuning stabilizer according to the present invention configured as described above operates as follows to stabilize the tuning when switching from the third external video signal mode to the television mode. Prior to the description, the operation descriptions of the detector 1, the first switching unit 2, the synchronization separation unit 3, and the OSD region setting unit 4 are the same as those in FIG. Omit.

First, if a user command is not applied through a key input means (not shown) such as a remote controller at power-on, the microcomputer 7 controls the reception mode of the television such that the reception mode set at the time of power-off as usual is maintained.

However, when the reception mode switching control command is applied through the above-described key input means (not shown) while the power is turned on, the microcomputer 7 may switch the first mode switching unit 2 so that the reception mode switching control signal P may be switched. ) And P1 and P2 signals according to the currently switched mode. At this time, the output P1, P2 signal has the characteristics as shown in Table 1 below.

[Table 1] Output characteristics of P1 and P2

In more detail with reference to [Table 1], when the reception mode of the television is switched from the TV signal reception mode to the first external video signal reception mode by the user command, P1 and P2 output from the microcomputer 7 are all ' H 'is outputted in a logic state, and P1 and P2 are outputted in the' H, L 'state when switching from the first sub picture signal reception mode to the second external picture signal reception mode. At this time, the P1 and P2 signals output from the microcomputer 7 are provided for a predetermined time when the reception mode is switched, which is until the end of the AFT for the received TV signal when the third external video signal is switched to the TV signal mode. It is time considering the time. The P1 and P2 signals generated as described above are transmitted to the external image / television mode switching detector 5.

As shown in FIG. 3, the external image / TV mode switching detector 5 includes two transistors Q1 and Q2, resistors R1 and R2 connected to the base input terminals of the transistors Q1 and Q2, respectively, and a supply power source. Consisting of resistors R3 and R4 connected in series between (B +) and the electromotive power supply, one side of the (8) contact between the resistors R3 and R4 is connected to the collector terminals of the two transistors Q1 and Q2, (8) The other side of the contact is configured to be connected to the switching control signal input terminal of the second switching unit 6 to detect the time of switching from the third external video signal mode to the television signal mode.

In more detail, the P1 signal output from the microcomputer 7 is applied to the base terminal of the transistor Q1, and the P2 signal is applied to the base terminal of the transistor Q2. Transistors Q1 and Q2 are turned on / off by signals P1 and P2 applied to the base end. When the transistors Q1 and Q2 are npn type, the signals P1 and P2 applied to the base end are 'L'. It is off, and when it is 'H', it is on. Therefore, when P1 and P2 are both 'L' according to the conditions of the above [Table 1], the supply power B + is distributed by the resistors R3 and R4 so that the switching control signal input terminal of the second switching unit 6 is provided. Transmits the 'H' signal, and if any one of the signals P1 and P2 is in the 'H' state, the (8) contact point is connected to the ground power supply (GND) and the switching control signal input terminal of the second switching unit 6 Transmit the L 'signal.

The second switching unit 6 is switched by the switching control signal provided from the external image / TV mode switching detection unit 5 to output the horizontal blank signal HD transmitted from the OSD region setting unit 4 of the microcomputer 7. Transmit to horizontal sync signal input terminal (Hsync). That is, when the external image / TV mode switching detection unit 5 is operated as described above and the 'H' signal is output, the second switching unit ( 6) is turned on and transmits the horizontal blank signal HD output from the OSD region setting unit 4 to the horizontal synchronous signal input terminal Hsync of the microcomputer 7. However, when the signal output from the television / external image mode switching detection unit 5 is 'L', the second switching unit 6 is turned off because it is out of the state of switching from the third external image signal mode to the TV signal mode. In this state, the horizontal blank signal output from the OSD region setting unit 4 is not transmitted to the horizontal synchronous signal input terminal Hsync of the microcomputer 7. In this case, an element such as a relay may be used for the second switching unit 6.

As described above, the present invention stabilizes the synchronization by providing the horizontal blank signal output from the OSD region setting unit 4 as the horizontal synchronization signal during the AFT processing period when switching from the external video signal mode to the television signal mode. When the reception mode is switched, the AFT is not performed, thereby preventing the synchronization collapse from occurring on the displayed screen.

Claims (2)

A first switching unit 2 for selectively transmitting at least one external video signal and a tuned television signal; An on-screen display (OSD) area setting unit 4 which receives a signal output from the first switching unit 2 and outputs horizontal and vertical blank signals in order to set an area in which predetermined caption information is to be displayed; An external image / TV mode switching detection unit (5) for detecting a state of switching from the external image signal reception mode to the television signal reception mode; According to a control command applied by a user, a predetermined control signal P1, to control the switching operation of the first switching unit 2 and to detect the switched state in the external image / TV mode switch detection unit 5, may be used. A microcomputer 7 that outputs P2); And a switching control by a signal output from the external image / TV mode switching detection unit 5 to provide the horizontal blank signal output from the OSD region setting unit 4 to a horizontal synchronization signal input terminal of the microcomputer 7. And a second switching section (6). The second switching unit (2) according to claim 1, wherein the external image / TV mode switching detector (5) uses predetermined control signals (P1, P2) output from the microcomputer (7) as input signals. And a transistor (Q1, Q2) configured to output a signal for controlling the on-off state of the device.