JP2000270345A - Television receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically prevent the deviation of screen by controlling a switch such that a synchronizing signal or a composite video signal is not supplied to a digital comb-line filter in an external display mode but the signal is detoured directly to a synchronizing separator circuit. SOLUTION: An input terminal 100 includes a terminal 12 to receive a composite video signal of a television signal, a terminal 1 to receive a composite video signal or a synchronizing signal from an external device, input terminals 2a-2c to receive an RGB signal from the external device and an input terminal 3 to receive a high speed switch signal. An input detection circuit ANDs the high speed switch signal and a synchronizing signal from a synchronizing separator circuit and applies peak holding to the ANDed signal to obtain a control signal, which is used for switching control of a switch circuit 5. In the case of the external display mode, the switches SW1, SW2 are switched to connect each of terminals 2, 3. Thus, the composite video signal bypasses a digital comb-line filter and is fed to the synchronizing separator circuit and a video chroma processing circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a color television receiver capable of inputting a GB signal and a composite video signal and having a digital comb filter as a YC separating means. Automatically prevents a screen phase shift caused particularly when an external display mode is executed. The present invention relates to a television receiver capable of performing such operations.

[0002]

2. Description of the Related Art Conventionally, an AV-compatible color television receiver has been provided with various additional functions as the number of video sources increases. There are various types of this additional function. For example, in addition to displaying the original television image, a video signal taken from an external device can be displayed on the entire screen or super-integrated on the television image screen. Some are displayed in a pause format.

In such a color television receiver capable of displaying a video signal from an external device, when the external display mode is set, a synchronous signal is supplied from the external device in addition to the RGB signal. I have.

[0004] Such a color television receiver has an R signal for receiving RGB signals from an external device.
It is provided with an input terminal for GB and an input terminal for a synchronization signal. In particular, in the case of a receiver for Europe, various signals are generally taken in via a 21-pin terminal.

When an RGB signal is input from an external device, a synchronizing signal is also input through a synchronizing signal input terminal. The synchronizing signal may be in the form of a composite video signal (composite signal). In some cases, only the synchronization signal is input.

The color television receiver is provided with a YC separation circuit for separating a luminance signal (Y) and a chrominance signal (C) from a composite video signal. For example, a digital comb filter is generally used. Therefore, in the receiver,
The composite video signal is taken into the digital comb filter, and the luminance signal (Y) and the chrominance signal (C) obtained by the YC separation are supplied to a subsequent processing circuit (for example, a video chroma processing circuit). Like that.

In such a color television receiver, when an RGB signal is input from an external device and a composite video signal is input to a synchronization signal input terminal, the composite video signal is supplied to the digital comb filter as described above. The input signal is YC-separated, and a synchronizing signal is separated from a luminance signal (Y) obtained by the YC separation by a synchronizing signal separating circuit. That is, this is the case where the external display mode is executed.

However, at this time, the signal that has passed through the digital comb filter takes 1-2 μs due to the processing.
, And the separated synchronization signal lags behind the RGB signal.
There is a problem that the screen at the time of displaying B is shifted to the left.

The external display mode includes a mode in which an external signal is displayed on the entire screen as described above and a mode in which the external signal is displayed in a superimposed format on a television image screen like a text signal. In the mode in which an external signal is displayed, the problem of the screen shift is remarkable, and in order to solve the problem, the user needs to adjust the screen position, which is troublesome.

[0010]

As described above, in a conventional color television receiver, an RGB signal from an external device is input through an RGB input terminal, and a sync signal or a composite signal is input through a sync signal input terminal. Input video signal,
Since the signal path for output to the synchronization signal separation processing via the digital comb filter is formed, the signal passing through the digital comb filter will be delayed when trying to execute the external display mode. Then, there is a problem that a phase difference occurs between the synchronization signal obtained thereafter and the input RGB signal, and as a result, the screen when displaying external RGB is shifted to the left. In order to solve this, the user needs to adjust the screen position, which is troublesome. That is, there is a problem that the screen shift cannot be automatically prevented beforehand.

In view of the above, the present invention has been made in view of the above-mentioned problem. In the external display mode, a synchronization signal or a composite video signal is not supplied to a digital comb filter, but is bypassed directly to a synchronization signal separation circuit. It is an object of the present invention to provide a television receiver that can automatically prevent a screen shift by performing switch control.

[0012]

According to the present invention, there is provided a television receiver, comprising: a first television receiver obtained by receiving and processing a television signal;
And a second RGB signal from an external device. The television receiver is capable of selectively switching and displaying on a display means, wherein the first signal including a synchronization signal and the second signal are transmitted from the external device. An input terminal to which each of the second RGB signals is supplied, a receiving means for receiving a television signal and outputting a composite video signal, and a composite video signal from the receiving means being inputted to separate a luminance signal and a chrominance signal And a synchronizing separation circuit for selectively receiving a luminance signal from the YC separating circuit or the first signal from the input terminal and separating a synchronizing signal from the input signal A signal processing circuit that receives the luminance signal and the color signal from the YC separation circuit, generates and outputs the first RGB signal, and a first RGB signal from the signal processing circuit.
A signal and the second RGB signal from the input terminal, respectively, and a selection unit for selectively outputting one of the RGB signals, and an RGB signal selected and output by the selection unit are supplied. And display means for scanning based on a synchronization signal from the synchronization separation circuit. In a mode in which the second RGB signal is displayed on the entire surface of the display means, the first signal is displayed. The first RG is input to the synchronization separation circuit and is displayed on the display means.
In a mode in which a B signal is displayed, a luminance signal from the YC separation circuit is input to the synchronization separation circuit.

According to the present invention, in a mode in which an image based on an RGB signal from an external device is displayed on the entire screen, a synchronization signal or a composite video signal from the external device is applied to the Y signal.
A signal path is formed so as to bypass the C separation circuit and supply the signal to the synchronization separation circuit. Thereby, the phase delay of the synchronization signal, which has conventionally been caused by the passage through the YC separation circuit, can be prevented, and the phases of the synchronization signal and the RGB signal can be matched, so that the screen shift can be prevented.

[0014]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration example of a television receiver according to an embodiment of the present invention. In FIG. 1, components that are not directly related to the present invention are omitted for simplification of description.

As shown in FIG. 1, a television receiver according to the present embodiment has a receiving antenna 300a, a TV receiving circuit 300, an input terminal 100, a digital comb filter 4,
Switch circuits 5, 8, V / C / D circuit 6, input detection circuit 9, display means 10, deflection circuit 11, and AV switch 13
Etc.

An RF (high frequency) television signal received by the receiving antenna 1 is supplied to a TV receiving circuit 300. The TV receiving circuit 300 is a circuit that receives an RF television signal and generates a composite video signal, and includes a tuner, a video detection circuit, and the like. The composite video signal generated by the TV receiving circuit 300 is provided to the input terminal 100.

An input terminal 100 is a terminal 1 to which a synchronization signal or a composite video signal from the external device 200 is input, and
The terminals 2a, 2b and 2c to which the B signal is input, and the high-speed switch signal S which indicates "H" during the period when the RGB signal is input.
1 is input. Further, it has a terminal 12 to which a composite video signal from the TV receiving circuit 300 is input. Although the input terminal 100 is configured to have several other terminals,
It is omitted because it is not directly related to the present application.

The external device 200 is an electronic device such as a DVD or a personal computer.
Signal, sync signal or composite video signal, high-speed switch signal S
1 is supplied to each corresponding terminal of the input terminal 100.

The AV switch 13 is a switch circuit for selecting and outputting one of a plurality of video and audio signals. In the figure, the AV switch 13 receives a composite video signal from the TV receiving circuit 300 as a video input. (Television signal) and a signal (composite video signal or synchronization signal) from the external device 200 or the like are shown as switch circuits. Actually, other video input terminals are included, but are omitted because they are not directly related to the present application. It also has an audio signal selection function, but is omitted. The output of the AV switch 13 is connected to the digital comb filter 4 and the switch SW1 of the switch circuit 5,
The input is provided to each input terminal 2 of SW2.

Since the digital comb filter 4 is provided as a YC separation circuit as described above, the luminance signal (Y) and the chrominance signal (C) are obtained by subjecting the supplied composite video signal to YC separation processing. For the luminance signal (Y), the input terminal 1 of SW1 of the switch circuit 5 is provided, and for the chrominance signal (C), the input terminal 1 of SW2 of the switch circuit 5 is provided.
Respectively.

In this embodiment, switch circuits 5, 8 and an input detection circuit 9 are provided to solve the problems in the prior art. Explaining in order, the switch circuit 5 includes a signal that has passed through the digital comb filter 4,
Alternatively, a signal which does not pass (an output signal from the AV switch 13) is switched to the next stage V / C / D circuit 60 for output, and in the figure, for example, two switches SW1, S
W2. These switches SW1, S
W2 performs a switching operation in conjunction with it, and its switching is controlled based on a control signal a from the input detection circuit 9. The output signal from each output terminal 3 of these switches SW1 and SW2 is V /
It is supplied to the C / D circuit 60.

The V / C / D circuit 60 includes a video (Video),
It is an IC for color (Chroma) and deflection (Deflection) processing, and includes a video chroma processing circuit 6 and a sync separation circuit 7. The video / chroma processing circuit 6 uses the output signal (luminance signal (Y) signal) from the output terminal 3 of the SW1 and the output signal (color signal (C) signal) from the output terminal 3 of the SW2 as RGB. Generate a signal and generate R
The GB signal is output to each input terminal of the switch circuit 8. Note that RGB signals obtained by processing television signals are shown as r, g, and b signals.

An output signal (luminance signal) from the output terminal 3 of the switch SW1 is supplied to the sync separation circuit 7. The synchronization separation circuit 7 separates the synchronization signal from the input luminance signal and supplies the separated synchronization signal to the deflection circuit 11.

The switch circuit 8 includes an r, g, b signal obtained by processing the television signal and an R signal from the external device 200.
It receives a GB signal and selectively outputs one of them. In the figure, the switch is composed of three switches SW1, SW2 and SW3. These three switches SW1 to SW3
, Input from the video chroma circuit 6
g and b signals are supplied, while each input terminal 2 is supplied with RGB signals from the external device 200, and a signal selected via each output terminal 3 of each of the switches SW1 to SW3. Is output to the display device 10. These switches SW1 to SW3 perform a switching operation in conjunction with each other, and their switching is controlled based on a high-speed switch signal S1 supplied from the input terminal 3 of the input terminal 100. .

For example, when the high-speed switch signal S1 is in the "H" period, the switches SW1 to SW3 connect between the terminals 2-3 as shown by the dashed lines in FIG.
RGB signals from 0 are selectively output. Conversely, during the period when the high-speed switch signal S1 is "L" (that is, when the external RGB
In the case where there is no signal), the switches SW1 to SW3
Operates to connect the terminals 1-3 and to selectively output the r, g, and b signals based on the television signal.

The display device 10 is a display device for a color display, for example, a CRT or the like. When the selection output signal of the switch circuit 8 is supplied, the display device 10 displays an image based on the supplied RGB image signal. At this time, the deflection circuit 6 deflects the electron beam of the RGB video signal supplied to the display device 10 optimally in the horizontal and vertical directions at a frequency based on the supplied horizontal and vertical synchronization signals. Perform control.

In this embodiment, an input detection circuit 9 for detecting that an RGB signal is supplied from the external device 200 is provided. The input detection circuit 9 is supplied with the synchronization signal from the synchronization division circuit 7 and the high-speed switch signal S1 supplied from the input terminal 3 of the input terminal 100.

For example, the input / output detection circuit 9 ANDs the synchronization signal from the synchronization separation circuit 7 with the high-speed switch signal S1, and peak-holds the AND output. A control signal a is generated based on the result of the peak hold, and the control signal a is supplied to the switch circuit 5 to control the switching of the switch circuit 5.

When the RGB signals from the external device 200 are displayed on the entire screen, the high-speed switch signal S1 is at "H" level over the entire period, and this is ANDed with the synchronization pulse (synchronization signal). A pulse is output during a period coincident with the synchronization pulse, and a peak is held, whereby a control signal a of "H" is always obtained, and the connection between the 2-3 terminals of the switches SW1 and SW2 of the switch circuit 5 is established. can do. That is, the signal bypassing the digital comb filter 4 is supplied to the V / C / D circuit 60. For this reason, since the signal does not pass through the digital comb filter 4, the output of the sync separation circuit 7 is
The phase matches the RGB signal supplied from 0, so that no phase shift occurs on the screen.

The external device 20 is included in the television signal.
When superimposing the RGB signals from 0, the high-speed switch signal S1 is “LOW” for most of the period, and is “H” only during the period when the RGB signals are input. Therefore, the input detection circuit 9 takes the synchronization pulse and the AND,
Even if the peak is held, the output control signal a is “LOW”.
Thus, the switches SW1 and SW2 of the switch circuit 5 are coupled between the 1-3 terminals. Therefore, the television signal passes through the digital comb filter 4 and
After the C separation, it is supplied to the V / C / D circuit 60.

When there is no RGB signal from the external device 200 and only the television signal is supplied to the entire screen, the high-speed switch signal S1 becomes "LOW" for the entire period. Even if AND is taken, the output control signal a is always "LOW", and the switches 1-3 of the switches SW1 and SW2 of the switch circuit 5 are connected.

When the television signal is monochrome or the like (when the YV separation circuit is unnecessary), this is detected by the video / chroma processing circuit 6, and the control signal b is indicated by the dashed line in the figure based on the detection result. May be generated, and switch switching control may be performed based on the control signal b so that the terminals 1-3 of the switches SW1 and SW2 of the switch circuit 5 are connected.

According to the above configuration, the input detection circuit 9 and the switch circuits 5 and 8 do not supply the synchronizing signal or the composite video signal to the digital comb filter 4 in the external display mode, but directly supply the synchronizing signal to the synchronizing signal separating circuit 7. Since the switch switching control can be automatically performed so as to form a bypass signal path, the phase of the output of the synchronization separation circuit 7 and the RGB signal supplied from the external device 200 can be matched, and the It is possible to prevent a phase shift.

Next, an operation which is a feature of this embodiment will be described.

Now, it is assumed that an RGB signal is supplied from the external device 200, and an external display mode for displaying an image based on the RGB signal on the entire screen is executed.

Then, the input detection circuit 9 makes use of the fact that the input high-speed switch signal S1 is "H" for the entire period, ANDs this pulse with the synchronization pulse (synchronization signal), and matches it with the synchronization pulse. Pulse is output during the
By peak-holding this, a control signal a of "H" is always obtained, and the switch 5 is controlled to be switched based on the control signal a. At the same time, since the high-speed switch signal S1 is "H", each of the switches SW1 to SW3 of the switch circuit 8 connects between the terminals 2-3 and selectively outputs the RGB signal from the external device 200.

Then, each switch SW of the switch circuit 5
The switching operation of SW1 and SW2 is controlled based on a control signal a so as to couple between terminals 2-3. As a result, the signal bypassing the digital comb filter 4 becomes V /
Since the signal is supplied to the C / D circuit 60, the processing by the digital comb filter 4 is avoided.
The phase with the GB signal matches, and the external device 20
The screen based on the RGB signals from 0 is displayed optimally without phase shift. Therefore, there is no need for the user to adjust the screen position.

Next, the external device 20 is included in the television signal.
It is assumed that an external display mode for superimposing RGB signals from 0 has been executed.

Then, the high-speed switch signal S1 supplied to the input detection circuit 9 becomes "LOW" for most of the period,
Since it becomes “H” only during the period when the RGB signal is input, the output control signal “a” becomes “LOW” even when the input detection circuit 9 takes the synchronizing pulse and AND and holds the peak.

Therefore, each switch S of the switch circuit 5
W1 and SW2 are switched and controlled so as to be connected between the 1-3 terminals. Therefore, the television signal is
After VC separation through the comb filter 4, V / C / D
The switch 8 is supplied to the circuit 60 and is supplied as r, g, b signals.
Are output to the respective input terminals 1 of the switches SW1 to SW3.

At this time, based on the high-speed switch signal S1, the switch 8 switches the signals of the switches SW1 to SW3 to 1-.
Since the switching operation is controlled at a high speed so as to alternately connect the three terminals and the two or three terminals, the display of the display device 10 includes a part of the television image screen,
A video screen based on the GB signal is superimposed and displayed.

It is also assumed that there is no RGB signal from the external device 200 and a normal display mode for displaying only a television signal on the entire screen is executed. Then, the high-speed switch signal S1 becomes “LOW” during the entire period, and the input / output detection circuit 9
, The output control signal a is always "LOW" even if the sync pulse is ANDed. That is, the input detection circuit 9 detects that the RGB signal from the external device 200 is not supplied, and based on the control signal a which is always “LOW”,
1 for each of the switches SW1 and SW2 of the switch circuit 5
The switch is controlled so that the -3 terminals are connected. Therefore, the television signal is transmitted to the digital comb filter 4.
And then supplied to the V / C / D circuit 60 as r, g, b signals.
It is output to each input terminal 1 of SW1 to SW3.

Thereafter, the switch circuit 8 outputs "LOW"
Based on the high-speed switch signal S1, the switching operation is controlled so that these switches SW1 to SW3 are connected between the terminals 1-3, so that only the television image screen is displayed on the screen of the display device 10. Will be done.

Therefore, according to the present embodiment, in a television receiver including a digital comb filter, an input terminal capable of inputting an RGB signal, a composite video signal, or a synchronization signal from an external device, a switch is provided. By providing the switch switching control units such as the circuits 5, 8 and the input detection circuit 9, the synchronization signal or the composite video signal is not supplied to the digital comb filter in the external display mode, but is directly bypassed to the synchronization signal separation circuit. Switch can be controlled in this way, preventing phase shift with the synchronization signal beforehand,
Screen shift can be prevented.

In this embodiment, the input device 9 uses the high-speed switch signal S1 to output the external device 2
It has been described that the input of the RGB signal from 00 is detected, and based on the detection result, processing such as AND and peak hold is performed to generate the control signal a and control the switching of the switch circuit 5. The function of 9 itself may be provided in a control microcomputer that controls the entire system of the television receiver, and may be configured integrally. Thus, the number of parts can be reduced. Of course, the switching control is performed in conjunction with the control of the entire system, but the same effect is obtained.

[0046]

As described above, according to the present invention, the switch control is performed such that the synchronization signal or the composite video signal is not supplied to the digital comb filter in the external display mode but is bypassed directly to the synchronization signal separation circuit. By having a configuration that
It is possible to provide a high-definition television receiver that can automatically prevent screen displacement.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a television receiver of the present invention.

[Explanation of symbols]

 1-3: terminals, 4: digital comb filter (YC separation circuit), 5, 8: switch circuit, 6: video chroma processing circuit, 7: synchronization separation circuit, 9: input detection circuit, 10: display device ( CRT), 11: deflection circuit, 13: AV switch, 100: input terminal, 200: external device, 300: TV receiving circuit, 300a: receiving antenna.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference)

Claims (3)

[Claims] 1. A television receiver capable of selectively switching between a first RGB signal obtained by receiving processing of a television signal and a second RGB signal from an external device and displaying on a display means. An input terminal to which a first signal including a synchronization signal and the second RGB signal are respectively supplied from the external device; a receiving means for receiving a television signal and outputting a composite video signal; A YC separation circuit that receives a composite video signal from the means and separates and outputs a luminance signal and a chrominance signal; and selectively outputs the luminance signal from the YC separation circuit or the first signal from the input terminal. A synchronization separation circuit for separating a synchronization signal from the input signal; a signal processing circuit for receiving a luminance signal and a color signal from the YC separation circuit and generating and outputting the first RGB signal A selection unit that receives a first RGB signal from the signal processing circuit and the second RGB signal from the input terminal, and selectively outputs any one of the RGB signals; And display means for scanning based on the synchronization signal from the synchronization separation circuit, and displaying the second RGB signal on the entire surface of the display means. In the mode, the first signal is input to the synchronization separation circuit, and in the mode in which the first RGB signal is displayed on the display means, the luminance signal from the YC separation circuit is subjected to the synchronization separation. A television receiver characterized in that input is made to a circuit. 2. A television receiver capable of selectively switching between a first RGB signal obtained by receiving and processing a television signal and a second RGB signal from an external device to display on a display means. Receiving means for receiving a television signal and outputting a composite video signal; a first terminal to which a synchronization signal or a composite video signal is supplied from the external device; and a second terminal for receiving the second RGB signal from the external device.
An input terminal having a plurality of terminals to which a signal and a switching signal representing a display period of the second RGB signal are respectively supplied; a composite video signal from the receiving means; and a signal from the first terminal, respectively. A first selection unit that receives and selects one of them, and outputs a selected signal; a YC separation circuit coupled to an output terminal of the first selection unit to separate a luminance signal and a chrominance signal from a composite video signal; A luminance signal from the YC separation circuit and a signal from an output terminal of the first selection unit are input, respectively, a second selection unit for selecting and outputting one of them, and a selection output by the second selection unit. A synchronization separation circuit for separating a synchronization signal from the received signal, a signal processing circuit for generating and outputting the first RGB signal based on a luminance signal and a chrominance signal from the YC separation circuit. A first RGB signal from the signal processing circuit, the said second RGB signal from the input terminal is inputted, one of R in response to the switching signal
Third selection means for selectively outputting a GB signal; display means for receiving the RGB signal selected and output by the third selection means and scanning based on a synchronization signal from the synchronization separation circuit; And a detection means for generating a predetermined detection signal in a mode in which the second RGB signal is displayed on the entire surface of the display means, wherein the second selection means is responsive to the detection signal. Control and
In the mode, a signal supplied to the first terminal is supplied to the synchronization separation circuit without passing through the YC separation circuit. 3. The detection means comprises: a logical product circuit for obtaining a logical product of an output from the synchronization separating circuit and the switching signal; and a peak hold circuit for holding an output of the logical product circuit for a predetermined period. The television receiver according to claim 2, wherein: