JPH0541279U - PinP TV receiver - Google Patents

Abstract

(57) [Summary] [Purpose] Stable by discriminating the sync signals of parent and child image signals.
The TV screen is displayed, and when there is no video signal of the parent and child images, the output is muted to prevent the video noise output to the CRT. A first synchronization separation circuit for extracting a synchronization signal of a parent image signal, a first determination circuit for determining this synchronization signal, a second synchronization separation circuit for extracting a synchronization signal of a child image signal, and this synchronization A second discrimination circuit for discriminating a signal, a control circuit to which the output of the synchronization discrimination signal of the parent-child image and a switching signal for switching the video switching circuit are supplied, and a mute circuit for muting the output of the video switching circuit. It is provided and configured.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a PinP television receiver for displaying parent-child images, and more particularly to a PinP television receiver suitable for switching parent-child image signals.

[0002]

[Prior art]

 Conventionally, most of PinP television receivers for displaying parent-child images have been provided in the block diagram shown in FIG. In the figure, 1 is a parent image signal input terminal, 5 is a switching signal input terminal, 6 is a child image signal input terminal, and the parent image signals input to the input terminals 1 and 6 are the video switching circuit 9 This video switching circuit 9 is controlled by the switching signal input to the input terminal 5. Reference numeral 11 is a drive circuit for amplifying the parent-child image signal switched by the video switching circuit 9 and displaying a PinP-TV screen on the cathode ray tube 12.

The above-mentioned switching signal input to the input terminal 5 operates a mode switch (not shown) of the television receiver, and when the television receiver displays only the parent image, the video switching circuit 9 is connected to the a contact side. Control so that the parent image signal input to the input terminal 1 is output and supplied to the drive circuit 11, and when switching to child image display, the video switching circuit 9 is connected to the b contact side. Then, the child image signal can be output.

When the parent-child image is displayed on the CRT 12 as a PinP-TV screen at the same time, a switching signal synchronized with the vertical scanning signal and the horizontal scanning signal of the parent image signal of the television receiver is input to the input terminal 5. By this switching signal, the video switching circuit 9 can switch the contacts a and b to display the TV screen of the child image at a predetermined position on the TV screen of the parent image of the CRT 12.

[0005]

[Problems to be solved by the device]

 However, in the conventional PinP TV receiver described above, when the child image is displayed at a predetermined position of the parent image display, if the parent image signal disappears, the parent image synchronization signal disappears and the TV screen of the child image is disturbed. was there.

Further, since the television receiver is in the receiving state even if the parent image signal disappears, there is also a drawback that the TV screen becomes a noise screen when the synchronization is detuned.

The present invention has been made in view of the above points, and an object thereof is to solve the drawbacks of the conventional example, to discriminate the sync signal of the parent-child image signal, and automatically switch the video switching circuit. The purpose is to provide a PinP television receiver that controls and mutes the output signal when there is no video signal and does not display the image noise screen on the cathode ray tube.

[0008]

[Means for Solving the Problems]

 The PinP television receiver of the present invention controls a video switching circuit for switching between a parent image signal and a child image signal of the television by a switching signal, and outputs the switched image signal to a CRT via a drive circuit. In the image receiver, a first sync separation circuit for extracting the sync signal of the parent image signal, a first judgment circuit for judging this sync signal, and a second sync separation circuit for extracting the sync signal of the child image signal A second discriminating circuit for discriminating the synchronizing signal, a control circuit for supplying the synchronizing discriminating signal of the parent image, the synchronizing discriminating signal of the child image and a switching signal for switching the video switching circuit. , A mute circuit for muting the output of the video switching circuit, the output of the control circuit controls the video switching circuit to display a parent-child image, and the output of the control circuit controls the muting. Those configured to mosquitoes Tsu preparative video noise when no signal of the parent-child image signal by controlling the bets circuit.

An SG switching circuit for switching between the output of the mute circuit and the output of the video signal generator is provided, and the video signal from the video signal generator is output to the cathode ray tube when there is no signal of the parent and child images. May be.

[0010]

[Action]

 According to this invention, the sync signal of the parent image signal of the television is taken out by the first sync separation circuit, and the presence or absence of this sync signal is judged by the first determination circuit, while the sync signal of the child image signal is detected. Is extracted by the second synchronization separation circuit, the presence or absence of this synchronization signal is determined by the second determination circuit, and the output of the synchronization determination signal of the parent image and the output of the synchronization determination signal of the child image are supplied to the control circuit. ..

Further, a switching signal that controls switching between the parent image signal and the child image signal in synchronization with the vertical and horizontal scanning signal synchronous signals of the television receiver is supplied to the control circuit. In this way, by the discrimination output signal and the switching signal supplied to the control circuit, the video switching circuit is switched and controlled, and the parent-child image signal input to the video switching circuit can be output.

That is, when there is a synchronization determination signal for both the parent-child image signal, the video switching circuit is switching-controlled by the above-mentioned switching signal, and the TV screen for the child image is displayed at a predetermined position on the TV screen for the parent image. PinP-TV screen can be displayed.

Further, when there is only the parent image signal, the control circuit switches the video switching circuit to the contact terminal side of the parent image signal in accordance with the synchronization determination signal of the parent image signal, and the TV screen of the parent image shows the parent image signal. It is displayed in a synchronized state by the synchronization signal. On the other hand, when there is only a child image signal and no parent image signal, the control circuit switches the image switching circuit to the contact terminal side of the child image signal by the synchronization determination signal of the child image signal, and the TV screen of the child image is the child image. The signal can be displayed in sync with the sync signal.

Further, when there is no parent-child image signal, the output of the synchronization determination signal of the control circuit becomes zero, the control circuit outputs the mute signal to the mute circuit, and the output of the video signal is muted by the mute circuit. The Braun tube does not display the image noise, and the Braun tube is controlled to display black.

In this way, by discriminating the sync signal of the parent-child image signal, it is possible to obtain a stable TV screen without disturbing the TV screen in any case of displaying the parent-child image. Output of image noise can be prevented.

As another embodiment, an SG switching circuit is provided at the output of the mute circuit, and the SG switching circuit is supplied with the output of the mute circuit and the output of the video signal generator to output no signal of the parent-child image signal. Sometimes the SG switching circuit is connected to the video signal generator side and the video signal from the video signal generator is output to the cathode ray tube.

Thus, when there is no video signal of the parent-child image, video noise can be cut and at the same time, a TV screen such as a color pattern from a video signal generator or a multicolored color bar can be displayed on the CRT.

[0018]

【Example】

 An embodiment of a PinP television receiver according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of a main part of a PinP television receiver showing an embodiment, and FIG. 2 is a block diagram showing another embodiment. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 1, reference numeral 2 is a first sync separation circuit for extracting the sync signal of the parent image signal supplied to the input terminal 1. The sync signal output of the first sync separation circuit 2 is the first discrimination signal. It is discriminated by the circuit 3 and supplied to the control circuit 4. Reference numeral 7 is a second sync separation circuit for extracting the sync signal of the child image signal supplied to the input terminal 6, and the output of the sync signal from the second sync separation circuit 7 is judged by the second judgment circuit 8. It is supplied to the control circuit 4. A mute circuit 10 controls the output signal of the video switching circuit 9 by the mute signal from the control circuit 4.

In the PinP television receiver thus configured, when the parent image signal and the child image signal are supplied to both the input terminals 1 and 6, the sync signals are respectively generated by the first and second sync separation circuits 2 and 7. Is output and the outputs of the first and second discriminating circuits 3 and 8 for discriminating the presence or absence of the synchronizing signal are set to the low level and supplied to the control circuit 4.

Since the synchronization determination signals of the parent-child image signals supplied to the control circuit 4 are both at the low level, the control circuit 4 outputs the switching signal supplied from the television receiver as it is, By this switching signal, the video switching circuit 9 to which the video signal of the parent-child image is supplied is switched and controlled, and the PinP-TV screen of the parent-child image can be displayed on the CRT 12.

When the output synchronization determination signal of the first determination circuit 3 for the parent image signal is at the low level and the output synchronization determination signal of the second determination circuit 8 for the child image signal is at the high level The control circuit 4 judges that there is no child image signal and controls the switching of the video switching circuit 9 to the a-contact side, so that the TV screen on the cathode ray tube 12 can be all displayed as a parent image.

When the output synchronization determination signal of the first determination circuit 3 for the parent image signal is at the high level and the output synchronization determination signal of the second determination circuit 8 for the child image signal is at the low level, The control circuit 4 judges that there is no parent image signal and controls the video switching circuit 9 to switch to the b contact side, so that the TV screen on the cathode ray tube 12 can be displayed as a child screen TV screen.

Further, when both the output synchronization determination signals of the first and second determination circuits 3 and 8 of the parent-child image signal are at the high level, the control circuit 4 determines that there is no parent-child image signal. A mute signal is output, and this mute signal is supplied to the mute circuit 10. For this reason, the mute circuit 10 operates to mute ON to set the output to zero, the TV screen on the cathode ray tube 12 is displayed as a black TV screen, and the video noise when there is no signal of the parent-child image signal is prevented from being output to the cathode ray tube 12. You can

In this way, the presence / absence of the sync signal of the parent-child image signal is determined, and the TV screen corresponding to the presence / absence of the parent-child image signal is automatically displayed on the Braun tube 12, and the video noise is muted when the video signal is not present. Can be operated.

FIG. 2 shows another embodiment. In the figure, 13 is an SG switching circuit connected to the output of the mute circuit 10. This SG switching circuit 13 outputs the output of the mute circuit 10 and The output of the video signal generator 14 is supplied and is switched and controlled by a control signal from the control circuit 4.

As for the control signal of the control circuit 4 for controlling the switching of the SG switching circuit 13, the output synchronization discrimination signals of the first and second discrimination circuits 3 and 8 of the parent-child image signal are both at the high level, and the parent-child When there is no image signal, the SG switching circuit 13 switches to the b contact side and outputs the video signal of the video signal generator 14.

That is, when there is no parent-child image signal and the mute circuit 10 is muting to cut image noise, the CRT 12 display displays the video signal from the video signal generator 14, for example, red or blue. Color pattern signals and color bar signals can be displayed.

As described above, the PinP television receiver takes out the sync signal of the parent-child image signal, and a stable TV screen can be obtained in any case by each synchronization, and the image noise when there is no signal is cut, and the TV screen is displayed. Black display or video signal display is possible.

[0030]

[Effect of the device]

 As described above, the PinP television receiver according to the present invention automatically displays the PinP-TV screen of the parent image and / or the child image or the independent TV screen display on the brown tube by automatically determining whether each is synchronized. Since it can be displayed, there is an effect that the PinP-TV screen or a single TV screen can be stably displayed and the display disorder can be prevented.

Further, when there is no video signal of the parent image or the child image, the mute circuit provided in the output circuit can be turned on, so that the video noise of the output is cut and the CRT display is displayed in black or the video is displayed. There is also an effect that it is possible to set the color pattern display from the signal generator.

Moreover, it has excellent features such as a simple structure and easy implementation because it can be constructed at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a PinP television receiver according to the present invention.

FIG. 2 is a block diagram showing another embodiment.

FIG. 3 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 Parent Image Signal Input Terminal 2 First Sync Separation Circuit 3 First Discrimination Circuit 4 Control Circuit 5 Switching Signal Input Terminal 6 Child Image Signal Input Terminal 7 Second Sync Separation Circuit 8 Second Discrimination Circuit 9 Video switching circuit 10 Mute circuit 11 Drive circuit 12 CRT 13 SG switching circuit 14 Video signal generator

Claims (2)

[Scope of utility model registration request] 1. A PinP television receiver for controlling a video switching circuit for switching between a parent image signal and a child image signal of a television by a switching signal and outputting the switched image signal to a cathode ray tube through a drive circuit. A first synchronization separation circuit for extracting the synchronization signal of the parent image signal, a first determination circuit for determining this synchronization signal, a second synchronization separation circuit for extracting the synchronization signal of the child image signal, and this synchronization signal A second discriminating circuit for discriminating, a control circuit supplied with the output of the sync discriminating signal of the parent image, the output of the discriminating discriminant signal of the child image, and a switching signal for switching the video switching circuit, and the video switching circuit. A mute circuit for muting the output is provided, the output of the control circuit controls the video switching circuit to display a parent-child image, and the output of the control circuit controls the mute circuit. A PinP television receiver characterized in that it is configured to cut video noise when there is no parent-child image signal. 2. An SG switching circuit for switching between the output of the mute circuit and the output of the video signal generator is provided, and the video signal from the video signal generator is output to a cathode ray tube when there is no signal of the parent and child images. The PinP television receiver according to claim 1.