JPH0447779A - Television signal channel selection - Google Patents

Abstract

PURPOSE:To prevent a vertical synchronizing signal disturbance caused at channel changeover from being displayed on an external display device by muting only a video signal of a composite video signal obtained as a channel selection output signal resulting from selecting a channel of a television signal over a prescribed period. CONSTITUTION:A channel selection device is provided with a control means 9, which controls a video signal of a composite video signal obtained as a channel selection output signal by a channel selection means 2 at channel selection control to be muted over a prescribed period. A picture mute signal is applied for a sufficient prescribed time such as several tens mm to several hundreds mmsec to allow a monitor device to lock a vertical synchronizing signal pulse of a new channel. Thus, a television signal of a desired channel is selected without causing disturbance due to the vertical synchronizing signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a television signal tuning device for receiving television signals.

[Summary of the invention] The present invention mutes only the video signal for a predetermined period of time on a composite video signal, which is a horn signal from which a television signal is tuned. This is a television signal selection device that can switch between channels.

Further, the present invention provides a system for adjusting the phase of a synchronizing signal of a composite video signal, which is a tuning output signal obtained by tuning a television signal, to match the phase of a synchronizing signal of an internal signal of a composite video signal having a constant video level. This television signal selection device outputs an internal signal with a constant video level while performing pull-in control, thereby making it possible to switch channels without any noticeable flow.

[Conventional technology]

In general, a television receiver includes a so-called television tuner, that is, a tuning section that selects the television signal of a desired channel, and an image of the television signal of the channel selected by the tuning section that is displayed on the display screen. and a display section, which are arranged in a common housing.

The display section in the television receiver displays an image in synchronization with a synchronization signal superimposed on a composite video signal obtained as a channel selection output signal from the channel selection section.

Normally, in a television receiver, when the selected channel is switched, the image displayed on the display screen of the display unit is displayed until the image is synchronized with the synchronization signal of the new channel.
It is known to produce a so-called V (vertical synchronization signal) flow.

This V flow is, for example, from channel A shown in FIG. 5(a) to channel B shown in FIG. 5(d).
If you change the channel in
- As shown in FIG. 2(d), the image is displayed in a state where the image flows vertically on the screen.

This means that the channel A vertical synchronizing signal (■ pulse) shown in FIG. 6(a) and the channel B vertical synchronizing signal shown in FIG. 6(b) are, for example, 1. -1. This is caused by the temporal shift and phase difference. However, if such a flow is seen when switching channels, it is unnatural and very difficult to see.

Therefore, some of the above-mentioned television receivers, for example,
When switching from channel A shown in Figure (a) to channel B shown in Figure (C), in order to prevent the viewer from seeing the above V flow, the internal synchronization signal is set to the channel that was switched at the time of channel switching. ■The video signal is muted as shown in (b) of the same figure until it is drawn into the pulse, and then displayed on the display screen as shown in (c) of the same figure after it is completely drawn into the V pulse. It is something.

In addition, conventional television receivers, television tuners,
That is, monitor devices that do not have a built-in channel selection section are known, and television signal channel selection devices that are used in combination with these devices are known.

[Problem to be solved by the invention]

However, in a television receiver equipped with the above-mentioned channel selection section, since the television receiver itself can recognize the channel selection operation, a function such as blanking is provided in advance to prevent the above-mentioned V flow from occurring. Although it is possible to
When displaying an image based on the television signal of a channel selected by the externally connected television signal channel selection device on the display screen of the television signal receiver, monitor device, etc., the monitor device, etc. Since it is not possible to recognize the channel selection operation of the television signal channel selection device, it has not been possible to apply the above-mentioned blanking to prevent the channel from appearing.

This V flow is very difficult to see and does not give a good image to the user, such as degrading the image of the device itself.

Therefore, the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a television signal selection device capable of selecting a desired channel of a television signal without showing any flow. purpose.

[Means for Solving the Problems] A television signal tuning device according to the present invention includes a tuning means for tuning a television signal, and a muting means for muting a tuning output signal from the tuning means. and controlling the tuning operation of the tuning means, and muting only the video signal for a predetermined period on the composite video signal obtained as the tuning output signal from the tuning means during the tuning control operation. The above-mentioned problem is solved by having a control means for controlling the muting means.

Further, the television signal tuning device according to the present invention includes a tuning means for tuning a television signal, an internal signal generation means for generating a composite video signal having a constant video level as an internal signal, and a channel selection means for tuning a television signal; switching means for switching and outputting a tuning output signal from the channel selection output signal and an internal signal from the internal signal generation means; Control is performed to pull in the phase of the synchronization signal of the internal signal generated by the internal signal generating means into the phase of the synchronization signal of the composite video signal obtained as the output signal, and during this pull-in control operation, the internal signal is selected. The above-mentioned problem is solved by having a control means for controlling the switching control means.

[Effect]

The television signal channel selection device according to the present invention mutes only the video signal of the composite video signal of the selected channel over a predetermined period during a channel selection control operation.

Further, the television signal selection device according to the present invention performs pull-in control of the internal signal generation means during the channel selection braking operation,
During this pull-in control operation, the internal signal generating means outputs a composite video signal with a constant video level as an internal signal, and then outputs the composite video signal of the selected channel.

[Embodiments] Hereinafter, embodiments of the television signal channel selection device according to the present invention will be described with reference to the drawings.

A television signal selection device according to a first embodiment of the present invention includes a tuner section 2 to which a television signal received by an antenna 1 is supplied, as shown in FIG.

Tuning operation of the tuner section 2 is controlled by a control section 9 using a microcomputer (CPU).

That is, for example, remote controller (remote control) 1
A signal specifying a desired channel from the receiver 3 or the like is supplied to the controller 9 via the receiver 12. This control section 9
supplies a control signal to the tuner section 2 to select a designated channel. The television signal of the channel specified by the control signal from the control section 9 is selected in the tuner section 2.

The composite video signal of the designated channel obtained as the tuning output signal from the tuner section 2, that is, the signal in which the vertical synchronization signal (V pulse) and the horizontal synchronization signal (H pulse) are superimposed on the video signal, is sent to the selector 3. Supplied.

In addition to the composite video signal, the selector 3 is supplied with, for example, a video signal from a video tape recorder via an input terminal 4 and a reproduction signal from an optical disk reproduction device via an input terminal 5.

The selector 3 is controlled by a control signal from the control section 9 and selects one of the signals.

In this case, a composite video signal, which is the second channel selection output signal, is selected, and the composite video signal is supplied to the synchronization signal separation circuit 6 and the muting circuit 10.

The synchronization signal separation circuit 6 receives the supplied tuning output signal,
That is, an H pulse and a V pulse are separated from the composite video signal and outputted through output terminals 7 and 8, respectively.

Here, if you switch from the currently selected channel to another channel, the phase of the V pulse of the current channel and the phase of the V pulse of the switched channel do not match, so the television On the side of the monitor device externally connected to the signal channel selection device, a so-called V flow occurs until the phase of the (1) pulse of the composite video signal of the switched channel is drawn in.

Therefore, when the control section 9 detects this channel switching, it supplies an image muting signal to the muting circuit 10.

The muting circuit 10 normally operates, for example, at the second
The supplied composite video signal as shown in FIG. By doing so, a video signal having a constant video level and a synchronization signal superimposed thereon as shown in FIG. 2(b) is outputted via the output terminal 11. Since the video signal outputted after such image muting is set to the lowest level, that is, a constant black level, a black screen is displayed on the monitor device side. Note that the level of the video signal when the image is muted does not have to be the above-mentioned black level as long as it is constant. In addition, this image mute signal has a predetermined time that is sufficient to draw in the pulse of a new channel on the monitor device side, for example, several tens of millimeters to several hundred millimeters.
It is set to be supplied only to 5ec. When the supply of this picture mute signal is turned off, the monitor device draws in the pulse of the new channel, and the television signal selection device receives the switched new channel pulse as shown in Figure 2 (C). In order to supply the composite video signal of the channel from the output terminal 11 to the monitor device side, the V
Channel switching can be completed without showing the flow to the viewer.

As described above, as in the first embodiment of the television signal channel selection device according to the present invention, when switching channels, the process continues for a predetermined period until the pull-in of pulses of the composite video signal of a new channel is completed on the monitor device side. Then, a composite video signal with only the video signal at a constant level is supplied to the monitor device using both mute signals, and after the monitor device finishes pulling in the pulses of the composite video signal of the new channel, the new channel is By supplying the composite video signal of the channel to the monitor device side, it is possible to prevent the above-mentioned V flow from being shown to the viewer.

Next, a second embodiment of the television signal channel selection device according to the present invention will be explained.

In this second embodiment, the same components as those of the television signal channel selection device of the above-described first embodiment are given the same reference numerals, and detailed explanation thereof will be omitted.

The television signal selection device according to the second embodiment is as follows:
Similar to the television signal selection device according to the first embodiment described above, the device includes a tuner section 2 to which the television signal received by the antenna 1 is supplied.

A composite video signal of the selected channel obtained as a channel selection output signal from the tuner unit 2 is supplied to the synchronizing signal separation circuit 6 and one terminal 14a of the selector 14 via the selector 3.

The synchronization signal separation circuit 6 separates the H pulse and the V pulse from the tuned composite video signal obtained as the tuned output signal from the tuner section 2.

Then, the H pulse is outputted via the output terminal 7, and the ■ pulse is outputted via the output terminal 8 and is supplied to the control section 9.

When the control section 9 detects channel switching by a signal from the remote controller 13 or the like, it supplies a reset pulse to the internal signal generation circuit 15 and a selection signal to the selector 14 .

When the internal signal generating circuit 15 is supplied with the reset pulse, it is of the same standard (for example, NTSC system) as the composite video signal obtained as the tuning output signal of the tuner section 2, and only outputs the video signal at a certain level ( An internal signal, which is a composite video signal with a black level, for example, is supplied to the terminal 14b of the selector 14, and a V pulse of this internal signal is supplied to the control section 9.

When the selector 14 receives a selection signal from the control section 9, it switches the selection terminal to the terminal 14b.

As a result, the internal signal is outputted via the output terminal 11.

As described above, this internal signal is, for example, No. 13 with a constant black level, so that a black screen is displayed on the monitor device externally connected to the output terminal 11.

Note that the level of this internal signal may be arbitrary, such as a black level or a white level, as long as it is constant.

On the other hand, the control section 9 gradually adjusts the phase of the pulse of the channel selection output signal supplied from the tuner section 2, the composite video signal of the selected channel, and the phase of the pulse of the internal signal. The above internal signal generation circuit 1
Control 5.

That is, the signal shown in FIG. 4(a) is transmitted to the tuner section 2.
Assuming that the pulse of the tuning output signal is
learns the phase of the pulse (1) of the channel selection output signal and supplies the reset pulse to the internal signal generation circuit 15. The internal signal generating circuit 15 supplies an internal signal V pulse to the control section 9 when the reset pulse is supplied. The control unit 9 compares the phase of the V pulse of the internal signal obtained each time the reset pulse is sent with the phase of the V pulse of the channel selection output signal described in 1. Send the above reset pulse. The control unit 9 repeats such operations, for example, from FIG. 4(b) to FIG.
As shown in e), the phase of the ■ pulse of the internal signal and the phase of the ■ pulse of the channel selection output signal are gradually matched. - The pull-in time of the V pulse of the tuning output signal by the tuner section 2 is controlled so as to be the same as the pull-in time of the V pulse sent to the monitor device, for example. Then, at time t4, when the phase of the ■pulse of the channel selection output signal shown in FIG. 4(a) matches the phase of the ■pulse of the internal signal shown in FIG. The signal is supplied to the selector 14 mentioned above.

In response to this selection signal, the selector 14 switches the selection terminal to the terminal 14a. As a result, the channel selection output signal of the switched channel is outputted via the output terminal 11. That is, the second control section 9 controls the second selector 14 to select the internal signal until the phase of the V pulse of the channel selection output signal matches the phase of the V pulse of the internal signal.

On the monitor device side externally connected to the output terminal 11,
By performing the pulse pull-in for the above internal signal, the image display state based on the composite video signal of the new channel switched by this television signal channel selection device without displaying the flow on the display screen. can move to.

Note that some monitor devices are slow in pulling in pulses. For this reason, a muting circuit 10 is provided between the selector 14 and the output terminal 11, and the muting circuit 10 mutes and outputs only the video signal for a predetermined period during the channel selection control operation. You may also do so.

In this case as well, similarly to the first embodiment, the muting time is set to be a time sufficient for the monitor device to draw in pulses, for example, several tens of millimeters to several hundred millimeters.
It is preferable to set it to 5ec. By applying this muting, it is possible to prevent the above-mentioned (1) pulse from being drawn in slowly by a monitor device from showing the flow (2) to the viewer.

As described above, as in the second embodiment of the television signal selection device according to the present invention, when a channel change is detected, the output signal from the internal signal generation circuit 915 is generated instead of the selection output signal of the switched channel. An internal signal is supplied to the monitor device side, and control is performed to gradually match the phase of the pulse of this internal signal with the phase of the pulse of the tuning output signal, and the phase of the V pulse of the internal signal and the tuning output signal are controlled. By supplying the channel selection output signal of the switched channel to the monitor device when the phase of
Since the channel selection output signal with synchronized pulses can be supplied to the monitor device side, it is possible to prevent the viewer from seeing the flow. In addition, by applying muting for a predetermined time to the tuning output signal that is supplied when the phase of the V pulse of the internal signal and the phase of the tuning output signal (■ pulse) match, the pulse is pulled in. Even on monitors that are slow, muting is applied for a sufficient period of time to draw in the V pulse, so that the viewer will not be able to see the flow.

In the above-described embodiment, the muting time is several tens of millimeters to several hundreds of millimeters, 5 ec, but it may be any number of seconds and is not limited to this numerical value.

〔Effect of the invention〕

The television channel selection device according to the present invention mutes only the video signal for a predetermined period of time on a composite video signal obtained as a channel selection output signal obtained by selecting a television signal, thereby suppressing the flow that occurs when switching channels. can be prevented from being displayed on an external display device.

Further, the television signal tuning device according to the present invention synchronizes the phase of the synchronization signal of the composite video signal, which is the tuning output signal obtained by tuning the television signal, and the composite video signal, which has a constant video level, with the internal signal. By outputting an internal signal with a constant video level while controlling the input to match the phase of the signal, it is possible to prevent the flow that occurs when switching channels from being displayed on an external display device. .

Therefore, according to the present invention, it is possible to provide a television signal selection device that can select a desired channel of television signal without showing any flow.

[Brief explanation of drawings]

FIG. 1 shows a first part of a television signal channel selection device according to the present invention.
FIG. 2 is a waveform diagram for explaining the muting operation, FIG. 3 is a block diagram of the second embodiment of the television signal channel selection device according to the present invention, and FIG. 7 is a time chart for explaining the adjustment of V pulses in the second embodiment. Figure 5 is a schematic diagram showing a schematic display screen to explain the V flow, and Figure 6 shows the difference between the phase of the vertical synchronization signal of the channel before switching and the phase of the vertical synchronization signal of the channel after switching. FIG. 7 is a schematic diagram showing a schematic display screen for explaining flow planking. 1......Antenna 2...Tuner section 3...
...Selector 6...Synchronization signal separation circuit 9...
・・・・・・・・・Control unit

Claims (2)

[Claims] (1) A tuning means for tuning a television signal; a muting means for muting a tuning output signal from the tuning means; and control means for controlling the muting means so that only the video signal is muted for a predetermined period on the composite video signal obtained as the tuning output signal by the tuning means during the control operation. Television signal selection device. (2) A channel selection means for selecting a television signal, an internal signal generation means for generating a composite video signal with a constant video level as an internal signal, and a channel selection output signal from the channel selection means and generation of the internal signal. a switching means for switching and outputting an internal signal from the means; and a switching means for controlling the tuning operation of the tuning means, and synchronizing a composite video signal obtained as a tuning output signal by the tuning means during the tuning operation. Control is performed to pull in the phase of a synchronizing signal of the internal signal generated by the internal signal generation means into the phase of the signal, and during this pull-in control operation, the switching control means is controlled to select the internal signal. 1. A television signal channel selection device comprising: means.