JPH04328971A - Av system - Google Patents

Abstract

PURPOSE:To select a channel of a satellite broadcast program while being resident at an installation position of a conventional type television receiver and to prevent viewing of a ground broadcast program of a viewer of a BS built-in television receiver from being disturbed. CONSTITUTION:When a BS built-in television receiver 1 and a conventional television receiver 2 are interconnected by a video cable 6 and a ground broadcast program is viewed by the BS built-in television receiver 1, a satellite broadcast program is to be viewed by the conventional television receiver 2. A microcomputer 14 detects the connection/disconnection of a cable core wire ground resistor R4 to/from a synchronizing signal extraction section 10 by turning off/on a channel changeover switch SW interposed in the video cable in the vicinity of the conventional television receiver 2 to switch the reception channel of a BS tuner 2.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a type of television receiver with a built-in BS tuner (TV with built-in BS),
This invention relates to an AV (audio-visual) system that is connected to a regular type television receiver (regular type television) that does not have a built-in BS tuner using a video cable.

0002

[Prior Art] When viewing satellite broadcasting on a regular TV using a TV with built-in BS, the video output terminal of the TV with built-in BS and the video input terminal of the normal TV are connected with a video cable, and the TV with built-in BS To guide satellite broadcast programs selected and received by a BS tuner to a regular TV via a video cable. In such cases, the television with built-in BS and the regular television are usually installed in different rooms. In addition to the BS tuner, TVs with built-in BS have UHF/
It also has a built-in VHF tuner, so even when you are watching satellite broadcast programs on a regular TV, you can still watch terrestrial broadcast programs on a TV with built-in BS.

[0003] In such a case, when a regular TV viewer wants to change the receiving channel of a satellite broadcast program, he must go to the location where the TV with built-in BS is installed,
Channels can be changed by operating the TV's remote controller or operating the TV's control panel (key switch).

0004

[Problems to be Solved by the Invention] However, it is very troublesome for the user to have to move from the location where the regular TV is installed to the location where the BS built-in TV is installed each time the user changes channels. In addition, in order to check the content of the satellite broadcast program on the receiving channel, it is necessary to check the satellite broadcast program on the switched channel on the TV with built-in BS on the spot. For those who were watching the program, their viewing of the program will be interrupted.

[0005] The present invention was devised in view of the above circumstances, and an object of the present invention is to make it possible to switch channels of satellite broadcast programs while remaining at the location where a regular television is installed.

[0006]

[Means for Solving the Problems] The AV system according to the present invention is an AV system in which a TV with built-in BS and a regular TV are connected by a video cable, and the channel is switched to the video cable in the vicinity of the regular TV. In addition, the TV with built-in BS is equipped with a means for detecting a change in the video signal level due to switching of the switch and updating and switching the receiving channel of the BS tuner. be.

[0007]

[Operation] A cable core grounding resistor is connected to the video input terminal of a regular TV to which the video cable is connected, but when the channel switching switch inserted in the video cable is opened, current flows through the grounding resistor. Therefore, the level of the video signal increases on the TV with built-in BS. This change in the video signal level is detected on the BS built-in television side and the reception channel of the BS tuner is switched. Since the above-mentioned switch is installed in the video cable near the regular TV, viewers who are watching satellite programs on a regular TV can change the channel of the satellite broadcast program while they are there. You can switch.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the AV system according to the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a conceptual diagram showing a schematic configuration of an AV system according to an embodiment.

[0010] In the figure, TV1 is a TV with built-in BS;
TV2 is a regular TV, 2 is a BS tuner for the BS built-in TV TV1, 4 is a UHF/VHF tuner for the BS built-in TV TV1, and 6 is a video cable (RF coaxial cable) that connects the BS built-in TV TV1 and the normal TV TV2. It is. The TV with built-in BS TV1 and the regular TV TV2 are installed in different rooms.

FIG. 1 is a block circuit diagram showing the electrical configuration of the main parts of an AV system according to an embodiment.

The BS built-in television TV1 includes the following elements. Q1 is the video output buffer transistor, R1 is its emitter grounded resistance, R2 is the output resistance, C1
is a coupling capacitor, R3 is a grounding resistor, C2 is a capacitor for cutting DC components, 8 is a video output terminal for the RF signal, 1
0 is a synchronization signal extraction section, 12 is a one-shot multivibrator, 14 is a microcomputer, 14a is video output level monitoring means, and 14b is channel switching signal generation means.

Reference numeral 16 denotes a video input terminal in the normal type television TV2, and R4 represents a cable core grounding resistance (75Ω) connected to the video input terminal 16.

[0014] Channel switching is performed at a point in the middle of the core wire of the video cable 6 that connects the video output terminal 8 of the BS built-in television TV1 and the video input terminal 16 of the regular television TV2, and near the regular television TV2. A switch SW is provided for this purpose. This channel changeover switch SW is normally closed.

Next, the operation of the AV system having the above configuration will be explained based on the timing charts of FIGS. 3 and 4.

[0016]Currently, viewers of TV1 with built-in BS
A viewer of a regular TV TV2 is watching a terrestrial broadcast program received on HF/VHF tuner 4, and taking advantage of the fact that BS tuner 2 is vacant, a viewer of a regular TV TV2 is watching a satellite broadcast program received on BS tuner 2 using a video cable. Suppose that the program is received from the BS built-in television TV1 to the regular television TV2 via the BS TV 6 and is viewed on the regular television TV2.

When the channel switching switch SW is closed, the cable core grounding resistor R4 is connected to the video input terminal 16, and the video signal output from the video output buffer transistor Q1 is synchronized with the synchronization signal. The level of the video signal S1 flowing into the synchronization signal extraction section 10 is as follows:
As shown in the first half of FIG. 3, it has become smaller.

The synchronization signal extractor 10 is supplied with a synchronization signal separated from the video signal by a synchronization separation circuit (not shown) as the extraction timing signal S2, but since the level of the video signal S1 is low, the video output buffer The synchronizing signal is not extracted from the video signal S1 flowing in from the transistor Q1.

When a user viewing the regular television TV2 wants to change the receiving channel of a satellite broadcast program, he opens the channel changeover switch SW once and then closes it again.

[0020] That is, if the user
Channel switching switch SW at the installation location of V2
When turned off, the cable core grounding resistor R4 on the normal type television TV2 side, which had been connected via the core wire of the video cable 6, is disconnected from the video output terminal 8 of the BS built-in television TV1. As a result, all of the video signal output from the video output buffer transistor Q1 will flow into the synchronization signal extraction section 10, and the level of the video signal S1 will increase as shown in the latter half of FIG. (approximately twice as much).

[0021] Then, the synchronizing signal extracting section 10 can extract the synchronizing signal S3 from the video signal S1 at the timing of inputting the extracting timing signal S2.

[0022] Then, this sampling synchronization signal S3 is input to the one-shot multivibrator 12 at the next stage.

Next, one-shot multivibrator 1
2 and the operation of the microcomputer 14 will be explained with reference to FIG.

Assuming that the channel changeover switch SW is turned off and instantaneously returns to the on state, only one sampling synchronization signal S3 will be output, as shown in the first half of FIG. In this case, the one-shot multivibrator 12 generates a rectangular wave signal S that rises to the "H" level at the timing of the rise of the sampling synchronization signal S3, and falls to the "L" level after a certain period of time T has elapsed.
4 is output to the microcomputer 14.

The video output level monitoring means 14a in the microcomputer 14 monitors this rectangular wave signal S4, and controls the channel switching signal generating means 14b at the falling timing of the rectangular wave signal S4 to generate the channel switching signal S4.
5 to the BS tuner 2. Channel switching signal S
The BS tuner 2 that receives the input signal 5 can switch the reception channel to the plus side or the minus side.

However, the time width T of the rectangular wave signal S4 outputted by the one-shot multivibrator 12 is set longer than the synchronizing signal pulse interval of 16.7 msec, and normally the channel switching switch SW is It does not return to the ON state instantly, but remains OFF for a certain amount of time. In this case, as shown in the second half of FIG. 4, a plurality of sampling synchronization signals S3 will be output, but in this case as well, after a certain period of time T has elapsed since the last sampling synchronization signal S3 was output. The rectangular wave signal S4 falls, and the channel switching signal S5 is output at the timing of the falling edge, and the BS
The reception channel by tuner 2 is switched.

As described above, since the channel switching switch SW is interposed in the video cable 6 in the vicinity of the regular television TV2, a user who is viewing a satellite broadcast program on the regular television TV2 can change the channel. By turning the changeover switch SW off and then back on,
It is possible to remotely control the BS tuner 2 and switch the reception channel of a satellite broadcast program while being present. Therefore, there is no need to move to the location where the BS built-in television TV1 is installed, unlike in the past.

[0028] Turning off/off the channel switching switch SW
By repeating turning ON, the reception channel can be updated.

[0029] You can also confirm whether the switched satellite broadcast program is the desired program on the screen displayed on the regular TV TV2.
/B terrestrial broadcast program received by VHF tuner 4
This does not interfere with the viewing of those who are viewing the TV on the S built-in TV TV1.

[0030]

[Effects of the Invention] As described above, according to the present invention, it is possible to change the channel of a satellite broadcast program while staying at the place where a regular TV is installed, and to check whether the changed program is the desired one. Since the user can check the status on a regular TV, there is no need to interfere with the viewing of terrestrial broadcast programs by viewers of TVs with built-in BS.

[Brief explanation of drawings]

FIG. 1 is a block circuit diagram showing the electrical configuration of main parts of an AV system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram showing a schematic configuration of an AV system according to an embodiment.

FIG. 3 is a timing chart for explaining the operation of the embodiment.

FIG. 4 is a timing chart for explaining the operation of the embodiment.

[Explanation of symbols]

TV1 TV with built-in BS TV2 Regular TV 2 BS tuner 4 UHF/VHF tuner 6 Video cable 8 Video output terminal 10 Sync signal extractor 12 One-shot multivibrator 14
Microcomputer 14a Video output level monitoring means 14b Channel switching signal generation means 16 Video input terminal R4 Cable core grounding resistance

Claims (1)

[Claims] [Claim 1] An AV system in which a TV with built-in BS and a regular TV are connected by a video cable, in which a switch for switching channels is interposed in the video cable near the normal TV, and a switch for switching channels is provided on the TV with built-in BS. The AV system is characterized in that the AV system is equipped with means for detecting a change in the video signal level due to switching of the switch and updating and switching the receiving channel of the BS tuner.