JP2002325205A - Video wireless transmission and reception system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a video wireless transmission and reception system widening the receiving distance rang of a video receiver without increasing the transmission power of a video transmitter. SOLUTION: A first video receiver 20 is provided with a retransmission circuit part 24 which receives a first high frequency video signal RF1 from a video transmitter 10 and converts it into a second high frequency video signal RF2. When the first high frequency video signal RF1 is received, a second receiver 40 transmits an off-data signal, and when the first high frequency video signal RF1 cannot be received, it transmits an on-data signal, and the second high frequency video signal RF2 is received. When the first video receiver 20 receives the off-data signal, a switch circuit part 32 is turned off to turn off the power source of the retransmission circuit part 24, and when the on-data signal is received, the switch circuit part 32 is turned on to turn on the power source of the retransmission circuit part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video radio transmitting / receiving system comprising a video transmitter for transmitting a video signal by radio and a video receiver for receiving the video signal transmitted by radio. .

[0002]

2. Description of the Related Art FIG. 5 is a block circuit diagram showing a schematic configuration of a conventional video radio communication system. The conventional video wireless communication system 100 shown in FIG. 5 has the following circuit configuration. The video wireless communication system 100 includes a video transmitter 110 and a video receiver 120.

[0005] The video transmitter 110 includes a video signal generation circuit 111, a video transmission circuit 112, and an antenna 113. The output of the video signal generation circuit 111 is connected to the input of the video transmission circuit 112, and the output of the video transmission circuit 112 is connected to the antenna 113.

A video receiver 120 has an antenna 121,
A video receiving circuit unit 122 and a video output terminal 123 are provided. The antenna 121 is connected to the input of the video receiving circuit unit 122, and the output of the video receiving circuit unit 122 is connected to the video output terminal 123.

Next, the operation of the conventional video radio communication system 100 shown in FIG. 5 will be described. Video transmitter 110
In, the video signal output from the video signal generation circuit unit 111 is converted into a high-frequency video signal RF by the video transmission circuit unit 112 and transmitted from the antenna 113 to the video receiver 120.

[0006] In the video receiver 120, the high frequency video signal RF transmitted from the video transmitter 110 is received by the antenna 121. The received high-frequency video signal RF is converted into the original video signal by the video receiving circuit unit 122 and output from the video output terminal 123. And
By connecting a video input terminal of a television (not shown) to the video output terminal 123, the contents of the video signal can be viewed.

As described above, the user operates the video transmitter 1
10 from the video transmitter 110
Can be viewed on the television connected to the video receiver 120 located at a distance from the television receiver.

[0008]

However, the above prior art has the following problems.

That is, the user operates the video transmitter 110
Video radio communication system 100 for viewing a video signal transmitted from a television receiver 120 connected to a video receiver 120 located at a position remote from video transmitter 110
In the case where the video signal from the video transmitter 110 is to be received by the video receiver 120, the transmission power of the video transmission circuit unit 112 needs to be increased. However, when the transmission power of the video transmission circuit unit 112 is increased, the size and power consumption of the video transmission circuit unit 112 are increased, and the size of a power supply circuit unit (not shown) for supplying power to the video transmission circuit unit 112 is also increased. Therefore, the outer shape of the video transmitter 110 also becomes large. further,
Heat generation from the video transmission circuit unit 112 and the power supply circuit unit also increases. Further, for example, when the power supply circuit section is formed of a battery, there is a problem that the battery life is shortened.

[0010] The present invention has been made to solve the above-described problems, and a video signal from a video transmitter 110 can be transmitted to a video receiver without increasing the transmission power of a video transmission circuit unit 112. It is an object of the present invention to provide a video wireless transmission / reception system capable of extending a range in which the H.120 can receive the video.

[0011]

In order to solve the above-mentioned problems, the present invention provides a video transmitter for converting a video signal into a first high-frequency video signal and transmitting the same, and receiving the first high-frequency video signal. In a video wireless transmission / reception system including a first video receiver including a first video reception circuit unit that converts the signal into an original video signal and outputs the video signal, the first video receiver includes the first video receiver. A retransmission circuit unit is provided which converts the high frequency video signal into a second high frequency video signal having a different frequency and retransmits the signal.

Further, according to the present invention, there is provided a signal switching circuit for selecting either the first high-frequency video signal or the second high-frequency video signal, and receiving the high-frequency video signal from the signal switching circuit. A second video receiving circuit for converting the original video signal, a reception detecting circuit for detecting the presence / absence of a video signal from the second video receiving circuit, and a first high-frequency signal switching circuit. Switching to the video signal side, when the reception detection circuit section detects that there is a video signal, the state where the signal switching circuit section is switched to the first high-frequency video signal side is maintained, and the reception detection circuit section has no video signal. And a second control circuit for controlling the signal switching circuit to switch to the second high-frequency video signal side when it is detected. It is.

Further, the present invention provides a data signal generating circuit section in which the second video receiver generates an ON data signal and an OFF data signal for controlling the first video receiver. And a data transmission circuit unit for converting the off data signal into a high-frequency data signal and transmitting the off-data signal when the signal switching circuit unit switches to the first high-frequency video signal side. And controls the data signal generation circuit section to generate the on-data signal when the signal switching circuit section is switched to the second high-frequency video signal side, and the first video receiver includes: A data receiving circuit unit that receives the high-frequency data signal and converts it into an original data signal, a power supply circuit unit that supplies power to each of the circuit units, and from the power supply circuit unit to the retransmission circuit unit. A switch circuit for turning on / off power supply, and a first control for turning on the switch circuit when the data signal is an on data signal and turning off the switch circuit when the data signal is an off data signal And a circuit section.

The present invention also provides a high-frequency amplifier circuit for amplifying the first high-frequency video signal.
A frequency conversion circuit for frequency-converting the amplified first high-frequency video signal into a second high-frequency video signal having a different frequency; and a transmission power amplifying circuit for amplifying the second high-frequency video signal. Power is supplied directly to the high-frequency amplifier circuit and the frequency conversion circuit, and power is supplied from the power supply circuit section to the transmission power amplifier circuit via the switch circuit section. It is.

Further, according to the present invention, the first video receiver notifies the first video receiver of an on / off state of the switch circuit unit.
Is provided.

Further, the present invention is characterized in that the second video receiver comprises a second notifying means for notifying a detection result of the reception detecting circuit section. It is assumed that.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a block circuit diagram showing a schematic configuration of a video radio transmission / reception system according to a first embodiment of the present invention.
FIG. 3 is a flowchart illustrating the operation of the second control circuit unit of the video wireless transmission / reception system according to the first embodiment of the present invention, and FIG. 3 is a video according to the first embodiment of the present invention. FIG. 4 is a flowchart illustrating an operation of a first control circuit unit of the wireless transmission / reception system. Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a block circuit diagram showing a schematic configuration of a video radio transmission / reception system 1 of the present embodiment. The video wireless transmission / reception system 1 of the present embodiment in FIG. 1 has the following circuit configuration. The video wireless transmission / reception system 1
It comprises a video transmitter 10, a first video receiver 20, and a second video receiver 40.

The video transmitter 10 comprises a video signal generation circuit 11, a video transmission circuit 12, and an antenna 13.

An output of the video signal generation circuit 11 is connected to an input of a video transmission circuit 12, and an output of the video transmission circuit 12 is connected to an antenna 13.

The first video receiver 20 has an antenna 2
1, first video receiving circuit section 22, video output terminal 2
3, retransmission circuit section 24, data reception circuit section 30, first control circuit section 31, switch circuit section 32, power supply circuit section 3
3, resistor 34, light emitting diode 35 (first notification means)
And an antenna 36. Then, the retransmission circuit unit 24
Comprises a high-frequency amplifier circuit 25, a frequency conversion circuit 26, and a transmission power amplifier circuit 29. The frequency conversion circuit 26 includes a mixer circuit 27 and a local oscillation circuit 28.

The antenna 21 is connected to the input of the first video receiving circuit 22, and the output of the first video receiving circuit 22 is connected to the video output terminal 23. The power supply circuit section 33 includes the switch circuit section 32 in the retransmission circuit section 24.
Connected through. Further, the power supply circuit unit 33 includes a first video receiving circuit unit 22, a data receiving circuit unit 30, a first control circuit unit 31, a resistor 34, and a light emitting diode 35.
Is directly connected to each of the.

The antenna 21 is connected to a retransmission circuit 24
, And the output of the retransmission circuit section 24 is connected to an antenna 36. Further, the antenna 21 is connected to an input of the data receiving circuit unit 30, and an output of the data receiving circuit unit 30 is connected to the first control circuit unit 31. Further, a switch circuit unit 32 is connected to the first control circuit unit 31, and the port P1 of the first control circuit unit 31 is connected to the switch circuit unit 32.
A series circuit of a resistor 34 and a light emitting diode 35 is connected between the ground and the ground.

In the retransmission circuit section 24, the input side of the retransmission circuit section 24 is connected to the input of the high frequency amplification circuit 25, and the output of the high frequency amplification circuit 25 is supplied to the mixer circuit 27.
The output of the transmission power amplification circuit 29 is connected to the output side of the retransmission circuit section 24 via the input of the transmission power amplification circuit 29. A local oscillation circuit 28 is connected to the mixer circuit 27.

The second video receiver 40 has an antenna 4
1, first bandpass filter 42, second bandpass filter 43, signal switching circuit unit 44, second video receiving circuit unit 45, video output terminal 46, reception detecting circuit unit 4
7. Second control circuit section 48, data signal generation circuit section 4
9, the data transmission circuit unit 50, the resistors 51 and 52, and the light emitting diodes 53 and 54 (second notification means).

The antenna 41 is connected to the respective inputs of the first band-pass filter 42 and the second band-pass filter 43, and the respective outputs of the first band-pass filter 42 and the second band-pass filter 43 are The output of the second video receiving circuit 45 is connected to the input of the second video receiving circuit 45 via the signal switching circuit 44.
Connected to video output terminal 46.

The output of the second video receiving circuit 45 is connected to the input of the receiving detecting circuit 47, and the output of the receiving detecting circuit 47 is connected to the input of the second controlling circuit 48. I have. The output of the second control circuit 48 is
Input of data signal generation circuit 49 and signal switching circuit 4
4, the output of the data signal generation circuit 49 is connected to the input of the data transmission circuit 50, and the output of the data transmission circuit 50 is connected to the antenna 41.

The port P2 of the second control circuit 48
A series circuit of a resistor 51 and a light emitting diode 53 is connected between a and the ground, and a series circuit of a resistor 52 and a light emitting diode 54 is connected between the port P2b of the second control circuit unit 48 and the ground.

Next, the operation of the video radio transmission / reception system 1 of this embodiment shown in FIG. 1 will be described. Video transmitter 1
At 0, the video signal output from the video signal generation circuit unit 11 is converted into a first high-frequency video signal RF1 by the video transmission circuit unit 12, and the first video receiver 20 and the second video Transmitted to receiver 40.

In the first video receiver 20, the first high-frequency video signal RF transmitted from the video transmitter 10
1 is received by the antenna 21. The received first high-frequency video signal RF1 is converted into an original video signal by the first video receiving circuit unit 22, and output from the video output terminal. Then, for example, to the video output terminal 23,
By connecting a video input terminal of a television (not shown), the contents of the video signal can be viewed.

The retransmitting circuit 24 converts the first high-frequency video signal RF1 received by the antenna 21 into a second high-frequency video signal RF2 having a different frequency, and
To the second video receiver 40. That is,
In the retransmission circuit section 24, the input first high-frequency video signal RF1 is amplified by the high-frequency amplifier circuit 25, and then frequency-converted by being mixed with the oscillation frequency signal from the local oscillation circuit 28 by the mixer circuit 27. Further, the signal is amplified by the transmission power amplifier circuit 29 and output as the second high-frequency video signal RF2.

The data receiving circuit unit 30 converts the high-frequency data signal received by the antenna 21 into the original data signal and outputs it to the first control circuit unit 31. Further, power is supplied from the power supply circuit unit 33 to the retransmission circuit unit 24 via the switch circuit unit 32, and the switch circuit unit 32
The power supply from the power supply circuit unit 33 to the retransmission circuit unit 24 is turned on and off. Then, the power is directly supplied from the power supply circuit unit 33 to each of the first video receiving circuit unit 22, the data receiving circuit unit 30, the first control circuit unit 31, the resistor 34, and the light emitting diode 35. .

When the data signal is "ON data" (described later), the first control circuit 31 turns on the switch circuit 32 and sends the signal from the power supply circuit 33 to the retransmission circuit 2
4 is turned on, and when the data signal is “off data” (described later), the switch circuit 32 is turned off to turn off the power supplied from the power supply circuit unit 33 to the retransmission circuit unit 24. Control.

The port P1 of the first control circuit section 31 is provided to notify the ON / OFF state of the switch circuit 32. For example, when the switch circuit 32 is on, the port P1 is set to “H” to turn on the light emitting diode 35, and when the switch circuit 32 is off, the port P1 is turned on.
Is set to “L” and the light-emitting diode 35 is turned off to make the notification.

In the second video receiver 40, the first high-frequency video signal RF1 received by the antenna 41 is passed through the first bandpass filter 42 to the signal switching circuit 4
4 terminal 44a. Further, the second high-frequency video signal RF2 received by the antenna 41 is supplied to the terminal 4 of the signal switching circuit unit 44 via the second bandpass filter 43.
4b.

The signal switching circuit 44 selects one of the first high-frequency video signal RF1 and the second high-frequency video signal RF2, and the second video receiving circuit 45
The high-frequency video signal from the signal switching circuit unit 44 is received, converted into the original video signal, and output from the video output terminal 23. By connecting a video input terminal of a television (not shown) to the video output terminal 23, the contents of the video signal can be viewed.

The reception detection circuit unit 47 detects the presence or absence of a video signal from the second video reception circuit unit 45, and outputs a detection result to the second control circuit unit 48. The data signal generation circuit 49 generates the “on data” and “off data” for controlling the first video receiver 20, and the data transmission circuit 50 generates the data signal generation circuit 4.
9 is converted into a high-frequency data signal and transmitted from the antenna 41 to the first video receiver 20.

The second control circuit 48 switches the signal switching circuit 44 to the first high-frequency video signal RF1 side (terminal 44a
Side, and when the reception detection circuit unit 47 detects that there is a video signal, the state where the signal switching circuit unit 44 is switched to the first high-frequency video signal RF1 side (terminal 44a side) is held. When 47 detects that there is no video signal, it controls the signal switching circuit section 44 to switch to the second high-frequency video signal RF2 side (terminal 44b side).

In the second control circuit 48, the signal switching circuit 44 is connected to the first high-frequency video signal RF1 (terminal 4).
4a), the "off data" is generated when the signal switching circuit 44 switches to the second high-frequency video signal RF2 (terminal 44b). The data signal generation circuit section 49 is controlled so as to cause it.

The port P2a and the port P2b of the second control circuit 48 are provided to notify the detection result of the reception detection circuit 47. For example, the signal switching circuit unit 4
4 is the first high-frequency video signal RF1 side (terminal 44a side)
In the state where the video signal is present, the port P2a is set to “H” and the light emitting diode 5
3 is turned on, and when it is detected that there is no video signal, the port P2a is set to "L" and the light emitting diode 53 is turned off to perform the above-described notification.

When the video signal is detected while the signal switching circuit 44 is switched to the second high-frequency video signal RF2 (terminal 44b), the port P
2b is set to “H”, the light emitting diode 54 is turned on, and when it is detected that there is no video signal, the port P2b is set to “L”.
The notification is made by turning off the light emitting diode 54.

FIG. 2 is a flowchart for explaining the operation of the second control circuit unit 48 of the video wireless transmission / reception system 1 of the present embodiment. The second control circuit unit 48 is constituted by, for example, a microcomputer. The operation of the control circuit unit 48 when the second control circuit unit 48 is configured by a microcomputer will be described below with reference to FIG.

In step S1, the signal switching circuit 4
4 is the first high-frequency video signal RF1 side (terminal 44a side)
After that, the process proceeds to step S2.

In step S2, the reception detection circuit unit 4
Check whether the detection result of 7 is a video signal or not,
If there is a video signal, the process proceeds to step S3. If there is no video signal, the process proceeds to step S4.

In step S3, the data signal generation circuit 49 is controlled to generate "off data", the port P2a is set to "H" and the port P2b is set to "L", the light emitting diode 53 is turned on, and the light emitting diode is turned on. When the signal switching circuit section 44 is switched off to the first high-frequency video signal RF1 side (terminal 44a side), it is notified that a video signal is detected.

In step S4, after controlling the data signal generating circuit 49 so as to generate "ON data", the signal switching circuit 44 is switched to the second high-frequency video signal RF.
Switch to the second side (terminal 44b side) and proceed to step S5.

In step S5, the reception detection circuit unit 4
Check whether the detection result of 7 is a video signal or not,
If there is a video signal, the process proceeds to step S6. If there is no video signal, the process proceeds to step S7.

In step S6, the port P2a is set to "L" and the port P2b is set to "H", the light emitting diode 53 is turned off, the light emitting diode 54 is turned on, and the signal switching circuit section 44 is switched to the second high-frequency video signal RF2 side. When the terminal is switched to (terminal 44b side), it is notified that a video signal is detected.

In step S7, the data signal generating circuit 49 is controlled to generate "off data", the port P2a is set to "L" and the port P2b is set to "L", the light emitting diode 53 is turned off, and the light emitting diode is turned off. The reception detection circuit unit 47 turns off the first high-frequency video signal RF1 and the second high-frequency video signal RF.
2 that no video signal has been detected.

As described above, the second control circuit unit 48
The signal switching circuit section 44 is switched to the first high-frequency video RF1 signal side (terminal 44a side). (Terminal 44a side), and when the reception detection circuit unit 47 detects that there is no video signal, the signal switching circuit unit 44 is switched to the second high-frequency video signal RF2 side (terminal 44b side). Control.

In the second control circuit unit 48, the signal switching circuit unit 44 controls the first high-frequency video signal RF1 side (terminal 4).
4a), the "off data" is generated when the signal switching circuit 44 switches to the second high-frequency video signal RF2 (terminal 44b). The data signal generation circuit section 49 is controlled so as to cause it.

The second control circuit 48 sets the detection results of the reception detection circuit 47 to, for example, "H" and "L" for the port P2a and the port P2b, and sets the resistance to the port P2a and the port P2b, respectively. The notification is made by turning on or off the light emitting diode 53 and the light emitting diode 54 connected via the resistor 51 and the resistor 52.

Therefore, the user of the second video receiver 40 can easily confirm the quality of the set position of the second video receiver 40 by turning on or off the light emitting diodes 53 and 54. it can.

That is, the light emitting diode 53 lights up,
When the light emitting diode 54 is turned off (this state is referred to as “state 1”), the power of the retransmission circuit unit 24 of the first video receiver 20 is turned off, and the second video receiver 40 is turned off.
Receives the first high-frequency video signal RF1 from the transmitter 10, it can be seen that the second video receiver 40 is at the best position.

When the light emitting diode 53 is turned off and the light emitting diode 54 is turned on (this state is referred to as “state 2”).
), The retransmission circuit unit 24 of the first video receiver 20
Is turned on, and the second video receiver 40
Since the second high-frequency video signal RF2 from the first video receiver 20 is being received, the second video receiver 40 is in the next best position after the “state 1”. It can be seen that it is preferable to move the position of the second video receiver 40 so as to be in the “state 1” in order to reduce the power consumption of the device 20.

When both the light emitting diode 53 and the light emitting diode 54 are turned off (this is referred to as “state 3”).
), The second video receiver 40 receives neither the first high-frequency video signal RF1 from the transmitter 10 nor the second high-frequency video signal RF2 from the first video receiver 20. It can be seen that it is necessary to bring the second video receiver 40 closer to either the transmitter 10 or the first video receiver 20 so as to be in the “state 1” or the “state 2”.

FIG. 3 is a flowchart for explaining the operation of the first control circuit unit 31 of the video wireless transmission / reception system 1 of the present embodiment. The first control circuit unit 31 is configured by, for example, a microcomputer. The operation of the control circuit unit 31 when the first control circuit unit 31 is configured by a microcomputer will be described below with reference to FIG.

In step S1, it is checked whether a data signal has been input from the data receiving circuit unit 30, and
If the data signal is input, the process proceeds to step S2.

In step S2, it is checked whether or not the data signal is "on data". If the data signal is "on data", the process proceeds to step S3, and if the data signal is not "on data", the process proceeds to step S4. .

In step S3, the switch circuit unit 3
2 is turned on, the power supply from the power supply circuit 33 to the retransmission circuit 24 is turned on, the port P1 is set to “H”, the light emitting diode 35 is turned on, and the switch circuit 32 is turned on. Announce.

In step S4, it is checked whether or not the data signal is "off data". If the data signal is "off data", the process proceeds to step S5.

In step S5, the switch circuit unit 3
2, the power supply from the power supply circuit unit 33 to the retransmission circuit unit 24 is turned off, the port P1 is set to "L", the light emitting diode 35 is turned off, and the switch circuit unit 32 is off. Announce.

As described above, the first control circuit unit 31
When the data signal is “on data”, the switch circuit unit 32 is turned on, and the data signal is “off data”.
Is controlled so that the switch circuit unit 32 is turned off.

The first control circuit section 31 sets the on / off state of the switch circuit section 32 to, for example, “H” and “L” for the port P 1, and the light emission connected to the port P 1 via the resistor 34. The notification is made by turning on or off the diode 35.

As described above, in the video radio transmission / reception system 1 of the present embodiment, the distance between the video transmitter 10 and the second video receiver 40 is different from the distance between the video transmitter 10 and the first video receiver 20. If the distance is longer than the distance, that is, the first high-frequency video signal RF1 from the video transmitter 10 is
In the case where the second video receiver 40 has difficulty in receiving compared to the first video receiver 20, the following operation is performed.

When the second video receiver 40 can directly receive the first high-frequency video signal RF1 from the video transmitter 10, the power supply of the retransmission circuit unit 24 provided in the first video receiver 20 Turn off. Further, for example, when the position of the second video receiver 40 is moved and the second video receiver 40 cannot directly receive the first high-frequency video signal RF1 from the video transmitter 10 Turns on the power of the retransmission circuit unit 24 provided in the first video receiver 20, operates the retransmission circuit unit 24,
The second video receiver 40 receives the retransmitted second high-frequency video signal RF2. That is, the power supply of the retransmission circuit unit 24 provided in the first video receiver 20 is turned on only when necessary, so that the power supply circuit The power consumption of the unit 33 can be reduced.

[Second Embodiment] FIG. 4 is a block circuit diagram showing a schematic configuration of a video radio transmission / reception system according to a second embodiment of the present invention. Compared with the block circuit diagram showing a schematic configuration of the video wireless transmission / reception system according to the first embodiment of the present invention described in FIG.
In the first video receiver 20, only a circuit to be controlled to turn on / off the power supply from the power supply circuit unit 32 to the retransmission circuit unit 24 is different. That is, the video transmitter 10 and the second video receiver 40 in the video wireless transmission / reception system 2 in FIG. 4 are the same as those in FIG. Also, the first
The operation of the first control circuit unit 31 of the video receiver 20 of
The operation of the second control circuit unit 48 of the second video receiver 40 is the same as that of FIG.

Therefore, in the first video receiver 20, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. Parts different from FIG. 1 will be described below. In FIG. 1, a high-frequency amplifier circuit 2 constituting a retransmission circuit unit 24 from a power supply circuit unit 33 via a switch circuit unit 32
5, while the power is supplied to all the circuits of the frequency conversion circuit 26 and the transmission power amplification circuit 29, in the first video receiver 20 of the video wireless transmission / reception system 2 of FIG. The power is directly supplied from 33 to the high-frequency amplifier circuit 25 and the frequency conversion circuit 26,
Power is supplied from the power supply circuit section 33 to the transmission power amplifier circuit 29 via the switch circuit section 32.

That is, in the [first embodiment], the power supply to the entire retransmission circuit unit 24 is turned on / off by the switch circuit unit 32, whereas in the present embodiment, the retransmission circuit unit 24 is Of the constituent circuits, only the power supply of the transmission power amplifier circuit 29, which consumes relatively large power, is turned on and off. Generally, local oscillation circuit 2 after power-on
The operation of the retransmission circuit unit 24 is not stable until the oscillation of the clock signal 8 is stabilized.
Since the power is always supplied to the frequency conversion circuit 26 (mixer circuit 27, local oscillation circuit 28),
Embodiment], the time from when the power is turned on to when the operation of the retransmission circuit unit 24 is stabilized can be shortened.

As described above, in the embodiment of the present invention, one first video receiver 20 is
Although the case where the number of the second video receiver 40 is one is shown, the present invention is not limited thereto.
Of the video receivers 40 may be used in plurality.

Further, the case where the notification is made by using the light emitting diode has been described. However, the present invention is not limited to this, and other means that can notify the user, such as a buzzer, may be used.

[0072]

As described above, the present invention relates to a video transmitter for converting a video signal into a first high-frequency video signal and transmitting the converted video signal, and a video signal for receiving the first high-frequency video signal. And a first video receiver having a first video receiver circuit that converts and outputs the first video receiver circuit, wherein the first video receiver converts the first high-frequency video signal into a signal having a frequency A retransmission circuit unit for converting the signal into a different second high-frequency video signal and retransmitting the signal is provided.

Therefore, according to the present invention, the first video receiver receives the first high-frequency video signal from the video transmitter and converts the first high-frequency video signal into a second high-frequency video signal having a different frequency. By retransmitting, the transmission distance range of the video signal from the video transmitter can be expanded without increasing the transmission power of the video transmitter.

Furthermore, since the transmission distance range of the video signal from the video transmitter is expanded without increasing the transmission power of the video transmitter, the power consumption and heat generation of the video transmitter can be suppressed. Further, for example, when the power supply circuit section of the video transmitter is formed of a battery, problems such as shortened battery life can be solved.

Further, according to the present invention, there is provided a signal switching circuit for selecting one of the first high-frequency video signal and the second high-frequency video signal, and receiving the high-frequency video signal from the signal switching circuit. A second video receiving circuit for converting the original video signal, a reception detecting circuit for detecting the presence / absence of a video signal from the second video receiving circuit, and a first high-frequency signal switching circuit. When the reception detection circuit unit detects that there is a video signal, the state is switched to the first high-frequency video signal side when the reception detection circuit unit detects that there is a video signal. And a second control circuit for controlling the signal switching circuit to switch to the second high-frequency video signal side when it is detected. It is.

Therefore, according to the present invention, when the distance between the video transmitter and the second video receiver is longer than the distance between the video transmitter and the first video receiver, The first high-frequency video signal from the video transmitter, compared to the first video receiver, when the second video receiver is difficult to receive, the second video receiver, If the first high-frequency video signal cannot be directly received from the video transmitter, the second high-frequency video signal retransmitted from the first video receiver is received.

That is, the second video receiver receives the video signal from the video transmitter via the first video receiver, thereby increasing the transmission power of the video transmitter. The transmission range of the video signal from the video transmitter can be extended.

Furthermore, since the transmission distance range of the video signal from the video transmitter is expanded without increasing the transmission power of the video transmitter, power consumption and heat generation of the video transmitter can be suppressed. Further, for example, when the power supply circuit section of the video transmitter is formed of a battery, problems such as a shortened battery life can be solved.

Further, the present invention provides a data signal generating circuit for generating an on data signal and an off data signal for controlling the first video receiver, wherein the second video receiver includes: And a data transmission circuit unit for converting the off data signal into a high-frequency data signal and transmitting the off-data signal when the signal switching circuit unit switches to the first high-frequency video signal side. And controls the data signal generation circuit section to generate the on-data signal when the signal switching circuit section is switched to the second high-frequency video signal side, and the first video receiver includes: A data receiving circuit unit that receives the high-frequency data signal and converts it into an original data signal, a power supply circuit unit that supplies power to each of the circuit units, and from the power supply circuit unit to the retransmission circuit unit. A switch circuit for turning on / off power supply, and a first control for turning on the switch circuit when the data signal is an on data signal and turning off the switch circuit when the data signal is an off data signal And a circuit section.

Therefore, according to the present invention, when the distance between the video transmitter and the second video receiver is longer than the distance between the video transmitter and the first video receiver, In the case where the second high-frequency video signal from the video transmitter is more difficult to receive by the second video receiver than by the first video receiver, the following operation is performed.

When the second video receiver can directly receive the first high-frequency video signal from the video transmitter, the power of the retransmission circuit is turned off. Also,
For example, when the position of the second video receiver is moved and the second video receiver cannot directly receive the first high-frequency video signal from the video transmitter, The power of the retransmission circuit unit is turned on, and the retransmission circuit unit is operated, so that the second video receiver receives the retransmitted second high-frequency video signal. That is, by turning on the power of the retransmission circuit unit provided in the first video receiver only when necessary, compared with the case where the power of the retransmission circuit unit is always on,
The power consumption of the first video receiver can be reduced.

Then, the second video receiver receives the video signal from the video transmitter via the first video receiver, thereby increasing the transmission power of the video transmitter. The transmission range of the video signal from the video transmitter can be extended.

Further, since the transmission distance range of the video signal from the video transmitter is expanded without increasing the transmission power of the video transmitter, power consumption and heat generation of the video transmitter can be suppressed. Further, for example, when the power supply circuit sections of the video transmitter and the first video receiver are formed of batteries, problems such as shortening of battery life can be solved.

Further, according to the present invention, the retransmission circuit section may include a high frequency amplifier circuit for amplifying the first high frequency video signal,
A frequency conversion circuit for frequency-converting the amplified first high-frequency video signal into a second high-frequency video signal having a different frequency; and a transmission power amplifying circuit for amplifying the second high-frequency video signal. Power is supplied directly to the high-frequency amplifier circuit and the frequency conversion circuit, and power is supplied from the power supply circuit section to the transmission power amplifier circuit via the switch circuit section. It is.

Therefore, according to the present invention, only the power supply of the transmission power amplifier circuit which consumes relatively large power among the circuits constituting the retransmission circuit section is turned on / off.
Generally, the operation of the retransmission circuit unit is not stable during the period from when the power is turned on until the oscillation of the local oscillation circuit is stabilized.
In the present embodiment, since the power is always supplied to the high-frequency amplifier circuit and the frequency conversion circuit (mixer circuit, local oscillation circuit), the time from when the power is turned on to when the operation of the retransmission circuit section is stabilized is obtained. Can be shortened.

That is, as described above, for example, the position of the second video receiver is moved, so that the second video receiver receives the first video signal from the video transmitter.
If you can no longer directly receive the high-frequency video signal of
By operating the retransmission circuit unit, the time until the retransmitted second high-frequency video signal can be received can be shortened, and interruption of images and sounds can be improved.

Further, according to the present invention, the first video receiver notifies the first video receiver of an on / off state of the switch circuit section.
Is provided.

Therefore, according to the present invention, since the user of the first video receiver can easily confirm the on / off operation of the retransmitting unit, the power of the retransmitting unit is turned on. If it is confirmed that the video transmitter, the first video receiver and the second video receiver to move the position between each other, the power of the retransmission unit is turned off, the first The power consumption of the video receiver can be reduced.

Further, the present invention is characterized in that the second video receiver is provided with second notifying means for notifying the detection result of the reception detecting circuit section. It is assumed that.

Therefore, according to the present invention, the user of the second video receiver can easily confirm the reception status of the second video receiver, and the video transmitter and the second When the position between the first video receiver and the second video receiver is moved, it is possible to know whether or not the installation locations are appropriate.

[Brief description of the drawings]

FIG. 1 is a block circuit diagram showing a schematic configuration of a video wireless transmission / reception system according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of a second control circuit unit of the video wireless transmission / reception system according to the first embodiment of the present invention.

FIG. 3 is a flowchart illustrating an operation of a first control circuit unit of the video wireless transmission / reception system according to the first embodiment of the present invention.

FIG. 4 is a block circuit diagram showing a schematic configuration of a video wireless transmission / reception system according to a second embodiment of the present invention.

FIG. 5 is a block circuit diagram showing a schematic configuration of a conventional video wireless transmission / reception system.

[Explanation of symbols]

 1, 2 video wireless transmission / reception system 10 video transmitter 11 video signal generation circuit unit 12 video transmission circuit unit 13 antenna 20 first video receiver 21 antenna 22 first video reception circuit unit 23 video output terminal 24 retransmission circuit unit Reference Signs List 25 high-frequency amplifier circuit 26 frequency conversion circuit 27 mixer circuit 28 local oscillation circuit 29 transmission power amplifier circuit 30 data reception circuit section 31 first control circuit section 32 switch circuit section 33 power supply circuit section 34 resistor 35 light-emitting diode (first notification Means) 36 antenna 40 second video receiver 41 antenna 42 first bandpass filter 43 second bandpass filter 44 signal switching circuit unit 45 second video reception circuit unit 46 video output terminal 47 reception detection circuit unit 48 Second control circuit section 49 Data signal generation circuit section 50 data transmission circuit section 51, 52 resistance 53, 54 light emitting diode (second notification means)

Claims (6)

[Claims] 1. A video transmitter for converting a video signal into a first high-frequency video signal and transmitting the first high-frequency video signal, and a first transmitting and receiving the first high-frequency video signal after converting the video signal into an original video signal In a wireless video transmission / reception system including a first video receiver including a video reception circuit unit, the first video receiver converts the first high-frequency video signal into a second high-frequency video signal having a different frequency. A video wireless transmission / reception system comprising a retransmission circuit unit for retransmission. 2. The first high-frequency video signal or the second high-frequency video signal.
A signal switching circuit for selecting one of the high-frequency video signals, a second video receiving circuit for receiving the high-frequency video signal from the signal switching circuit and converting it to the original video signal, (2) a reception detection circuit for detecting the presence or absence of a video signal from the video reception circuit, and the signal switching circuit for switching to the first high-frequency video signal side, and the reception detection circuit detects that there is a video signal Hold the state in which the signal switching circuit is switched to the first high-frequency video signal side, and when the reception detection circuit detects that there is no video signal, the signal switching circuit is switched to the second high-frequency video signal side. 2. The video radio transmission / reception system according to claim 1, further comprising a second video receiver including a second control circuit for controlling the switching. 3. The second video receiver includes a data signal generation circuit for generating an on data signal and an off data signal for controlling the first video receiver, and a high frequency data signal. And a data transmission circuit section for converting and transmitting, the second control circuit section generates the off data signal when the signal switching circuit section is switched to the first high-frequency video signal side, Controlling the data signal generation circuit unit to generate the on-data signal when the signal switching circuit unit switches to the second high-frequency video signal side; A data receiving circuit unit for receiving a signal and converting it to an original data signal; a power supply circuit unit for supplying power to each of the circuit units; and turning off power supply from the power supply circuit unit to the retransmission circuit unit. A switch circuit unit that turns off, a first control circuit unit that turns on the switch circuit unit when the data signal is an on data signal, and turns off the switch circuit unit when the data signal is an off data signal; The video wireless transmission / reception system according to claim 2, further comprising: 4. A high-frequency amplifier circuit for amplifying the first high-frequency video signal, wherein the retransmission circuit unit converts the frequency of the amplified first high-frequency video signal into a second high-frequency video signal having a different frequency. A frequency conversion circuit and a transmission power amplification circuit for amplifying the second high-frequency video signal; power is directly supplied from the power supply circuit unit to the high-frequency amplification circuit and the frequency conversion circuit; The video wireless transmission / reception system according to claim 3, wherein power is supplied to the power amplification circuit via the switch circuit unit. 5. The video wireless transmission / reception system according to claim 3, wherein the first video receiver includes a first notification unit that notifies an on / off state of the switch circuit unit. 6. The apparatus according to claim 2, wherein the second video receiver includes a second notification unit that notifies a detection result of the reception detection circuit unit. A video wireless transmission / reception system as described.