JPH057330A - Monitor camera system - Google Patents

Abstract

PURPOSE:To easily execute the installation and the increase of a video camera and the change of an installing place, and simultaneously, to execute monitoring from plural places without requiring any special controller and in addition, without limiting a monitoring place in a monitor camera system. CONSTITUTION:Video signals outputted from plural video cameras 12a to 12n are frequency-modulated, and the output video signals from every video camera 12a to 12n are superposed on one cable 10. Besides, the title monitor camera system is constituted so as to execute the monitoring by connecting an existing television receiver to the above-mentioned cable 10 by making this modulation system coincide with the broadcast system of television.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surveillance camera system using a video camera.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing a surveillance camera system using a conventional video camera.
1a to 1n are video cameras, 2a to 2n are video cables, 3 is a controller, 4 is a monitor TV, and 5 is a VTR.
Is.

The video cameras 1a to 1n are individually connected to the controller 3 via video cables 2a to 2n, and the video cameras 1a to 1n are also connected.
Power is supplied from the controller 3 via the video cables 2a to 2n so as to be superimposed on the video signal. Further, the controller 3 is configured to automatically switch the output video signals from the video cameras 1a to 1n or select only a specified video camera.

Next, the operation of the above configuration will be described. For example, the video camera 1a designated and selected by the controller 3 or automatically switched.
The output video signal from any one of
It is displayed on the monitor television 4 and monitored, and is recorded on the VTR 5.

[0005]

Since the conventional surveillance camera system using a video camera is constructed as described above, a video cable is required for each video camera, so it is necessary to add or change the installation location. If so, the wiring work will increase. Further, since the output of each video camera must be switched by a controller and a plurality of video cables are required, there is a problem that the monitoring place by each video camera is naturally restricted.

In addition, a controller is indispensable for superimposing a video signal and a power supply on the video cable, and when the cable length becomes long, the DC resistance value of the cable cannot be ignored. there were.

The present invention has been made in order to solve the above problems, and it is possible to easily install, add or change the location of a video camera, and further,
An object of the present invention is to provide a surveillance camera system capable of setting a plurality of surveillance locations by a video camera and capable of performing predetermined surveillance without requiring a special controller.

[0008]

A surveillance camera system according to the present invention modulates output video signals from a plurality of video cameras with different frequencies for each video camera, and
It is characterized in that it is configured to be superposed on a book cable.

The surveillance camera system according to claim 2 is
The modulation system of the video signal is matched with the broadcasting system of the television so that the existing television receiver can be connected to the cable.

[0010]

According to the present invention, the video signals output from the plurality of video cameras are modulated with different frequencies, and the output signals from the plurality of video cameras are superimposed on one cable, whereby the video cameras are Wiring work is easy when changing the installation location or adding more.

Also, by matching the modulation system of the output video signal with the broadcasting system of the television, it is possible to use the existing television receiver and to monitor a plurality of places at any place without using a special controller. Can be done.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 is a block diagram showing a surveillance camera system according to an embodiment of the present invention. In FIG.
0 is a cable, 11a to 11n are mixers, 12a to 12
n is a video camera, and each of these video cameras 12a
-12n is the cable 1 through the mixers 11a-11n.
0, and each video camera 12a-1
The video signals output from 2n are modulated at different frequencies.

Next, the operation of the above configuration will be described. Since the output video signals of the video cameras 12a to 12n are modulated at different frequencies, one cable 1
It is possible to superimpose signals from a plurality of video cameras 12a to 12n on 0. Therefore, when installing a surveillance camera system using a video camera, if the cable 10 and mixers 11a to 11n are installed,
After that, it is easy to add more video cameras and change the installation location.

FIG. 2 is a block diagram showing a surveillance camera system according to another embodiment of the present invention, and FIG. 3 is a block diagram showing a structure of a modulator for modulating an output video signal from a video camera into an RF signal. 2, parts that are the same as or equivalent to those of the embodiment shown in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted.

In FIG. 2, 13a and 13b are demultiplexers,
Reference numeral 14 is a distributor, and 15a to 15c and 16 are monitor televisions. Further, in FIG. 3, 21 is a filter, 22
Is a video modulation circuit, 23 is an oscillator, 24 is a video amplifier, and 25 is a video signal output from a video camera.

Next, the operation of FIG. 3 will be described. The output video signal 25 from the video camera passes through the video amplifier 24 and is fed to the oscillator 2 in the video modulation circuit 22.
3 is output, and unnecessary frequency components are removed by the filter 21 to obtain the RF output 20. Therefore, in the system shown in FIG. 2, the video cameras 12a-1
The output of 2n becomes the RF output 20. That is, the modulator shown in FIG. 3 is provided in each of the video cameras 12a to 12n, but of course, a similar modulator may be provided outside the video camera.

Here, the frequency of the oscillator 23 is adjusted to the broadcasting system, and each of the video cameras 12a-12.
By varying the frequency of the oscillator 23 corresponding to up to n, the RF signals taken out by the demultiplexers 13a and 13b on the cable 10 are distributed via the distributor 14 to the plurality of monitor televisions 15a to 15c for each video camera. Can be monitored. Also, in different places, the monitor television 16 can similarly monitor each video camera. A video camera is used as the monitor televisions 15a to 15c.
Switching with 16 and 16 may be performed simply by selecting a channel as in a normal television receiver.

In the above embodiment, the case where the video signals output from the plurality of video cameras 12a to 12n are superimposed on one cable 10 has been described.
An audio signal may be superimposed together with this video signal. That is, as shown in FIG. 4, each of the video cameras 12a-1a
2n respectively connected to the microphones 17a to 17n and simultaneously modulating the audio signals and the video signals from the microphones 17a to 17n to output the video signals and the microphones from the video cameras 12a to 12n on one cable 10. The audio signals from 17a to 17n can be superimposed.

FIG. 5 is a block diagram showing a modulation system in the broadcasting system. In FIG. 5, 26 and 27 are voice synthesis circuits, 28 is a voice FM modulation circuit, 29 is a 4.5 MHz oscillator, and 30 is voice from a microphone. It is a signal.

In FIG. 5, the audio signal 30 from the microphone is shown.
Is subjected to FM modulation at the frequency of the 4.5 MHz oscillator 29 by the voice FM modulation circuit 28, and the voice synthesis circuit 2
6 and 27 are matched with the modulation frequency of the video signal 25. That is, the video signal 25 and the audio signal 30 are synthesized in conformity with the television broadcasting system in accordance with the frequency of the oscillator 23. Since the modulation of the video signal 25 is the same as that in the case of FIG. 3, the description thereof will be omitted.
Further, this modulation unit is the same whether it is inside or outside the video camera.

Therefore, in the surveillance camera system shown in FIG. 4, the monitor televisions 15a to 15c and 16 are provided.
Thus, it is possible to monitor the video content of each of the video cameras 12a to 12n as well as the audio content from the microphones 17a to 17n. Also, although not shown in FIG. 4, by connecting the VTR to the cable 10, the VT
Select the tuner of R as in the case of television,
The output of each video camera 12a-12n can be monitored and recorded.

In the above embodiment, the DC resistance value of the cable 10 is not taken into consideration, but if the cable length is very long, the DC resistance value of the cable 10 becomes so large that it cannot be ignored. In this case, as shown in FIG. 6, the power sources of the video cameras 12a to 12n may be connected from one place to a plurality of places according to the length of the cable 10.

FIG. 6 is a block diagram showing a surveillance camera system according to another embodiment of the present invention. In FIG. 6, video cameras 12a to 12n and a cable 10 are shown.
Etc. are the same as those described above, but assuming that the cable 10 is quite long, the cables 10 are 10a to 10b, the DC power supplies to the video cameras 12a to 12n are 18a to 18c, and the RF signals are Connect the coils 19a to 19c so that the DC power supplies 18a to 18c have high impedance.

The length of the cable 10 is 500 m, for example.
If the DC resistance value of the cable 10 is 0.1 Ω / m, then when the DC power supply 18a alone is used,
The video camera 12n 500m away from the power supply 18a has a resistance of 50Ω, and if the video camera consumes 500mA, the voltage of the video camera 12n has already dropped by 25V.
At the same time, useless power is consumed only to warm the cable. Therefore, the cable 10
By appropriately adding the DC power supplies 18b and 18c according to the length of each of the power supplies, the respective power supplies 18a, 18b and 18c supply power only to the nearby video cameras, and power loss and voltage drop are suppressed. It will be.

[0025]

As described above, according to the present invention, since a plurality of video cameras are connected by one cable, the wiring work can be easily performed when the video cameras are installed, added or changed. Moreover, it is possible to perform monitoring at a plurality of places, and further, by providing a microphone to each video camera, it is possible to perform audio without special wiring.

Further, by modulating the modulation system of the video signal output from the video camera according to the broadcasting system of the television, each video camera can be monitored by a general monitor television.

[Brief description of drawings]

FIG. 1 is a block diagram showing a surveillance camera system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a surveillance camera system according to another embodiment of the present invention.

FIG. 3 is a block diagram showing a modulation method of a video signal.

FIG. 4 is a block diagram showing a surveillance camera system according to another embodiment of the present invention.

FIG. 5 is a block diagram showing a modulation system for video and audio signals.

FIG. 6 is a block diagram showing a surveillance camera system according to still another embodiment of the present invention.

FIG. 7 is a block diagram showing a conventional surveillance camera system.

[Explanation of symbols]

10 cables 11a-11n mixer 12a-12n video camera 15a to 15c, 16 monitor TV 20 RF output 25 video signals

Claims (2)

[Claims] 1. A plurality of video cameras, a cable connected to the outputs of the plurality of video cameras, a mixer for coupling the cables with the respective video cameras, and output video from the respective video cameras. And a means for modulating a signal with a different frequency for each video camera. 2. The surveillance camera system according to claim 1, wherein an existing television receiver is connected to the cable by matching a modulation system of the output video signal with a broadcasting system of a television.