JP4679539B2 - Adapter and camera - Google Patents

Description

  The present invention relates to an adapter and a camera used in a surveillance camera system.

  Conventionally, in a surveillance camera system, there is a one-cable system in which a surveillance camera and its drive unit are connected by a single coaxial cable (see, for example, Patent Documents 1 and 2).

  Such a one-cable system is configured such that a video signal from a camera is transmitted to a drive unit via a coaxial cable, and power is supplied from the drive unit to the camera via a coaxial cable. In this system, a video signal output from a camera and a power supply voltage supplied to the camera are superimposed and transmitted through a coaxial cable.

There is also a system configuration as shown in FIG. In this case, the drive unit 9 of the one-cable system and the camera 4 in which the video signal output terminal and the power terminal are separately provided are used, and the video signal line 6 and the power line 7 connected to the camera 4 are connected. The coaxial cable 2 is connected to one end of the coaxial cable 2 via the adapter 8 and the other end of the coaxial cable 2 is connected to the drive unit 9. Is transmitted.
JP 2000-22996 A JP 2002-300462 A

  In the above conventional one-cable system, a one-cable camera suitable for the drive unit must be used. For example, a general-purpose camera having a separate video signal output terminal and power supply terminal may be used. could not.

  Further, in the system shown in FIG. 3, the adapter 8 corresponding to the power supply system of the drive unit 9 must be used. The power supply system includes a constant voltage power supply system that supplies power to the camera 4 using a power supply circuit that outputs constant voltage, and a constant current power supply system that supplies power to the camera 4 using a power supply circuit that outputs constant current. When the drive unit 9 is a constant voltage power supply type device, the adapter 8 having a built-in impedance conversion circuit for the constant voltage power supply method must be used, and the drive unit 9 is a constant current power supply type device. In this case, the adapter 8 having a built-in impedance conversion circuit for the constant current power supply method must be used.

  In the one-cable system described above, it is necessary to use a camera with a built-in impedance conversion circuit corresponding to the drive unit power supply system.

  The present invention has been made to solve the above problems, and provides an adapter and a camera that can connect a camera to a drive unit and supply power to the camera regardless of the power supply system of the drive unit. It is an object. In addition, an adapter is provided that can connect a camera (camera that does not support the one-cable method) with a separate video signal output terminal and power supply terminal to the one-cable drive unit, regardless of the power supply method of the drive unit. The purpose is that. In addition, the video signal output terminal and power supply terminal are separately connected to the existing one-cable drive unit (hereinafter referred to as “one-cable multi-station drive unit”) that can connect multiple one-cable cameras. Cameras that do not support the one-cable system can be connected, and one single-unit drive unit for one-cable system can cover existing one-cable cameras and cameras that are not compatible with the one-cable system. It aims to provide an adapter that makes it possible.

In order to achieve the above object, the adapter of the present invention includes a voltage supply terminal for supplying a predetermined voltage to the camera, and a coaxial to which a constant voltage by a constant voltage power supply system or a constant current by a constant current power supply system is supplied at one end. A cable connection terminal connected to the other end of the cable, first and second impedance conversion circuits, and the cable connection terminal and the first impedance conversion circuit when the voltage of the cable connection terminal is equal to or higher than a predetermined value. And a connection switching circuit for electrically connecting the cable connection terminal and the second impedance conversion circuit when the voltage of the cable connection terminal is less than the predetermined value, and The output voltage of the impedance conversion circuit connected to the cable connection terminal by the connection switching circuit is input and converted to the predetermined voltage. A voltage conversion circuit to output to the serial voltage supply terminal are provided, wherein the first voltage is the voltage of the cable connection pin when said predetermined voltage to said one end of the coaxial cable is supplied, the said coaxial cable The predetermined value is smaller than the first voltage, and the second voltage is assumed to be larger than a second voltage that is a voltage of the cable connection terminal when the constant current is supplied to one end. It is determined to be larger than the voltage of.

  According to this configuration, the power supply system of the drive unit connected to one end of the coaxial cable is a power supply system that supplies a constant voltage or a power supply system that supplies a constant current. The first and second impedance conversion circuits corresponding to the drive unit are provided, and the connection is switched by the connection switching circuit so that the impedance conversion circuit corresponding to the drive unit power supply system functions. Therefore, regardless of the drive unit power supply system The camera can be connected to the drive unit to supply power to the camera.

  Also, a video signal input terminal for inputting a video signal from the camera, and the video signal input from the video signal input terminal is connected between the video signal input terminal and the cable connection terminal. It is good also as a structure provided with the connection circuit between terminals for guide | inducing to a cable connection terminal.

  According to this configuration, regardless of the power supply system of the drive unit, a camera having a separate video signal output terminal connected to the video signal input terminal and a power supply terminal connected to the voltage supply terminal (not compatible with the one-cable system). Compatible cameras) can be connected to a one-cable drive unit. In addition, a camera that is not compatible with the one-cable system can be connected to a multi-station drive unit for the one-cable system, so one existing multi-station drive unit for the one-cable system can be used for the existing one-cable system. It is possible to cover the cameras that are not compatible with the one cable system.

  The camera of the present invention incorporates the adapter described above.

  According to this configuration, the camera can be connected to the drive unit and power can be supplied to the camera regardless of the power supply system of the drive unit.

  The present invention has the configuration described above, and can provide an adapter and a camera that can connect a camera to the drive unit and supply power to the camera regardless of the power supply system of the drive unit. Play. In addition, regardless of the power supply system of the drive unit, it is possible to provide an adapter that can connect a camera having a video signal output terminal and a power supply terminal separately to a one-cable drive unit. In addition, cameras that are not compatible with the one-cable system can be connected to the drive unit of the one-cable system, and one existing multi-station drive unit for the one-cable system can be used. There is an effect that it is possible to provide an adapter that makes it possible to cover a camera and a camera that does not support the one-cable system.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of a surveillance camera system using an adapter according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of the adapter according to the embodiment of the present invention.

  In FIG. 1, a camera 1 is a surveillance camera compatible with the one cable system, and a camera 4 is a general-purpose surveillance camera not compatible with the one cable system.

  The camera 1 and the drive unit 3 are well-known devices used in a one-cable system in which each other is connected by a single coaxial cable 2. In this one-cable system, a video signal from the camera 1 is transmitted to the drive unit 3 via the coaxial cable 2, and power is supplied from the drive unit 3 to the camera 1 via the coaxial cable 2. Yes.

  The camera 1 extracts the power supply voltage from the coaxial cable 2 and sends a video signal to the coaxial cable 2. The drive unit 3 extracts the video signal transmitted through the coaxial cable 2 and displays the extracted video signal on a monitor display (not shown). And the like, and a constant voltage or a constant current for camera power supply is supplied to the coaxial cable 2. Therefore, the video signal output from the camera and the power supply voltage supplied to the camera are superimposed and transmitted through the coaxial cable 2.

  Further, the drive unit 3 is provided with a plurality of terminals for connecting the coaxial cable 2 to connect a plurality of cameras, and the video signals transmitted from the plurality of cameras are respectively displayed on separate monitor displays (not shown). A terminal is provided for output to the terminal. The drive unit 3 is supplied with, for example, AC 100 V as its drive power, and has a built-in power supply circuit that generates DC to be supplied from the AC 100 V to the camera 1 and outputs it to the coaxial cable 2. If this power supply circuit is a constant voltage power supply system, it is a constant voltage generation circuit that generates and outputs a constant DC voltage, and if it is a constant current power supply system, it generates a constant DC current and outputs it. It is. Inside the camera 1, an impedance conversion circuit corresponding to the power supply system of the drive unit 3 is incorporated. That is, when the power supply circuit in the drive unit 3 is a constant voltage generation circuit (when the drive unit 3 is a constant voltage power supply type device), the constant voltage power supply type impedance conversion circuit is built in the camera 1 and the drive unit 3 is a constant current generating circuit (when the drive unit 3 is a constant current power supply type device), a constant current power supply type impedance conversion circuit is built in the camera 1. Thus, the camera 1 is used exclusively for the drive unit 3.

  On the other hand, the camera 4 is not a one-cable camera, but a general-purpose camera in which a video signal output terminal 41 to which the video signal line 6 is connected and a power terminal 42 to which the power line 7 is connected are provided separately. It is. The video signal line 6 and the power supply line 7 can be connected to the coaxial cable 2 via the adapter 5 of the present embodiment.

  As shown in FIG. 2, the adapter 5 has a video signal input terminal 11 to which the video signal line 6 is connected, a voltage supply terminal 12 to which the power line 7 is connected, and a cable connection terminal to which the coaxial cable 2 is connected. 13 is provided.

  The video signal input terminal 11 is connected to the cable connection terminal 13 via, for example, a DC blocking inter-terminal connection circuit 20 in which a DC blocking capacitor and a resistor are connected in series.

  A constant voltage power supply system impedance conversion circuit 17 and a constant current power supply system impedance conversion circuit 18 are connected to the cable connection terminal 13 via a switching relay 16. The constant voltage power supply type impedance conversion circuit 17 is configured using, for example, a transistor, and when the drive unit 3 is a constant voltage power supply type device, the constant voltage power supply type impedance conversion circuit built in the known camera 1 is used. Is the same. Further, the constant current power supply system impedance conversion circuit 18 is configured by using, for example, a transistor or the like, and when the drive unit 3 is a constant current power supply system device, the constant current power supply system built in the known camera 1 is used. This is the same as the impedance conversion circuit.

  The DC / DC conversion circuit 19 is connected to the output side of the two impedance conversion circuits 17 and 18 via the switching relay 15, and the voltage supply terminal 12 is connected to the output terminal of the DC / DC conversion circuit 19. Yes. Further, for example, a relay control circuit 14 that controls the switching relays 15 and 16 based on the voltage of the cable connection terminal 13 is provided.

  The drive unit 3 is connected to the coaxial cable 2 because the voltage for the camera power sent from the drive unit 3 to the coaxial cable 2 is different between the case where the drive unit 3 is a constant voltage power supply type device and the case where the drive unit 3 is a constant current power supply type device. The voltage of the cable connection terminal 13 is also different. For example, in the case of the constant voltage power supply system, a constant voltage of, for example, DC 20 V is supplied from the drive unit 3 to the coaxial cable 2, and the voltage of the cable connection terminal 13 is V1 (for example, due to transmission loss in the coaxial cable 2 having a length of several hundred meters. DC tens of volts). In the case of the constant current power supply system, a constant current of, for example, 200 mA (voltage is several tens of volts DC) is supplied from the drive unit 3 to the coaxial cable 2, and the voltage at the cable connection terminal 13 is V2 (due to transmission loss in the coaxial cable 2. <V1). Thus, in the case of the constant voltage power supply method, the voltage of the cable connection terminal 13 is V1, and in the case of the constant current power supply method, if the voltage of the cable connection terminal 13 is V2 (<V1), the value of the threshold value Vt. V2 <Vt <V1, and in the relay control circuit 14, if the voltage of the cable connection terminal 13 is equal to or higher than the threshold value Vt, a constant voltage is applied between the cable connection terminal 13 and the DC / DC conversion circuit 19. The switching relays 15 and 16 are controlled so that the power system impedance conversion circuit 17 is connected and the constant current power system impedance conversion circuit 18 is disconnected, and if it is less than the threshold value Vt, the constant current power system impedance conversion is performed. It is configured to control the switching relays 15 and 16 so that the circuit 18 is connected and the constant voltage power supply system impedance conversion circuit 17 is disconnected. That. The relay control circuit 14 is configured using, for example, a comparator that compares the voltage of the cable connection terminal 13 and the threshold value Vt, and a battery may be used as the power source of the comparator.

  The operation of the surveillance camera system configured as described above will be described.

  The camera 4 is driven by being supplied with a constant voltage (for example, DC 12 V) from the power line 7. The video signal output from the camera 4 is a high-frequency signal, and is input from the video signal input terminal 11 to the adapter 5 via the video signal line 6. This video signal is output to the cable connection terminal 13 via the inter-terminal connection circuit 20.

  On the other hand, the power supply voltage for the camera is supplied from the drive unit 3 to the cable connection terminal 13 through the coaxial cable 2. In the relay control circuit 14, as described above, for example, the switching relays 15 and 16 are controlled based on the voltage of the cable connection terminal 13, and one impedance conversion circuit (17 or 18) corresponding to the power supply system of the drive unit 3 is connected. The The output voltage of the impedance conversion circuit (17 or 18) is input to the DC / DC conversion circuit 19, converted into a constant voltage (for example, DC12V) by the DC / DC conversion circuit 19, and output from the voltage supply terminal 12. It is supplied to the camera 4 via the line 7.

  The operation between the camera 1 and the drive unit 3 is the same as the operation in the conventional one-cable system, and the description thereof is omitted.

  The adapter 5 of the present embodiment is provided with two impedance conversion circuits 17 and 18 corresponding to the two power supply methods, respectively, so that the impedance conversion circuit corresponding to the power supply method of the drive unit 3 to be used functions. Therefore, regardless of the power supply system of the drive unit 3, the general-purpose camera 4 having the video signal output terminal 41 and the power supply terminal 42 separately can be connected to the one-cable drive unit 3.

  In addition, since the camera 4 that does not support the one-cable method can be connected to the one-cable-system drive unit such as the drive unit 3 of the present embodiment via the adapter 5, the existing one-cable method It is possible to cover the existing one-cable camera 1 and the non-cable camera 4 with a single multi-station drive unit.

  Further, if the camera 4 is configured to incorporate the adapter 5 (a circuit having a function equivalent to that of the adapter 5), the camera and the drive unit 3 can be connected only by the coaxial cable 2.

  In addition, when the drive unit 3 is a drive unit that does not support the one-cable method, that is, a drive unit in which a video signal cable and a camera power cable are connected to different terminals (hereinafter referred to as “drive unit A”). The adapter 5 is an adapter that does not include the video signal input terminal 11 and the inter-terminal connection circuit 20 (hereinafter referred to as “adapter A”), and the cable connection terminal 13 of the adapter A is used for the camera power supply. The camera 4 can be connected to the drive unit A regardless of the power supply system of the drive unit A by connecting to the cable and connecting the voltage supply terminal 12 to the power line 7 connected to the camera 4. In this case, the other end of the video signal cable having one end connected to the drive unit A is connected to the video signal output terminal 41 of the camera 4. In addition, if the camera 4 is configured so that the adapter A (a circuit having a function equivalent to that of the adapter A) is built in, the camera and the drive unit A can be connected only by the coaxial cable 2 to supply power to the camera. Yes.

  In addition, the camera 1 corresponding to the one-cable system includes two impedance conversion circuits 17 and 18, a switching relay 15 and 16, and a relay control circuit 14 instead of the impedance conversion circuit built in the camera 1. The drive unit 3 can be used regardless of whether it is a constant voltage power supply apparatus or a constant current power supply apparatus.

  INDUSTRIAL APPLICABILITY The present invention is useful as an adapter for connecting a camera having a video signal output terminal and a power supply terminal to a one-cable drive unit in a surveillance camera system.

It is a block diagram which shows the structure of the surveillance camera system using the adapter of embodiment of this invention. It is a block diagram which shows the structure of the adapter of embodiment of this invention. It is a block diagram which shows an example of a structure of the conventional surveillance camera system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera 2 Coaxial cable 3 Drive unit 4 Camera 5 Adapter 6 Video signal line 7 Power supply line 11 Video signal input terminal 12 Voltage supply terminal 13 Cable connection terminal 14 Relay control circuit 15,16 Switching relay 17 Impedance conversion circuit 18 for constant voltage power supply systems Impedance conversion circuit 19 for constant current power supply system DC / DC conversion circuit 20 Connection circuit between terminals

Claims (3)

A voltage supply terminal for supplying a predetermined voltage to the camera;
A cable connection terminal connected to the other end of the coaxial cable to which a constant voltage by a constant voltage power supply system or a constant current by a constant current power supply system is supplied at one end;
First and second impedance conversion circuits;
When the voltage of the cable connection terminal is equal to or higher than a predetermined value, the cable connection terminal and the first impedance conversion circuit are electrically connected, and when the voltage of the cable connection terminal is lower than the predetermined value, A connection switching circuit for electrically connecting a cable connection terminal and the second impedance conversion circuit;
A voltage conversion circuit that inputs an output voltage of the impedance conversion circuit connected to the cable connection terminal by the connection switching circuit, converts the output voltage to the predetermined voltage, and outputs the voltage to the voltage supply terminal ;
The first voltage which is the voltage of the cable connection terminal when the constant voltage is supplied to the one end of the coaxial cable is the cable connection terminal when the constant current is supplied to the one end of the coaxial cable. The adapter is determined so that the predetermined value is smaller than the first voltage and larger than the second voltage on the assumption that the second voltage is greater than the second voltage . A video signal input terminal for inputting a video signal from the camera;
2. An inter-terminal connection circuit connected between the video signal input terminal and the cable connection terminal and for guiding the video signal input from the video signal input terminal to the cable connection terminal. Adapter described in . A camera incorporating the adapter according to claim 1 .

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