JPH0591381A - Signal transmission device - Google Patents

Abstract

PURPOSE:To easily transmit control data other than a video signal or the like with one transmission line by transferring the control data while taking the transmitted synchronizing signal as a reference without applying the external synchronization. CONSTITUTION:In applying the external synchronization to a television camera 2, a control circuit 26 selects and inputs a composite synchronizing signal SYNC 1 to be outputted from a synchronizing separator circuit 24 and outputs a reference signal for control data transmission while taking the synchronizing signal SYNC 1 as a reference. On the other hand, in applying no external synchronization to the television camera 2, the control circuit 26 takes in a composite synchronizing signal SYNC 2 to be outputted from a synchronizing separator circuit 28 and generates a reference signal for control data transmission while taking the composite synchronizing signal SYNC 2 as a reference. In short, the reference signal SYNC 2 is generated based on a video signal SV1 from a video device 12 when applying no external synchronization, the reference signal SYNC 2 and control data DC1 are transmitted, and the control data DC1 is fetched by the video device 12 based on the reference signal SYNC 2.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Field of Industrial Application Conventional Technology Problems to be Solved by the Invention Means for Solving the Problems (FIG. 2) Action (FIG. 2) Example (1) Configuration of Example (FIGS. 1 to 3) (2) Operation of Embodiment (3) Effect of Embodiment (4) Other Embodiment Effect of Invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device and can be applied to, for example, a surveillance television camera.

[0003]

2. Description of the Related Art Conventionally, a surveillance television camera operates in synchronization with, for example, a synchronization signal output from a central surveillance device.

Therefore, in this kind of surveillance television camera, the synchronizing signal and the video signal can be transmitted bidirectionally by using one coaxial cable by detecting the potential difference between both ends of the terminating resistor. There has been proposed (Japanese Patent Laid-Open No. 3-58535).

According to this method, it is possible to connect between the television camera and the monitoring device by installing only one coaxial cable, and the cable installation work can be simplified accordingly.

[0006]

By the way, in this type of surveillance television camera, it is necessary to transmit control data for panning, tilting, zooming, etc. of the television camera in addition to the synchronizing signal. Further, it is necessary to transmit the position information of the television camera to the monitoring device from the television camera side.

At this time, it is considered to be convenient if the coaxial data can be transmitted at the same time without using a separate cable for transmitting control data.

When transmitting data from the television camera to the monitoring device, the data can be transmitted with reference to the video signal sent from the television camera.
For example, by superimposing and transmitting data in the vertical blanking interval of the video signal, the transmitted data can be reproduced on the monitoring device side with reference to the video signal.

On the other hand, in the data transmitted from the monitoring device side, when the synchronization signal is transmitted from the monitoring device side, the data can be transmitted with reference to the synchronization signal. That is, in the same way as when transmitting by superimposing on the video signal, by superimposing and transmitting the data in the vertical blanking interval of the relevant synchronizing signal, in the television camera, the data transmitted on the basis of the relevant synchronizing signal is used. Can be played.

However, in this type of surveillance television camera, the synchronization signal may not be transmitted in some cases. In this case, on the monitoring device side, the only reference signal for transmitting the control signal is the video signal transmitted from the television camera.

Therefore, even if data is transmitted from the monitoring device side with reference to the video signal, the television camera side causes the delay time to change depending on the length of the coaxial cable. Can't play. Therefore, there is a problem that it is difficult to transmit the control data when the synchronization signal is not transmitted from the monitoring device side.

The present invention has been made in consideration of the above points, and an object thereof is to propose a signal transmission device capable of easily transmitting control data.

[0013]

In order to solve such a problem, according to the present invention, a signal transmission device 1 in which a video signal SV1 sent from a video device 12 is received by a control device 8 via a single transmission line 10. In, the control device 8 is separated by the video signal separation circuits 38, 42, 50 and 52 for separating the video signal SV2 transmitted via the transmission line 10 and the video signal separation circuits 38, 42, 50 and 52. Video signal SV
Reference signal generation circuits 26 and 28 that generate a reference signal (SYNC2) with reference to 2, and a reference signal (SYNC2).
At a predetermined timing based on the reference signal (SYNC
2) control data superimposing circuits 30 and 34 that superimpose predetermined control data DC1 on and output a control data superimposing signal, and a control data transmitting circuit 36 that transmits the control data superimposing signal to the video device 12 via the transmission path 10. And a video device 1
Reference numeral 2 denotes a video signal output circuit 92 that outputs the video signal SV1 to the transmission path, and signal separation circuits 62, 64, 66 and 6 that separate the control data superimposed signal transmitted via the transmission path 10.
8, reference signal separation circuits 80, 82 for separating the reference signal SYNC2 from the control data superimposed signals separated by the signal separation circuits 62, 64, 66, 68 and outputting a separation reference signal (SYNC3); Control data extraction circuits 68, 70 for extracting the control data DC1 from the control data superimposed signals separated by the signal separation circuits 62, 64, 66, 68 on the basis of (SYNC3) are provided.

[0014]

Even if the external synchronization is not applied, the reference signal SYNC2 is generated with the video signal SV1 coming from the video device 12 to be transmitted as a reference, and the reference signal SYNC2 and the control data with the reference signal SYNC2 as a reference. DC1 is transmitted, and the reference signal SYNC is sent to the video device 12.
If the control data DC1 is fetched on the basis of 2, the control data DC1 can be surely transmitted.

[0015]

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

(1) Configuration of the Embodiment In FIG. 1, reference numeral 1 denotes a monitoring system as a whole, and a video signal SV1 output from a television camera 2 is monitored by a monitor device 4. At this time, in the monitoring system 1, the synchronization signal EXT-SYNC generated by the synchronization signal generator 6 is received by the control device 8 as necessary, and the synchronization signal EXT-SYNC is received by the signal processing device 12 via the coaxial cable 10. , Thereby driving the television camera 2 in synchronization with the synchronization signal EXT-SYNC.

Further, the video signal SV1 output from the television camera 2 is transmitted to the control device 8 via the signal processing device 12, where the video signal SV2 is reproduced and output to the monitor device 4. As a result, in the monitoring system 1, the synchronizing signal EXT-SYNC and the video signal SV can be bidirectionally transmitted using the single coaxial cable 10.

At this time, the control device 8 superimposes predetermined control data on the synchronization signal and sends it to the coaxial cable 10, whereby the television camera 2 can be panned, tilted and zoomed. On the contrary, the signal processing device 12 superimposes the control data indicating the orientation of the television camera 2 on the video signal SV and transmits the control data, whereby the surveillance system 1 controls the television camera 2 to obtain the desired data. It is designed so that the subject of can be monitored.

That is, as shown in FIG. 2, in the control device 8, after the synchronizing signal EXT-SYNC is terminated by the terminating resistor 20, the synchronizing separation circuit 24 is provided via the capacitor 22.
In response to this, the composite synchronizing signal SYNC1 is generated.

When the television camera 2 is externally synchronized, the control circuit 26 selectively inputs the composite sync signal SYNC1 output from the sync separation circuit 24, and uses the sync signal SYNC1 as a reference to send a control data reference. Output a signal. On the other hand, when external synchronization is not applied to the television camera 2, the control circuit 26 causes the sync separation circuit 28
The composite synchronizing signal SYNC2 output from the device is taken in, and a reference signal for transmitting control data is generated based on the composite synchronizing signal SYNC2.

Further, the control circuit 26 controls the composite synchronizing signal SY.
A clock signal for fetching control data coming from the transmission object is generated based on NC2, and the clock signal is output to the central processing unit (CPU) 30.

The CPU 30 generates control data DC1 such as pan and tilt in response to the operation of a predetermined operator, and outputs the control data DC1 based on the reference signal of the control circuit 26.

That is, as shown in FIG. 3, the control circuit 26
The composite sync signal SYNC1 or SYNC2 selectively input by
, From 10 lines to 19 for odd fields
Line (Fig. 3 (A)), 273 for even fields
The control data DC1 is output from line 282 to line 282 (FIG. 3B). Further, the CPU 30 has a selection circuit 32.
When the external contact is applied to the television camera 2 by controlling the contact of the switch, the composite sync signal SYNC1 generated from the sync signal EXT-SYNC is selectively output to the adder circuit 34, whereby the composite sync signal SYNC1 receives control data. DC1 is superimposed.

On the other hand, when external synchronization is not applied to the television camera 2, the composite sync signal SYNC2 generated by the sync separation circuit 28 is selected and output to the adder circuit 34, whereby the composite sync signal SYNC2 is selected. The control data DC1 is superimposed. As a result, in the control device 8, the output signal of the adder circuit 34 is transferred to the amplifier circuit 36 and the resistor 3
8, when it is sent to the coaxial cable 10 via the condenser 40 in order to externally synchronize the television camera 2,
While the control data DC1 is transmitted after being superimposed on the composite sync signal SYNC1 generated from the sync signal EXT-SYNC, the composite sync signal generated by the sync separation circuit 28 when the television camera 2 is not externally synchronized. SYN
Control data DC1 is superimposed on C2 and transmitted.

The superposition separation circuit 42 separates the video signal SV2 transmitted through the coaxial cable 10 and then outputs the video signal SV2 to the monitor device 4 through the amplification circuit 44, the resistor 46 and the capacitor 48 in this order. Here, the video signal SV2 is
As disclosed in Japanese Patent Laid-Open No. 3-58535, a capacitor 50
And 52, the voltage across the resistor 38, which has the same resistance value as the characteristic impedance of the coaxial cable, is detected, so that the voltage is separated based on the potential difference between the terminal voltages.

That is, in the composite synchronizing signal sent from the control device 8, the terminal voltage on the side of the capacitor 50 is higher than the terminal voltage on the side of the capacitor 52, whereas in the video signal SV, the opposite is true. Capacitor 52
Since the terminal voltage on the side is higher than the terminal voltage on the side of the capacitor 50, the terminal voltage on both ends can be subtracted to separate the video signal SV. Thereby, in the monitoring system 1, the signal can be transmitted bidirectionally using one coaxial cable, and the image of the television camera 2 can be monitored through the monitor device 4. There is.

Further, the superposition separation circuit 42 detects 10 to 19 lines in the odd field and 273 to 282 lines in the even field based on the vertical synchronizing signal of the video signal SV2, and detects the horizontal line of the line. By opening and closing the gate based on the synchronization signal, the control data DC2 superimposed and transmitted on the video signal SV2 is captured. Further, the superposition separation circuit 42 outputs the fetched control data DC2 to the CPU 30, and thereby receives the control data DC2 transmitted from the signal processing device 12.

In this way, the control device 8 fetches the control data DC2 with reference to the video signal SV2, so that the signal processing device 12 simply superimposes the control data DC2 on the video signal SV2 at a predetermined timing. Thus, even when the length of the coaxial cable 10 changes, the control data DC2 can be reliably received on the control device 8 side. Further, by transmitting the control data DC2 based on the video signal SV2 sent from the signal processing device 12 side as described above, the control data DC2 can be reliably received regardless of the external synchronization of the television camera 2. can do.

The sync separation circuit 28 receives the video signal SV2 output from the superposition separation circuit 42 and separates the sync signal SYNC2 from the video signal SV2. Thus, in the control device 8, when the television camera 2 is externally synchronized, the synchronization signal SYNC1 is generated with the synchronization signal EXT-SYNC generated by the synchronization signal generator 6 as a reference.
And the control data DC1 is sent based on the sync signal SYNC1, the sync signal SYNC2 is sent based on the video signal SV2 coming from the transmission target when the television camera 2 is not externally synchronized.
And the control data DC1 is output based on the synchronization signal SYNC2.

As a result, in the control device 8, even when the external synchronization cannot be written to the television camera 2, the synchronization signal SYNC2 serving as the reference signal for sending the control data DC1 is generated.
Is transmitted to the signal processing device 12. As a result, the signal processing device 12 can detect the control data DC1 with or without external synchronization with reference to the synchronization signal coming from the control device 8.

That is, in the signal processing device 12, the output signal of the coaxial cable 10 is received by the terminating resistor 62 having the same resistance value as the characteristic impedance of the coaxial cable 10 through the capacitor 60, and the terminating end is received through the capacitors 64 and 66. The voltage across the resistor 62 is taken into the superposition separation circuit 68. Here, the superposition separation circuit 68 is the superposition separation circuit 42.
Using the same method as the above, the sync signals SYNC1 and SYNC2 transmitted from the control device 8 are separated.

Further, the superposition separation circuit 68 opens and closes the gate with reference to the synchronizing signals SYNC1 and SYNC2, so that 10 to 19 lines at an odd field,
In the even field, the control data DC1 superimposed on the 273 to 282 lines is taken in. Thus, by transmitting the synchronization signal regardless of the presence or absence of external synchronization and transmitting the control data DC1 with reference to the synchronization signal, the control data DC1 can be reliably transmitted in the monitoring system.

Thus, in the signal processing device 12, the superimposition separation circuit 68 outputs the fetched control data DC1 to the central processing unit 70, so that the television camera 2 can be panned, tilted, etc. as required. ing. When applying external synchronization to the television camera 2, the switch circuit 72 switches to the ON state, and the synchronization signal SYNC1 separated by the superposition separation circuit 68 is amplified by the amplification circuit 7.
4, the terminating resistor 76 and the capacitor 78 are sequentially output to the television camera 2.

As a result, the television camera 2 picks up an image of a subject with the synchronizing signal SYNC1 as a reference, and as a result, the video signal SV synchronized with the synchronizing signal SYNC1.
1 is generated.

The sync separation circuit 80 receives the sync signals SYNC1 and SYNC2 separated by the superposition separation circuit 68, and outputs the composite sync signal SYNC3 to the control circuit 82.
As a result, the control circuit 82 generates a clock signal for fetching the control data with reference to the synchronization signal coming from the transmission object, and outputs the clock signal to the central processing unit (CP).
U) Output to 70. Further, the control circuit 82 generates a reference signal for sending the control data DC2 based on the composite synchronization signal SYNC4 output from the synchronization separation circuit 84, and outputs the reference signal to the CPU 70.

That is, the sync separation circuit 84 receives the video signal SV1 output from the television camera 2 via the terminating resistor 86 and the capacitor 88, and generates the composite sync signal SYNC3 from the video signal SV1.
As a result, the control circuit 82 regardless of the presence or absence of external synchronization.
In the above, a reference signal for sending control data DC1 is generated with reference to the video signal SV1 sent from the signal processing device 12, and the control data DC2 is sent by the CPU 70 based on the reference signal.

The adder circuit 90 adds the video signal SV1 and the control data DC2 and then outputs the added signal to the terminating resistor 62 via the amplifier circuit 92, thereby superimposing the control data DC2 on the video signal SV1 and sending it. Thus, regardless of the presence or absence of external synchronization, the signal processing device 12 superimposes the control data DC2 on the basis of the video signal SV1 sent from the signal processing device 12, so that the control device 8 can control the video signal SV1. The control data DC2 can be easily received with the reference.

Therefore, the video signal and the synchronizing signal can be bidirectionally transmitted by using one transmission line, and the control data can be bidirectionally transmitted if necessary, and the monitoring system has a simple structure. The usability of 1 can be improved.

(2) Operation of the embodiment In the above configuration, when the television camera 2 is externally synchronized, the sync signal EXT-SYNC generated by the sync signal generator 6 is input to the sync separation circuit 24. After the composite synchronizing signal SYNC1 is generated at, the composite synchronizing signal SYNC1 is output to the coaxial cable 10 via the adding circuit 34. Further, the composite sync signal SYNC1 is
It is input to the control circuit 26, where the composite synchronization signal SY is input.
A reference signal for sending control data DC1 is generated with NC1 as a reference, and control data DC1 is sent from the CPU 30 with reference to the reference signal.

In this way, when the external synchronization is applied, the synchronization signal SYNC1 is sent to the signal processing device 12 and
Control data DC1 based on the synchronization signal SYNC1
Is sent. The synchronization signal SYNC1 and the control data DC1 are separated by the superposition separation circuit 68 and then output to the television camera 2 via the switch circuit 72, whereby the television camera 2 can be externally synchronized.

Further, the sync signal SYNC1 is output to the sync separation circuit 80, where the sync signal SYNC1 is output.
The synchronization signal SYNC3 is generated in synchronization with the control circuit 8
2 the control data D based on the synchronization signal SYNC3
A clock signal for C1 reception is generated. On the other hand, the control data DC1 is separated by the superposition separation circuit 68 and then output to the CPU 70, where the control circuit 82 is output.
It is received with reference to the reception clock signal generated in. As a result, the control data DC sent from the control device 8
1 can be received.

On the other hand, the video signal SV1 output from the television camera 2 is output to the coaxial cable 10 via the adding circuit 90. At this time, in the video signal SV1, the sync separation circuit 84 outputs the sync signal SYN.
After C4 is separated, a control data DC2 sending reference signal is generated with reference to the synchronization signal SYNC4, and the control data DC2 from the CPU 70 with reference to the reference signal.
Is sent. Accordingly, the signal processing device 12 superimposes the control data DC2 on the basis of the video signal SV1 and transmits the control data DC2.

The video signal SV1 is supplied to the superposition separation circuit 4
After being separated by 2, the monitor device 4 is passed through the amplifier circuit 44.
The video of the television camera 2 can be monitored by the monitoring device. Further, the video signal SV2 is supplied to the sync signal SYNC by the sync separation circuit 28.
2 is separated, and the control circuit 26 generates a clock signal for reading the control data DC2 on the basis of the synchronization signal SYNC2.

On the other hand, in the control data DC2, after being separated by the superposition separation circuit 42, the control data DC2 received by the CPU 30 on the basis of the read clock signal and sent from the signal processing device 12 to the control data DC2. Can be received. On the other hand, television camera 2
When the external synchronization is not applied to the video signal SV1, the video signal SV1 output from the television camera 2 is output to the coaxial cable 10 via the adding circuit 90 and the amplifying circuit 92. At this time, in the video signal SV1, the sync signal SYNC4 is separated by the sync separation circuit 84, and the sync signal SYNC is separated.
The control data DC2 is transmitted based on 4.

The video signal SV1 is supplied to the superposition separation circuit 4
After being separated by 2, the signal is output to the monitor device 4, and the synchronization separation circuit 28 further separates the synchronization signal SYNC2. As a result, when external synchronization is not applied, the synchronization signal SYN
While receiving control data DC2 based on C2,
The synchronization signal SYNC2 is sent to the coaxial cable 10 via the selection circuit 32.

Further, at this time, the control data DC1 is output to the coaxial cable 10 with reference to the synchronization signal SYNC2, and the signal processing device 12 detects the synchronization signal SYNC3 by the synchronization separation circuit 80. The control data DC1 can be received based on the synchronization signal SYNC3.

(3) Effects of the Embodiments According to the above configuration, when the external synchronization is not applied, the synchronization signal is generated with reference to the video signal SV1 coming from the television camera 2 side, and the synchronization signal is transmitted to the television. By sending the control data DC1 based on the synchronization signal as well as sending it to the camera 2, the control data DC1 can be reliably transmitted and received based on the synchronization signal even when external synchronization is not applied. it can.

(4) Other Embodiments In the above-described embodiments, the case where control data is assigned to the vertical blanking interval and transmitted is described, but the present invention is not limited to this, and the point is that the control is performed with a video signal. It can be widely applied to the case where data is superimposed and transmitted.

Further, in the above-described embodiment, the video signal output from the television camera 2 is monitored by the monitor device 4.
However, the present invention is not limited to this, and can be widely applied to a case where a video signal is transmitted by connecting to a camera control unit (CCU), for example.

Further, in the above-mentioned embodiment, the case of transmitting the control data for controlling the pan and tilt of the television camera 2 has been described, but the present invention is not limited to this.
For example, it can be widely applied to the case of transmitting security data relating to the monitoring system, and further to the case of transmitting various data other than the security data.

[0051]

As described above, according to the present invention, even when the external synchronization is not applied, the synchronization signal is transmitted and the control data is transmitted with the synchronization signal as a reference, so that the synchronization signal is used as a reference. Thus, it is possible to obtain the signal transmission device that can receive the control data by using the simple configuration and superimpose the control data to transmit the signal bidirectionally.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of a monitoring system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing its detailed configuration.

FIG. 3 is a signal waveform diagram for explaining the operation.

[Explanation of symbols]

1 ... Surveillance system, 2 ... Television camera, 4 ...
... monitor device, 6 ... synchronization signal generator, 8 ... control device, 10 ... coaxial cable, 12 ... signal processing device, 2
4, 28, 80, 84 ... Sync separation circuit, 26, 82 ...
... control circuit, 42, 68 ... superposition separation circuit.

Claims (1)

[Claims] 1. A signal transmission device in which a video signal transmitted from a video device is received by a control device via one transmission path, wherein the control device receives the video signal transmitted via the transmission path. A video signal separation circuit for separating, a reference signal generation circuit for generating a reference signal based on the video signal separated by the video signal separation circuit, and the reference signal at a predetermined timing based on the reference signal. A control data superimposing circuit for superimposing predetermined control data on the signal and outputting a control data superimposing signal; and a control data transmitting circuit for transmitting the control data superimposing signal to the video device via the transmission path, The video device includes a video signal output circuit that outputs the video signal to the transmission path, a signal separation circuit that separates the control data superimposed signal transmitted via the transmission path, and A reference signal separation circuit for separating the reference signal from the control data superimposed signal separated by the signal separation circuit and outputting a separation reference signal, and the above-mentioned reference signal separation circuit separated based on the separation reference signal. And a control data extraction circuit for extracting the control data from the control data superimposed signal.