JPH06284324A - Coaxial multiplex image pickup device - Google Patents

Abstract

PURPOSE:To allow an image pickup part to have a field discriminating function, and plural image pickup parts to output video signals whose horizontal scannings are matched each other. CONSTITUTION:A signal whose signal width is changed in an odd numbered field and an even numbered field is generated by a field-classified vertical drive signal generating circuit 12, and transmitted through a power source superimposing circuit 6, coaxial cable 3, video signal superimposing circuit 7, video signal processing circuit 9, vertical drive signal separator circuit 10 to a field discriminating circuit 11. The field discriminating circuit 11 discriminates the odd numbered field from the even numbered field, and an image pickup circuit 8 outputs the video signal whose horizontal scanning is matched.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a single coaxial transmission line,
The present invention relates to a coaxial multiplex imaging device that multiplex-transmits a power supply, a video signal, a vertical drive signal, and the like.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing the structure of a conventional coaxial multiplex imaging apparatus, and FIG. 4 is a diagram for explaining the operation of a conventional coaxial multiplex imaging system. In FIG.
Reference numeral 21 is a power supply unit, 22 is an image pickup unit, and the image pickup unit 22 and the power supply unit 21 are connected by a coaxial cable 3. The vertical signal generating circuit 24 generates a vertical synchronizing signal, and is connected to the video signal output circuit 5 and the power supply superimposing circuit 6. The power supply superimposing circuit 6 superimposes a power supply and a vertical drive signal. The video signal superimposing circuit 7 receives the power supply from the power supply unit 21 and the vertical drive signal and superimposes the video signal. The video signal processing circuit 9 and the imaging circuit 2
8 is connected. The image pickup circuit 28 is also connected to the vertical drive signal separation circuit 10 and the video signal processing circuit 9. The vertical drive signal separation circuit 10 extracts only the vertical drive signal from the video signal superposition circuit 7.
Then, the image pickup circuit 28 uses this vertical drive signal to generate a video signal. This video signal is superposed on another signal and a power source in the video signal superposing circuit 7 via the video signal processing circuit 9. Further, the power supply used in the image pickup circuit 28 is supplied from the video signal superimposing circuit 7.

Next, the operation of the above conventional example will be described.
4, (a) is a video signal in the vertical period, (b) is a vertical drive signal, (c) is a video signal on which the vertical drive signal is superimposed, and (d) is a video signal output from the power supply unit 21. is there. Further, in FIG. 3, the vertical drive signal (b) generated by the vertical signal generation circuit 24 of the power supply unit 21 is the power supply superposition circuit 6, the coaxial cable 3, the video signal superposition circuit 7, the video signal processing circuit 9, and the vertical drive signal separation. It is input to the image pickup circuit 28 through the circuit 10. The image pickup circuit 28 generates a horizontal synchronization signal obtained by dividing one field period into 262.5 based on the vertical drive signal, and generates a video signal (a) by horizontal and vertical scanning of the screen. The video signal (a) is input to the video signal processing circuit 9 in the form of a signal (c) synchronized with the vertical drive signal (b). The signal (c) is transmitted to the video signal superposition circuit 7, the coaxial cable 3, the power supply superposition circuit 6, and the video signal output circuit 5. In the video signal output circuit 5, a signal (d) obtained by cutting the vertical drive signal out of this signal (c).
To an external monitor TV receiver. It should be noted that the vertical signal generation circuit 24 is not only capable of independently generating a vertical drive signal, but in the case of using a plurality of coaxial multiplex imaging devices, a vertical drive signal generated by another power supply unit 21 is vertically synchronized. It is also possible to accept a signal and generate a vertical drive signal in synchronism therewith.

As described above, in the above-described conventional coaxial multiplex image pickup apparatus, the image pickup section 22 can output a video signal in synchronization with the vertical drive signal generated by the power source section 21.

[0005]

However, the above-mentioned conventional coaxial multiplex image pickup device does not have a field discriminating function because the vertical drive signal generated by the vertical signal generating circuit 24 has the same signal waveform in both the odd field and the even field. . In the interlaced scanning, one frame is composed of two fields. In the first field, horizontal scanning starts from the left end of the screen, whereas in the second field, it starts from the center of the screen.
Whether the first field or the second field of the image pickup circuit 28 is determined by the timing when the power is turned on, and when using a plurality of image pickup devices in a common monitor television receiver, horizontal scanning may differ by half a period. There is. As a result, when the video output of the image pickup circuit in a different field is input to the monitor television receiver by channel switching, there is a problem that the horizontal synchronization of the monitor television receiver is disturbed.

The present invention solves such a conventional problem, and an object of the present invention is to provide an excellent coaxial multiplex image pickup device in which the fields of the image pickup circuit are matched and the horizontal synchronization is not disturbed in a monitor television receiver. To do.

[0007]

In order to achieve this object, a coaxial multiplex image pickup device of the present invention comprises a vertical drive signal generating means for generating a vertical drive signal having a different signal width in an odd field and an even field. Depending on the power supply superimposing circuit that superimposes the power supply, the video signal, and the vertical drive signal on the coaxial transmission line, the vertical drive signal separation circuit that separates the vertical drive signal from the video signal, and the signal width of the vertical drive signal. And an image pickup circuit for generating the above-mentioned video signal by discriminating a field and adding a horizontal synchronizing signal.

[0008]

With this configuration, when the field-specific vertical drive signal generation circuit generates an odd or even field signal, the field discrimination circuit discriminates whether the field is the first field or the second field. It is possible to superimpose a uniform horizontal synchronization signal on the video signal, and the horizontal synchronization will not be disturbed even when the video signal of another imaging device is switched.

[0009]

FIG. 1 is a block diagram showing an embodiment of the present invention,
FIG. 2 is a waveform diagram showing the waveform of the vertical drive signal of the same embodiment.

In FIG. 1, the same reference numerals as those in FIG. 3 have the same names and functions, and a description thereof will be omitted. Reference numeral 1 is a power supply unit, and 2 is an imaging unit, which are connected to each other by a coaxial cable 3. The vertical signal generation circuit 4 generates a vertical signal, and is connected to the vertical drive signal generation circuit 12 for each field. The field-specific vertical drive signal generation circuit 12 generates vertical drive signals having different widths in odd fields and even fields, and is connected to the video signal output circuit 5 and the power supply superimposing circuit 6. The power supply unit 1 includes a vertical signal generation circuit 4, a video signal output circuit 5, a power supply superposition circuit 6, and a vertical drive signal generation circuit 12 for each field.
The field discriminating circuit 11 discriminates the field based on the pulse width of the vertical drive signal, and is connected to the vertical drive signal separation circuit 10 and the image pickup circuit 8. The image pickup circuit 8 is a circuit that outputs a video signal in synchronization with the vertical drive signal, and is connected to the video signal superposition circuit 7, the video signal processing circuit 9, and the field determination circuit 11. The image pickup unit 2 is composed of a video signal superposing circuit 7, an image pickup circuit 8, a video signal processing circuit 9, a vertical drive signal separating circuit 10 and a field discriminating circuit 11.

FIG. 2A shows the waveform of the vertical drive signal in the odd field, which has a width of t1. (B) is the waveform of the vertical drive signal in the even field, and the width is t2.
The relationship between t1 and t2 is t1 <t2.

Next, the operation of the above embodiment will be described with reference to FIG. The vertical signal generating circuit 4 generates a pulse which becomes a vertical synchronizing signal, and its output is inputted to the vertical drive signal generating circuit 12 for each field. The vertical drive signal generation circuit 12 for each field generates a vertical drive signal for each field as shown in FIG. 2 based on the vertical signal generated by the vertical signal generation circuit 4. The generated vertical drive signal is sent to the power supply superimposing circuit 6 and is sent to the image pickup unit 2 via the coaxial cable 3 together with the power supply. Of the power and signals superimposed on the coaxial cable 3, the power is separated from other signals by the video signal superimposing circuit 7 and sent to the imaging circuit 8. Signals other than the power supply are sent to the vertical drive signal separation circuit 10 via the video signal processing circuit 9. The vertical drive signal separation circuit 10 extracts only the vertical drive signal, and the extracted vertical drive signal is discriminated by the field discrimination circuit 11 as the first field or the second field. That is, when the width of the vertical drive signal is t1, it is an odd field, that is, the first field, and the width is t2.
In the case of, it is determined as the even field, that is, the second field. Then, the image pickup circuit 8 outputs a video signal by horizontal scanning whose timing is changed according to the result of the field discrimination. The image pickup circuit 8 generates a horizontal sync signal by dividing one field period into 262.5 based on the vertical drive signal, and starts horizontal scanning from the left end of the screen in the case of the first field and from the center of the screen in the case of the second field. To do. This video signal is superimposed on the power supply and the vertical drive signal in the video signal superposing circuit 7 via the video signal processing circuit 9. Then, this superimposed video signal is transmitted to the power supply unit 1 through the coaxial cable 3 together with other signals, passes through the power supply superposition circuit 6, and is then sent to the video signal output circuit 5. The video signal output circuit 5 cuts off the vertical drive signal using the vertical drive signal input from the vertical drive signal generation circuit 12 for each field, and outputs only the video signal to a monitor television receiver or the like.

As described above, since the image pickup circuit 8 distinguishes between the odd field and the even field to generate the video signal, the video signal output by the video signal output circuit 5 of the power supply unit 1 is generated by the horizontal scanning at the timing matching the field. Can be taken out as.

When a plurality of coaxial multiplex image pickup devices of this embodiment are used, a vertical drive signal is input from one power supply unit 1 to a field-specific vertical drive signal generation circuit 12 of another power supply unit 1 and input. The field-specific vertical drive signal generation circuit 12 outputs the same waveform in synchronization with the input vertical drive signal instead of the output signal of the vertical signal generation circuit 4.

[0015]

As is apparent from the above embodiment, the present invention provides vertical drive signal generating means for generating a vertical drive signal having a different signal width in an odd field and an even field, a power supply, a video signal and the vertical drive. A power supply superimposing circuit that superimposes a signal and transmits / receives it on a coaxial transmission line, a vertical drive signal separation circuit that separates the vertical drive signal from the video signal, and a field based on the signal width of the vertical drive signal to determine a horizontal synchronization signal. By providing an image pickup circuit for generating the above-mentioned image signal added, the image pickup section discriminates a field and a video signal is produced by horizontal scanning in accordance with the field. Therefore, even when a plurality of image pickup devices are connected, It is possible to realize an excellent coaxial multiplex imaging device that can eliminate the horizontal synchronization disturbance of the TV monitor due to the difference. It is intended.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a coaxial multiplex imaging device according to an embodiment of the present invention.

FIG. 2A is a waveform diagram of a vertical drive signal in an odd field of the device, and FIG. 2B is a waveform diagram of a vertical drive signal in an even field of the device.

FIG. 3 is a schematic block diagram of a conventional coaxial multiplex imaging device.

4A is a waveform diagram of a video signal generated by an image pickup circuit, FIG. 4B is a waveform diagram of a vertical drive signal, and FIG. 4C is a waveform diagram of a video signal on which a vertical drive signal is superimposed. Waveform diagram of video signal output from

[Explanation of symbols]

3 coaxial cable (coaxial transmission line) 6 power supply superimposing circuit 8 imaging circuit 10 vertical drive signal separation circuit 11 field discrimination circuit 12 vertical drive signal generation circuit for each field (vertical drive signal generation means)

Claims (1)

[Claims] 1. A vertical drive signal generating means for generating a vertical drive signal having a different signal width in an odd field and an even field, and a power supply for transmitting and receiving a power supply, a video signal and the vertical drive signal by a coaxial transmission line. A superimposing circuit, a vertical drive signal separation circuit that separates the vertical drive signal from the video signal, and an imaging circuit that determines a field based on the signal width of the vertical drive signal and generates the video signal to which a horizontal synchronization signal is added. Coaxial multiplex imaging device equipped.