JPH05328187A - Television camera signal multiplex transmitter - Google Patents

Abstract

PURPOSE:To allow the user to simply switch the transmission of three R, G, B channels and the composite signal transmission by selecting a signal to be sent depending on the length and the purpose of a coaxial cable. CONSTITUTION:R,G,B video signals 1-3 obtained by the image pickup element of a camera head are encoded into a composite signal 5 in an encoder circuit 4 at the camera head side. The signals 5, 1 are sent to a transmission signal changeover circuit 6 and the switched G signal or the composite signal. is inputted to a multiplex transmission section 8 together with the signals 2, 3. When the signals 1-3 are outputted from the transmission section 8, they are inputted to an encoder circuit 9, and synthesized to be a composite output 11 via a changeover circuit 10. On the other hand, when the signal 5 is outputted from the multiplex transmission section 8 at the CCU side, a changeover circuit 12 is thrown to the position of the composite output and the composite output 11 is obtained through the changeover circuit 10. The circuits 6, 10, 12 implement changeover selection operation interlockingly via a CPU 7 with the information from a transmission system changeover selector 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a system for multiplex transmission of a television camera signal with a single coaxial cable.

[0002]

2. Description of the Related Art Conventionally, in a television camera system, transmission of a main line image signal, an audio signal, a control signal, and a power source is mutually performed between a camera head and a camera control unit (hereinafter abbreviated as CCU) that controls the camera head. There is one that is done with a single heavy coaxial cable (triaxial cable). In this case, each signal has a different carrier frequency and is frequency-multiplexed. In this case, in order to make the cable length between the camera head and the CCU as long as possible, the higher the carrier frequency, the more the attenuation amount due to the cable increases, so that the main line video signal and the like are arranged in the low frequency band.

FIG. 2 shows a frequency array of this transmission signal. The frequencies are allocated from 50 Hz / 60 Hz to 93.5 MHz for the power supply AC for the camera head. here,
Main line video signals are R, G and B signals of 34.7 MHz and 1 respectively.
It transmits at 6.6MHz and 52.5MHz frequencies, and CCU
On the side, the R, G, B signals are converted into a composite signal and output. Separately, R, G, B 3 channel signals are also output, and video processing such as chroma keying, R, G, B
Used for waveform observation and R, G, B monitor signals.

However, when the CCU and the CCU are separated from each other in a golf relay or baseball relay and the length of the triaxial cable is increased, the attenuation amount of the carrier wave of the B channel having a high frequency is increased and the S / N is deteriorated. Although the S / N of the R channel is not so deteriorated, the image quality of the composite signal is deteriorated. Also, R, G,
An encoder circuit for synthesizing B signals is provided on the camera head side, and if it is transmitted after being converted into a composite signal, only one channel transmission is required. Therefore, the triaxial cable length is 1 compared to the three channels of R, G, and B. .5 times to 2
Double extension is possible, but various video processing will not be possible.

[0005]

As described above, R, G,
The 3-channel transmission of B has various contradictory advantages and disadvantages that various kinds of image processing can be performed but a long transmission distance cannot be obtained, and long-distance transmission is possible in one-channel transmission of a composite signal but various kinds of image processing cannot be performed. In consideration of these advantages and disadvantages, the present invention allows the user to perform R, G, B3
The objective is to realize a camera system that can easily switch between channel transmission and composite 1-channel transmission or automatically according to the cable length.

[0006]

In order to achieve the above object, the present invention uses a single coaxial cable between a television camera head and a camera control unit to provide various signals such as video signals, audio signals and control signals. In a television camera signal multiplex transmission device for frequency multiplex transmission of
It is configured to have means for selecting and switching the signal transmitted through the transmission line according to the length of the coaxial cable, the purpose of use such as video processing, and transmitting.

[0007]

As a result, the user can easily switch between R, G, B three-channel transmission or composite transmission depending on the transmission cable length, image quality, and video processing status.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. 1 to 3 are R, G, B input signals from the image pickup device, 4
Is an encoder circuit on the camera head side, 5 is a composite signal output from the encoder circuit 4, 6 and 12 are switching circuits for switching the input / output of the multiplex transmission unit 8 between the G signal 1 and the composite signal, 13 Is a transmission system switching selector for instructing this switching selection, 7 is a CPU, 8 is a multiplex transmission section, 9 is an encoder circuit on the CCU side, 11 is a composite signal output, 10 is a circuit for switching the composite signal output, and 14 to 16 are R, G, B output signals.

This operation will be described below. The R, G, B video signals 1, 2 and 3 obtained by the image pickup device (not shown) of the camera head are supplied to the encoder circuit 4 on the camera head side.
Is input to and a composite signal 5 is produced. The composite signal 5 and the G signal 1 are input to the transmission signal switching circuit 6 on the camera head side. The G signal or composite signal switched here is input to the multiplex transmission section 8 on the camera head side together with the R signal 2 and the B signal 3. When G, R, B signals 1, 2, and 3 are output from the CCU-side multiplex transmission unit 8, they are input to the CCU-side encoder circuit 9, combined, and output as a composite output 11 through the switching circuit 10. It

On the other hand, when the composite signal 5 is output from the multiplex transmission unit 8 on the CCU side, the switching circuit 12 falls to the composite output side and is output as the composite output 11 through the switching circuit 10. The switching circuit 6 on the camera head side and the switching circuits 10 and 12 on the CCU side perform switching selection operations in cooperation with each other via the CPU 7 according to information from the transmission system switching selector 13 on the CCU side.

[0011]

According to the present invention, the signal format to be transmitted can be switched and selectively used according to the purpose of use, such as when the maximum transmission distance is required or when it is desired to process an image using R, G, B signals. The usability at the relay site can be greatly improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the overall configuration of the present invention.

FIG. 2 is a diagram showing a frequency array of transmission signals.

[Explanation of symbols]

 4,9 Encoder circuit 8 Multiplex transmission section 6,10,12 Signal switching circuit 7 CPU 13 Transmission method switching selector

Claims (1)

[Claims] 1. A television camera signal multiplex transmission apparatus for frequency-multiplexing various signals such as video signals, audio signals, and control signals between a television camera head and a camera control unit by a single coaxial cable. A television camera signal multiplex transmission device having means for selecting and switching a signal transmitted through a line according to the length of a coaxial cable, a purpose of use such as video processing, and transmitting the signal.