JPH07202929A - AV network system - Google Patents

Abstract

(57) [Summary] [Purpose] It is an object to provide an AV network system that can communicate between small-scale networks and can realize a large-scale network as a whole. In an AV network in which an AV network control device 105 controls a coupling device 104 to divide it into a plurality of groups 1 and 2 of a small-scale network, video and audio signals are transmitted between communication terminal devices 112a and 122b across the groups. When transmitting and receiving, the AV network control device 105 grasps the use status of the frequency in each group via the data network 103, and determines the frequency that can be used in each group to communicate with. The coupling device 104 converts the frequency transmitted by the communication terminal device of one of the plurality of groups 1 and 2 into a frequency usable by the other group, and the communication terminal device of the other group receives the frequency. To do.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the simultaneous transmission / reception of video / audio information between a plurality of communication terminal devices via a transmission line.
It relates to a V network system.

[0002]

2. Description of the Related Art A conventional AV network system is designed to enable communication between a plurality of communication terminal devices at the same time.
The frequency of the RF band, which is a communication band, is divided, each frequency is assigned to each communication terminal device, and each frequency is RF.
The signals are multiplexed on the band, and this signal is transmitted using a transmission line such as a coaxial cable.

In this way, the video / audio signals corresponding to the video / audio information are transmitted and received in real time between a plurality of communication terminal devices for communication. FIG. 3 is a configuration diagram of a conventional AV network system, which includes an AV communication cable 301 and a communication terminal device 30 having an AV communication function.
2a, 302b, a data network 303, A
V network communication frequency usage management,
The AV network control device 304 is configured to notify each terminal device of frequency allocation information. FIG. 4 is an example of frequency division of the communication band.

The operation of the AV network system having such components will be described. When performing communication between the terminal device 302a having the AV communication function and the same terminal device 302b, the terminal device 302a performs various procedures for communication with the control device of 304 through the network of 303, and the control device 304 is the terminal device 302
The input / output frequency is allocated so that a and the terminal device 302b can communicate with each other, and is notified to each of the terminal devices 302a and 302b through the network 303. Each terminal device 30
2a and 302b can transmit and receive video / audio information at the assigned frequency via the AV communication cable 301, and can communicate with each other.

[0005]

However, in such a conventional AV network system, the number of allocated frequencies in the RF band is finite, and the number of communication terminal devices that can be operated simultaneously is naturally limited. In this system, as shown in FIG. 4, the maximum number of used channels (channels) is determined, and according to the division example of FIG.
Only 0 terminal devices (= 30 calls) can communicate at the same time. For this reason, there was a problem that the network scale was limited and the operation was small.

The present invention aims to provide an AV network system capable of communicating across systems with a small network scale and operating as a large-scale system as a whole despite the limited number of allocated frequencies. To aim.

[0007]

In order to achieve the above object, the AV network system of the present invention communicates between communication terminal devices via a coaxial cable at a frequency multiplexed on an RF band to transmit a video image. AV that sends and receives audio signals
In a network system, a coupling device having means for dividing an AV network into a plurality of groups, and modulation / demodulation means for converting a frequency used in one of the groups into a usable frequency in the other group. A connection that grasps the frequency usage status in each group via a data network, determines the frequencies that can be used in each group to communicate, and controls the coupling device via the data network. And a device control means.

[0008]

With the above arrangement, the coupling device control means controls the coupling device to transmit and receive video and audio signals between communication terminal devices across groups in an AV network divided into a plurality of small-scale networks. In this case, the coupling device control means grasps the use status of the frequency in each group via the data network and determines the frequency that can be used in each group to communicate with,
The coupling device converts the frequency transmitted by the communication terminal device of one of the plurality of groups into a frequency that can be used by the other group, and the communication terminal device of the other group receives the frequency.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a block diagram of an AV network system according to the present embodiment, in which AV communication cables 111 and 121 are grouped, and communication terminal devices 112a, 112b, 122a and 122b having an AV communication function,
A data network 103, an AV network group coupling device 104 having a modulation / demodulation function, and each A
V network group communication frequency usage management and each terminal device 112a, 112b, 122a, 1
22b and the AV network control device 105 as a coupling device control means for controlling the coupling device 104 between the AV network groups.

The operation of the AV network system having such components will be described below. The AV communication cable 301 of the conventional system shown in FIG. 3 is divided into groups by means for dividing the AV network of the coupling device 104 into a plurality of groups, and the AV communication cable 111 and the AV communication cable 121 of each group are respectively divided. By using the entire communication band and enabling communication across groups, the number of terminal devices that can communicate at the same time is several times as large as that in the conventional system (60 terminal devices). Dependence).

Since the communication method within each group is exactly the same as that of the conventional system, only the modulation / demodulation means for performing communication between groups will be described. When communication is performed between the terminal device 112a and the terminal device 122b, the terminal device 112a performs a communication procedure with the control device 105 through the data network 103.
Since the terminal device 122b of the communication partner is not the same group, the control device 105 controls the coupling device 104 between the groups of the respective AV networks. For example, the channel that the terminal device 112a transmits is ch1a, the channel that the terminal device 112a receives is ch2a, and the terminal device 122b.
Ch1b and ch2b for transmitting and receiving
Ch1 transmitted from the terminal device 112a when
a is modulated by the modulation / demodulation means of the coupling device 104.
It is demodulated into ch2b and received by the terminal device 122b. Similarly, ch1b is modulated and demodulated to ch2a, so that communication between the terminal device 112a and the terminal device 122b becomes possible.

FIG. 2 is a functional block diagram of the AV network group coupling device 104 of this embodiment. Here, the operation of the coupling device 104 will be described with reference to the functional configuration diagram of FIG. 2. The frequency adjusting function instructed by the control device 105 is different from the arbitrary demodulation function on the group 1 side in the group 1
In order to demodulate the frequency of ch1a (the transmission ch from the terminal device in the group 1) of the AV network, the corresponding modulation function on the side of the group 2
It is adjusted so that it can be modulated to the frequency of ch2b (reception ch of the terminal device on the group 2 side). Similarly, ch of group 2
1b (the transmission channel of the terminal device on the group 2 side) is adjusted for the demodulation function and the corresponding modulation function,
Modulation / demodulation is performed on a (reception ch of the terminal device on the group 1 side). With the above adjustment, the communication terminal device 1 of the group 1
Communication is possible between 12a and the communication terminal device 122b of group 2.

By the above operation, it is possible to communicate between systems with a small network scale, despite the limited number of allocated frequencies, and to operate as a large-scale system as a whole.

In this embodiment, the control in each AV network group 1 and 2, the frequency adjustment between the groups 1 and 2 and the control of the coupling device 104 are all performed by one control device 105. It is also possible to have a control device for each AV network group 1, 2 in consideration of processing capacity, response time, etc., and to prepare one overall control device for performing frequency adjustment between the groups 1, 2.

[0015]

As described above, according to the present invention, in the AV network, when the video and audio signals are transmitted and received between the communication terminal devices across the groups, the coupling device control means operates within each group. The frequency usage status is grasped via the data network, the frequencies that can be used in each group to be communicated are determined, and by the coupling device, the communication terminal device of one of the plurality of groups transmits. The frequency can be converted into a frequency usable by the other group, and this can be received by the communication terminal device of the other group.

Therefore, the entire multiplexed frequency can be used for each group and communication can be performed between the groups. As a result, despite the finite number of frequency allocations,
Communication is possible across systems with a small network scale, and it can be operated as a large-scale system as a whole.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an AV network system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a coupling device according to the same embodiment.

FIG. 3 is a block diagram of a conventional AV network system.

FIG. 4 is an explanatory diagram of frequency division of the AV network system.

[Explanation of symbols]

 104 coupling device 105 AV network control device

Claims (1)

[Claims] 1. A means for dividing an AV network into a plurality of groups in an AV network system for transmitting and receiving a video / audio signal by communicating between communication terminal devices via a coaxial cable with a frequency multiplexed on an RF band. And a combination device having a modulation / demodulation means for converting a frequency used in one of the groups into a frequency usable in the other group, and a data network for the frequency usage status in each group. And a coupling device control means for controlling the coupling device via the data network by determining the frequency that can be used in each group to communicate with.
Network system.