JPH03280738A - Two-way communication equipment - Google Patents

Abstract

PURPOSE:To simplify the constitution of a terminal equipment by employing a transmission system suitable for coping with the difference from the quantity of information in existence in incoming information and outgoing information between 1st and 2nd terminal equipments. CONSTITUTION:When a feeding circuit 23 of a 2nd terminal equipment 2 is started by an interphone, a camera 4 sends a video signal to a picture processing circuit 5, where the signal is digitally converted. One frame of a picture is sent to the terminal equipment 2 by the base band transmission system for one burst period by a transmission frame constitution section 6. On the other hand, under the control of a 2nd system control circuit 22, a control signal output circuit 18 of the terminal equipment 2 sends the control signal in terms of pulse number of clock pulses adopted for the base band transmission to the 1st terminal equipment 1. Thus, the constitution of the terminal equipments is simplified by adopting the transmission system suitable for coping with the difference from the quantity of information in which the quantity of outgoing information is less than that of the incoming information.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial application field The present invention is directed to a two-way four-way communication system that can be used for two-way communication such as a doorbell.
The present invention relates to a communication device, and is a two-way communication device suitable for handling bidirectional information of a type in which the amount of uplink information is sufficiently larger than the amount of downlink information.

(b) Conventional technology Doorpon has a first terminal including a video camera installed at the front door, and a second terminal including a monitor that displays images taken by the video camera indoors. are connected by a transmission line that allows two-way communication,
It is possible to conduct an I':1 conversation between a visitor at the front door and a person indoors while observing the visitor's behavior on the indoor monitor (Sanyo Electric Technical Report Vol. 13, No. 3). ``Digital TV Door Bonn Stem'' described on page 71
).

This document is marked t7. The present invention shows that the door phone shown in the figure is capable of transmitting control signals for controlling the zoom of the camera and the attitude of the pan/tilt table from the second terminal to the first terminal over the transmission line. There is. In addition, since the necessary control information is limited, the company uses a simple method of sending and receiving two sets of data between both terminals in order to perform full-scale time-division bidirectional transmission. The specific structure of the simple scheme is not shown.

(C) Problems to be Solved by the Invention The present invention provides for transmitting and receiving downlink information whose amount of information is sufficiently small compared to the uplink information from the first terminal to the second terminal. The purpose of the present invention is to simplify the configuration means necessary for this purpose, and to provide a two-way communication device that can easily and stably transmit downlink information.

(d) Means for solving the problems The present invention adopts a base-node transmission method for digital signals to transmit uplink information from a first terminal to a second terminal, and In order to transmit downlink information from a second terminal to a first terminal, the downlink information (control signal) is transmitted using the clock pulses used for this baseband transmission or the number of clock pulses related to it. Adopt a method of expressing and transmitting information. (In order to prevent malfunctions due to missing pulses or increases in pulses due to noise, etc., a stepwise number of pulses is assigned to each control item. For example, if a specific number of pulses is If assigned, even if you count the number of pulses within the allowable range after +iii of the assigned number of pulses, it will be -1-
The configuration is such that it is recognized as a specified control item.

(e) Function: As mentioned above, the present invention employs transmission methods suitable for different amounts of information, so the configuration of each terminal can be simplified. 4. Bird information with a small amount of information is
By allocating the number of pulses corresponding to each of the plurality of control items in stages 1, the first receiving circuit of the first terminal that receives the pulses can give a convergence to the count number regarding the meaning of each control item. Even if there is an increase or decrease in the pulse within the permissible range (that is, a variation within the permissible range) with respect to the assigned pulse, the control item corresponding to the assigned pulse can be accurately recognized and recognized.

(F) Embodiment The two-way communication device of the present invention will be described with reference to a door-pong embodiment. FIG. 1 is a block diagram of the door phone according to the present embodiment. FIG. 2 is a diagram showing the time chart 1-(1 cycle) of the transmission signal used for this door-pocket.

In FIG. 1, 1 is a first terminal, 2 is a second terminal, and 3 is a transmission path.

The first terminal 1 includes a video camera 4 and an image processing circuit 5 that digitally embeds images taken by the video camera.
a transmission frame configuration circuit G that forms a transmission signal for baseband transmission of the digital signal from the image processing circuit; a first switch 7 that selects supply of the transmission signal to the j2 transmission line; a first receiving circuit 8 that receives a control signal from the second terminal via the transmission path and the first switch; and a first receiving circuit 8 that is driven by the output of the first receiving circuit.
The video camera includes a control means 9 for controlling the state of the R video camera, and a first system control section 10.

The video camera 4 uses, for example, a solid-state imaging device such as a CCD, captures the image of a visitor located in front of the doorbell, and outputs a video signal to its output terminal. The content of the video signal captured and output by the video camera 4 is configured to be controlled by the control means 9 based on a command from the second terminal (described later).

Each component of the first terminal including this video camera is
The power supply circuit 11 receives power from the power supply included in the second terminal via the transmission line 3 and is activated.

The image processing circuit 5 includes a video processing circuit 12 that configures a video signal from the video camera 4 into a standard television signal (for example, an NTSC signal), and an A/D converter 13 that converts this television signal into a digital signal. and an encoding circuit 1 that encodes this digital signal into a planar predictive code.
4, and a frame memory 15 for storing one frame of encoded data. This memory 15 stores appropriately thinned and compressed image data, and is configured so that new images are updated and stored in this memory at appropriate intervals. Two frame memories may be prepared and storage and reading may be performed alternately.

The transmission frame configuration circuit 6 is connected to the first system control circuit 10
Image data (
digital signals) as shown in Figure 2 A,
The transmission signal therein is repeatedly transmitted every burst period B. This burst period B includes a first half B1 allocated for transmitting uplink information and a second half B2 which is an empty section without a transmission signal. The second half B2 includes a period B3 in which downlink information from the second terminal 2 is received via the transmission path 3. In the example, the period B is 17715 seconds, and the period B2 is approximately 3.2 msec. Also, the first half B1
includes image data (digital signal) D from the image processing circuit 5 and a synchronization signal S of the system preceding it.

This transmission frame configuration circuit 6 is configured to transmit the synchronization signal S and the image data D in a baseband manner.

The clock used for this transmission is selected so that a signal can be transmitted through the transmission line 3 at a transmission rate of 1.79 Mt/sec. Note that the image data D includes not only pure image data but also various data for storing this image data, but a description thereof will be omitted.

The first switch 7 connects the transmission path 3 to the transmission frame configuration circuit 6.
Or selectively connected to the first receiving circuit 8,
This connection is controlled by the first system control unit 10. That is, the first system control unit IO controls the first switch 7 to connect the transmission frame configuration circuit 6 of the first terminal and the transmission line 3 during period B1 of each burst period, Also, during period B2 of each burst period, the first switch 7 is controlled to connect the first receiving circuit 8 of the first terminal and the transmission line 3. Note that this first switch 7 is connected to the transmission line 3.
and the transmission frame configuration circuit 6, and when the system is started up, it is configured so that upstream information can be transmitted from the first terminal to the second terminal. ing.

The first receiving circuit 8 receives a control signal from the second terminal via the transmission line 3 and the first switching device 7. and,
The content of the received control signal is identified and an output signal matching the content is supplied to the control means 9. This first receiving circuit 8 determines that the received control signal (clock pulse) is within a permissible range (in the embodiment, (accepting an increase or decrease of ±2 pulses), a correct control signal is transmitted to the control means.

The control means 9 receives the output signal from the first receiving circuit 8 and controls the video camera 4 according to the instructions of the output signal. FIG. 3 illustrates control items and control signals (number of pulses) assigned to the control items for controlling the video camera 4 by the control means 9. For example, when the first receiving circuit 8 counts 15±2 pulses as a control signal, it is determined that the control item is to tilt the video camera 4 upward, and the control means 9 controls the video camera in that manner. do. Note that this control means increases the amount of change (for example, the amount of tilt) of the video camera in proportion to the number of times the control signal is received every integer multiple of the burst period.

The first system control unit 10 controls the first switching device 7 as described above.
In order to not only control the image processing circuit 5, the transmission frame configuration section 6, and the first reception circuit 8, but also to determine the operation timings of the image processing circuit 5, the transmission frame configuration section 6, and the first reception circuit 8, a timing signal is sent to each circuit.
It is configured to give 4.

On the other hand, the second terminal 2 has a screen 1G for displaying the image, and an input stage 1 for instructing the status of the video camera.
7, an output circuit 18 that receives an instruction from the input means, determines the number of pulses to be output based on the instruction, and outputs a control signal, and supplies the control signal from this output circuit to the transmission path. a second receiving circuit 20 that receives the transmission signal from the first terminal via the transmission path and the second switching gain, and a second receiving circuit 20 that selects the second receiving circuit output. an image display means 21 for inputting data and displaying the image on the screen; a second system control unit 22 for controlling the system controller of the second terminal; and a power supply circuit 11 for the first terminal 1. It is provided with a power supply circuit 23 etc. for supplying power to.

The screen 16 is a removable device that displays images taken by the video camera 4 of the first unit 1, and is made of a CRT, liquid crystal device, or the like.

The human power means 17 (i) is constructed so that the control items shown in FIG. 3 can be individually specified.

The system is configured so that a Guineau signal corresponding to each control item can be outputted by operating the following keys: (1) and (2) which are used for each control item. .

The control signal output circuit 18 receives a key from the manual means 17.
In response to the signal and the clock from the second system control unit 22, it outputs a control signal for controlling the control means 9 of the video camera 1. When the human power means 17 is used to operate a key for tilting or moving, the clock used for -1 baseband transmission is changed from the beginning of the second period B3 to period B3 of the burst cycle period B. 1: Insert 'i pieces. Select the operation time of this input means 17, '7. The number of burst cycles to which this control signal is added is proportionally increased by 1.
The connection between the transmission path 3 and the second receiving circuit 20 is selectively switched between the connection between the transmission line 3 and the second receiving circuit 20, and the connection between the transmission line 3 and the second receiving circuit 20 is switched between Ru.

That is, the second system control unit 22 controls the period B'I of each burst period to 1. 1. The second receiving circuit 20 of the second terminal and the transmission...
) for controlling the switch 19 and for controlling the period B of each berth l-period.
2, the second switch 9 is controlled to connect the control signal output circuit 18 of the second terminal to the transmission line 3. still,
In this second switching, 19 connects the transmission line 3 and the second receiving circuit 20.
The system is configured so that when the system is started up, upstream information can be transmitted from the first terminal to the second terminal.

The second receiving circuit 20 receives the baseband transmission signal transmitted from the first terminal 1 during period B1 of the burst period B, and regenerates the clock! 2. Play the video signal.

The first image display stage 21 receives the video signal from the second receiving circuit 20 and forms a signal for displaying a corresponding image on the screen 16.

The second system control unit 22 receives the reproduced clock and forms necessary control signals from the second terminal 2 to the first terminal.
A timing signal is generated to determine the transmission timing of the control signal to be transmitted to the terminal 1, and is sent to the control signal output circuit 18. It also influences the switch control signal that determines the connection mode of the second switch 17, and switches it to the second switch 17.
The switching device has a 171m shrine.

The power supply circuit 23 is connected to the transmission line 3 via an inductance 21) 7, and is connected to the power supply circuit 1 of the first terminal device 1.
Are you trying to give power to 1? ]. '! - At the same time, power is supplied to each component of the second terminal 2 (7).

The transmission line 3 is composed of a pair of bare wires in order to improve construction efficiency and to support various deployments of the system 12. ,
The second transmission line uses isolated balanced transmission using a pulse transformer as an interface with each terminal.

Next, an overview of the operation of the two-way communication device of the present invention will be explained. The visitor uses a separately provided intercom or the like to inform the administrator (person at home) of the second terminal 2 of his/her visit. Upon receiving this notification, manually or automatically (the means for doing so are not indicated, but it is recognized as easy for those skilled in the art),
The power supply circuit 23 of the second terminal is activated. And 1,
The power supply circuit 23 supplies power to each of the first and second terminals.

A video camera 4 photographs the visitor and transmits the video signal to an image processing circuit 5. This image processing circuit converts the video signal from analog to digital, performs compression processing, and stores it in memory.
Stores a compressed image for one frame. This compressed image is edited by the transmission frame configuration unit 6 under the control of the first system control unit 10 so as to be transmitted using the baseband transmission method during period B1 of the burst period B in FIG. , processing is performed such that one frame worth of images is transmitted per one burst period. This transmission signal is transmitted to the second terminal via the first switch 7 and the transmission line 3.

The second terminal 2 receives this transmission signal, and the received signal is input to the second receiving circuit 20 via the second switch 19. This second receiving circuit performs the inverse conversion of the processing performed on the first terminal side and outputs a video signal. The video signal is input to the image display means 21, and the screen 16 displays the visitor.

If the user of the second terminal confirms the image on the screen and wishes to change the shooting status (zoom, pan, tilt), he/she can input the desired image using the input means 17. command to change the video camera's shooting status so as to obtain the desired result.

For example, if you control a key that commands "tilt up",
The control signal output circuit 18 adds 15 pulses to the period B3 in the burst period B, as described above, under the control of the second system control section 22. This control signal is supplied to the first terminal 1 via the second switch 19 and the transmission line 3, and the first terminal transmits it to the first receiving circuit 8 via the first switch 7. . This first receiving circuit interprets the user's intention and controls the video camera 4 according to the user's intention.
The control means 9 is controlled in order to add to the .

In this way, the first and second terminals and the transmission line 3
The terminal 1 is configured to be suitable for transmitting information (uplink information) from the terminal 1 to the second terminal, and for transmitting information (downlink information) in the opposite direction. Normally, both the transmission and reception systems of the first and second terminals are designed to allow transmission of information with a larger amount of information, but in the present invention, as described above, uplink and downlink Since the transmission and reception systems are suitable for transmitting each type of information, the configuration of the device can be simplified.

The present invention has been described above with reference to an embodiment of a doorbell.
The present invention is not limited to this, and can be used in various devices constituting a two-way communication system in which there is a large difference in the amount of uplink information and downlink information.

(G) Effects of the Invention As described above, the present invention employs a transmission system suitable for each different amount of information, so the configuration of each terminal can be simplified. In addition, for downlink information with a small amount of information, a different number of pulses is assigned to each of multiple control items in stages, and the first receiving circuit of the first terminal that receives the pulses has a wide range of counts regarding the meaning of each control item. Therefore, there is an increase or decrease in the pulse within the permissible range (that is, a variation within the permissible range) with respect to the assigned pulse6.
The control item corresponding to the assigned pulse can be accurately recognized.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the door phone according to this embodiment. FIG. 2 is a diagram showing a time chart (one cycle) of transmission signals used in this door phone. FIG. 3 is a diagram illustrating control items and control signals (number of pulses) assigned to the control items for controlling the video camera. 1 is the first terminal, 2 is the second terminal, 3 is the transmission path, 4
is a video camera, 5 is an image processing circuit, 6 is a transmission frame component, 7 is a first switch, 8 is a first receiving circuit, 9 is a control means, ] 0 is a first system control unit, 11 is a power supply circuit, 1
6 is a screen, 17 is an input means, 18 is a control means output circuit, 19 is a second switch, 20 is a second receiving circuit, 21 is an image display means, 22 is a second system control section, and 23 is a power supply circuit.

Claims (3)

[Claims] (1) Comprising a first terminal, a second terminal, and a transmission path to which each terminal is connected to each terminal, and transmits information (uplink) from the first terminal to the second terminal. information) and information (downlink information) from a second terminal to a first terminal in a time-sharing manner to the other party's terminal by relaying the transmission path and transmitting the information in both directions. The information is converted into a digital signal within the first terminal, and the uplink information is transmitted in the baseband on the transmission path, while the downlink information is transmitted on the baseband in the transmission path. A two-way communication characterized in that the downlink information is expressed by the number of clock pulses used in transmission or the number of clock pulses related thereto, and the amount of the downlink information is sufficiently smaller than the amount of uplink information. Device. (2) The two-way communication device according to claim (1), wherein the downlink information includes a plurality of control items, and a stepwise different number of pulses are assigned to each control item. (3) A first terminal, a second terminal, and a transmission path to which each terminal is connected to each terminal, and transmits information (uplink) from the first terminal to the second terminal. information) and information (downlink information) from a second terminal to a first terminal in a time-sharing manner to the other party's terminal by relaying the transmission path and bidirectionally transmitting the information. The first terminal includes a video camera, an image processing circuit that digitally processes images taken by the video camera, and a transmission frame configuration that forms a transmission signal for baseband transmission of the digital signal from the image processing circuit. a first switch that selects supply of the transmission signal to the transmission path; and a first switch that receives a control signal from the second terminal via the transmission path and the first switch. a receiving circuit; and a control means driven by the output of the first receiving circuit to control the state of the video camera, while the second terminal has a screen for displaying the image and a control means for instructing the state of the video camera. an output circuit that receives an instruction from the input means, determines the number of pulses to be output based on the instruction, and outputs a control signal, and supplies the control signal from the output circuit to the transmission path. a second switching device that selects a second terminal; a second receiving circuit that receives a transmission signal from the first terminal via the transmission path and the second switching device; and a second receiving circuit that receives an output of the second receiving circuit. and an image display means for displaying the image on the screen, wherein the amount of the downlink information is sufficiently smaller than the amount of uplink information.