JPH05219073A - Console unit connecting device for home bus system - Google Patents

Abstract

PURPOSE:To prevent deterioration of a video signal by providing a pair of coils having a characteristic by which AC impedance becomes high in a transmission frequency band of the video signal, and a voice terminal connecting device. CONSTITUTION:A voice terminal connecting device 4 is constituted of coils 5a, 5b having a characteristic for allowing a sound signal to pass through, and becoming high impedance in a video signal frequency band, and leader lines 6a, 6b, and in a sound signal frequency band, an insertion loss is suppressed small. A video terminal connecting device 8 is constituted of a home bus side connecting part 9, leader lines 12a, 12b, and a terminal side connecting part 13. A terminal side video system connecting part 24 is constituted of a resistor 26 having a characteristic of the same value as characteristic impedance of leader lines 23a, 23b in the video signal frequency band, capacitors 25a, 25b of a characteristic for allowing a video signal to pass through, and becoming high impedance in the sound signal frequency band, and capacitors 27a, 27b for allowing the video signal to pass through, and obstructing an excessive DC signal, and sends out the video signal transmitted to a video signal receiving part 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a specific pair of twisted pair wires of a home bus composed of a plurality of twisted pair wires, which are modulated to a high frequency band which does not overlap with a voice signal and a transmission frequency band of the voice signal. The present invention relates to a home bus system terminal equipment connection device for connecting various terminal equipments to a home bus in a home bus system for transmitting a video signal.

[0002]

2. Description of the Related Art FIG. 2 shows the configuration of a conventional home bus system having a camera doorphone call function. Figure 2
In the home bus composed of a plurality of twisted pair wires, a specific pair of twisted spare wires 33a, 33b
A voice terminal 34 with a camera such as a camera doorphone handset having a function of transmitting an audio signal and a video signal modulated in a transmission frequency band that does not overlap with the audio signal is provided at one end of the
On the twisted pair wires 33a and 33b, a voice terminal 36 represented by a telephone and modular cords 37a and 37b via modular cords 35a and 35b.
And a video terminal 38 typified by a monitor TV via
A video / audio terminal 40 represented by a telephone with a monitor is connected to an arbitrary place through the modular cords 39a and 39b. The video / audio terminal 40 has a video signal receiving unit 41 for receiving a video signal and an audio signal transmitting unit 42 for bidirectionally transmitting an audio signal.

Further, in the transmission frequency band of the video signal transmitted from the audio terminal 34 with a camera, a terminator 34 having a resistor having the same value as the characteristic impedance of the twisted pair wires 33a and 33b is connected to the ends of the twisted pair wires 33a and 33b. To be done. The image input by the audio terminal 34 with a camera is displayed on the image terminal 38 via the twisted pair wires 33a and 33b and the modular cords 37a and 37b, and at the same time, the twisted pair wires 33a and 33b.
Also, it is transmitted to the video signal receiving unit 41 of the video / audio terminal 40 via the modular codes 39a and 39b and displayed on the video / audio terminal 40.

Further, the voice is the twisted pair wires 33a, 33.
b and the modular cords 35a and 35b, bidirectional transmission is performed between the camera-equipped voice terminal 34 and the voice terminal 36 to make a call between the camera-equipped voice terminal 34 and the voice terminal 36, and the twisted pair wires 33a and 33b. And the audio signal transmission unit 42 in the audio terminal 34 with a camera and the audiovisual terminal 40 via the modular codes 39a and 39b.
Is transmitted and received bidirectionally, and both the audio terminal 34 with a camera and the audiovisual terminal 40 talk.

[0005]

However, in the home bus system having the TV doorphone call function of the conventional configuration, the connection point of the twisted pair line of the home bus and the modular cord, and the modular cord and the terminal are transmitted during the video signal transmission. The video signal transmitted at the connection point with the equipment is reflected, and a standing wave is generated on the twisted pair line of the home bus.

Therefore, there is a problem in that the transmitted video signal is distorted, and the quality of the video demodulated by the video terminal or the video / audio terminal is deteriorated.

[0007]

In order to solve the above problems, as a first means, as a first means, a transmission frequency band of a video signal is transmitted between a specific pair of twisted pair wires and a voice terminal while passing a voice signal. A voice terminal connecting device is provided which is composed of a pair of coils having characteristics of increasing AC impedance and a lead wire such as a modular cord.

As a second means, between a specific pair of twisted pair wires and a video terminal, the AC impedance is high in the transmission frequency band of the audio signal, and the home in which the twisted pair wire side is high impedance in the transmission frequency band of the video signal. Video terminal consisting of a bus side connection part, a lead wire such as a modular cord, and a terminal side connection part in which the characteristic impedance of the lead wire is equal to the transmission signal frequency band of the video signal and the AC impedance is high in the transmission frequency band of the audio signal Provide a connection device.

As a third means, between the specific pair of twisted pair wires and the audiovisual terminal, the AC impedance is high in the transmission frequency band of the audio signal, and the twisted pair line side has a high impedance in the transmission frequency band of the video signal. Bus side connection part, lead wire such as modular cord, terminal side video system connection part where the characteristic impedance of the lead wire in the video signal transmission frequency band is equal to the AC impedance in the audio signal transmission frequency band, and the audio signal A video / audio terminal connection device is provided which is composed of a terminal-side audio system connection section that passes through the terminal and has a high AC impedance in the transmission frequency band of the video signal.

[0010]

According to the present invention, when a plurality of terminal devices such as a voice terminal, a video terminal, and a video / audio terminal are connected to a specific pair of twisted pair wires of a home bus by using the terminal device connecting device having the above-described structure, a video signal Since the terminal device can be connected with high impedance in the transmission frequency band, the characteristic impedance of the twisted pair wire of the home bus is to be prevented from being reflected at the connection point of the terminal device. Further, in the audio signal frequency band, it is possible to avoid a decrease in the characteristic impedance of the specific pair of twisted pair wires of the home bus and the lead wire of the terminal device, and to suppress the insertion loss.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A home bus system terminal equipment connecting apparatus according to an embodiment of the present invention will be described below with reference to FIG. As shown in FIG. 1, in a home bus composed of a plurality of twisted pair wires, a specific pair of twisted pair wires 1a, 1
A voice terminal 2 with a camera represented by a camera doorphone handset having a function of transmitting an audio signal and a video signal modulated in a transmission frequency band that does not overlap the audio signal is connected to one end of b, and the twisted pair wire 1a, At the end of 1b, the twisted pair wire 1a,
The terminator 3 formed of a resistor having the same value as the characteristic impedance of 1b is connected.

The voice terminal connection device 4 is a device for connecting a voice terminal 7 represented by a telephone or the like to an arbitrary place on the twisted pair lines 1a and 1b. The audio terminal connection device 4 is composed of coils 5a and 5b having characteristics of passing an audio signal and having a high impedance in a video signal frequency band, and lead wires 6a and 6b such as modular cords,
Insertion loss is kept small in the audio signal frequency band.
Also, in the video signal frequency band, twisted pair wire 1
The characteristic impedances of a and 1b are prevented from decreasing, and the reflection of the video signal transmitted on the twisted pair lines 1a and 1b is avoided at the connection point between the twisted pair lines 1a and 1b and the voice terminal connection device 4.

Reference numeral 8 is a video terminal connection device. The video terminal connection device 8 is a video terminal 1 represented by a monitor TV.
6 is a device for connecting 6 to an arbitrary place on the twisted pair wires 1a and 1b. The video terminal connecting device 8 includes a home bus side connecting portion 9 and a leader line 12 such as a modular cord.
a, 12b, and the terminal-side connection unit 13.

The home bus side connection section 9 has a high impedance on the connection side of the capacitors 10a and 10b having a characteristic of passing a video signal and having a high impedance in the audio signal frequency band, and a connecting line of the twisted pair wires 1a and 1b, and a lead wire 12a, The connecting side of 12b is composed of a transformer 11 having the same characteristic as the characteristic impedance of the lead lines 12a and 12b in the video signal frequency band, and avoids the impedance drop of the twisted pair lines 1a and 1b in the audio signal frequency band, , The impedance of the twisted pair wires 1a and 1b is prevented from decreasing, and the twisted pair wires 1a and 1b are prevented from decreasing in impedance.
It is possible to avoid reflection of the video signal transmitted on the twisted pair wires 1a and 1b at the connection point between the video terminal connection device 8 and the video terminal connection device 8.

Further, the terminal side connection portion 13 has a resistor 14 having a characteristic having the same value as the characteristic impedance of the lead lines 12a and 12b in the video signal frequency band, and a capacitor 15a which passes the video signal and blocks an excessive DC signal. , 15
b, which avoids reflection of a video signal transmitted from the twisted pair wires 1a and 1b through the video terminal connection device 8 at a connection point between the video terminal connection device 8 and the video terminal 6, and prevents the video signal from the video terminal 6 from being reflected. The excessive DC signal is blocked to prevent the resistor 14 and the transformer 11 from being destroyed.

Reference numeral 17 is a video / audio terminal connection device. The video / audio terminal connection device 17 is a device for connecting the video / audio terminal 30 represented by a telephone with a monitor to any place on the twisted pair lines 1a and 1b. The video / audio terminal connection device 17 includes a home bus side connection section 18, leader lines 23a and 23b such as modular cords, a terminal side video system connection section 24, and a terminal side audio system connection section 28.

The home bus side connecting portion 18 is a capacitor 19a, 19b, 21a, which has a characteristic of passing a video signal and having a high impedance in an audio signal frequency band.
21b, the connection side of the twisted pair wires 1a and 1b has a high impedance, and the connection side of the lead wires 23a and 23b has a characteristic having the same characteristic as the characteristic impedance of the lead wires 23a and 23b in the video signal frequency band. , The coil 22a, 22b having a characteristic of having a high impedance in the video signal frequency band, suppressing the insertion loss in the audio signal frequency band, and the twisted pair wire 1 in the video signal frequency band.
It is possible to avoid a decrease in the characteristic impedance of a and 1b, and to avoid the reflection of the video signal transmitted on the twisted pair wires 1a and 1b at the connection point between the twisted pair wires 1a and 1b and the video / audio terminal connection device 17. ..

The terminal side video system connecting section 24 has a resistor 26 having the same characteristic as the characteristic impedance of the lead lines 23a and 23b in the video signal frequency band, and the video signal passing therethrough to have a high impedance in the audio signal frequency band. 25a and 25b having the following characteristics, and a condenser 27 that passes an image signal and blocks an excessive DC signal
a and 27b, and sends the video signal transmitted to the video signal receiving unit 31 of the video / audio terminal 30. With the above configuration, the terminal-side video system connection unit 24 connects the video / audio terminal connection device 17 and the video / audio terminal 30 to the video / audio terminal connection device 17 from the twisted pair lines 1a and 1b.
The reflection of the video signal transmitted via the video signal is prevented, and the excessive direct current signal from the video signal receiving unit 31 of the video / audio terminal 30 is blocked to prevent the resistor 26 from being destroyed.

The terminal-side audio system connection section 28 is composed of coils 29a and 29b having characteristics of passing an audio signal and having a high impedance in the video signal frequency band, and connected to the audio signal transmission section 32 of the video / audio terminal 30. To be done. The twisted pair line 1 is provided at the connection point between the terminal side audio system connection unit 28, the video / audio terminal connection device 17, and the video / audio terminal 30.
It is possible to avoid reflection of a video signal transmitted from a and 1b via the video / audio terminal connection device 17, and to suppress insertion loss in the audio signal frequency band to be small.

The video input from the audio terminal 2 with a camera is displayed on the video terminal 16 via the twisted pair lines 1a and 1b and the video terminal connection device 8, and at the same time, the twisted pair lines 1a and 1b and the video and audio terminal connection. Device 1
It is transmitted to the video signal receiving unit 31 of the video / audio terminal 30 via 7 and is displayed on the video / audio terminal 30.

Voice is bidirectionally transmitted between the camera-equipped voice terminal 2 and the voice terminal 7 via the twisted pair lines 1a and 1b and the voice terminal connection device 4, and the voices of the camera-equipped voice terminal 2 and the voice terminal 7 are transmitted. A call is made between the two parties, or bidirectional transmission is performed between the camera-equipped audio terminal 2 and the audio signal transmission unit 32 in the audio / video terminal 30 via the twisted pair wires 1a and 1b and the audio / video terminal connection device 17, A call is made by both the attached audio terminal 2 and the audiovisual terminal 30.

By connecting the audio terminal 7, the video terminal 16 and the audiovisual terminal 30 to the twisted pair lines 1a and 1b through the audio terminal connecting device 4, the video terminal connecting device 8 and the audiovisual terminal connecting device 17 described above. , Twisted pair wires 1a, 1b of the home bus during video signal transmission
Can be prevented from being reflected at a connection point between the terminal device connection device and each terminal device connection device, and at the connection point between each terminal device connection device and each terminal device, and demodulated by the video terminal 16 and the audiovisual terminal 30. It is possible to avoid degrading the image quality.

[0023]

As described above, the home bus system terminal equipment connection device of the present invention can connect the home bus and each terminal equipment with a simple circuit configuration that does not require power feeding. When many terminal devices are connected to the home bus via the connection device, the characteristic impedance of the line of the home bus is kept stable by receiving high impedance in the transmission frequency band of the video signal, and the terminal device and the home bus are connected. It is possible to avoid reflection of the video signal at the connection point of and to transmit the video signal in a good state.

Further, by receiving with a high impedance in the audio signal frequency band, it is possible to avoid a decrease in the characteristic impedance of the home bus and each lead wire in the audio signal frequency band, and to suppress the insertion loss.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a home bus system using a terminal device connection device for a home bus system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a home bus system in a conventional example.

[Explanation of symbols]

1a, 1b, 33a, 33b Twisted pair wire 2, 34 Camera-equipped audio terminal 3, 34 Terminator 4 Audio terminal connection device 7 Audio terminal 8 Video terminal connection device 16 Video terminal 17 Video audio terminal connection device 30 Video audio terminal 35a, 35b , 37a, 37b, 39a, 39b Modular cord

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location H04N 7/18 H 7337-5C

Claims (7)

[Claims] 1. An audio signal and a video signal modulated in a high frequency band that does not overlap with a transmission frequency band of the audio signal by using a specific pair of twisted pair wires in a home bus composed of a plurality of twisted pair wires. In a home bus system for transmission, a voice terminal typified by a telephone is connected to the specific pair of twisted pair wires via a lead wire such as an antireflection device and a modular cord made of a coil, and the coil serves as the voice signal. A terminal device connecting device for a home bus system, which has a characteristic of having a high AC impedance in a transmission frequency band of the video signal. 2. An audio signal and a video signal modulated in a high frequency band which does not overlap with a transmission frequency band of the audio signal by using a specific pair of twisted pair lines of a home bus composed of a plurality of twisted pair lines. In the home bus system for transmission, the specific pair of twisted pair wires are connected via a home bus side connecting portion having an antireflection function, a lead wire such as a modular cord, and a terminal side connecting portion having an impedance matching function. A terminal device connecting device for a home bus system, characterized in that a video receiving terminal typified by a monitor is connected. 3. The pair of capacitors on the home bus side according to claim 2, wherein the pair of capacitors have a characteristic of having a high AC impedance in a transmission frequency band of the audio signal and passing through the video signal, and the specific pair of twisted pair. A home bus system terminal equipment connection device, characterized in that the line side has a high impedance and the connection side of the leader line is composed of a transformer having a characteristic equal to the characteristic impedance of the leader line in the frequency band of the video signal. 4. The terminal side connection unit according to claim 2,
It is composed of a resistor having a characteristic equal to the characteristic impedance of the lead wire in the frequency band of the video signal, and a pair of capacitors passing the video signal and having a high AC impedance in the transmission frequency band of the audio signal. A terminal device connecting device for a home bus system, which is characterized in that: 5. An audio signal and a video signal modulated in a high frequency band which does not overlap with a transmission frequency band of the audio signal by using a specific pair of twisted pair lines of a home bus composed of a plurality of twisted pair lines. In the home bus system for transmission, the specific pair of twisted pair wires has a home bus side connecting portion having antireflection function, a leader line such as a modular cord, a terminal side video system connecting portion and a terminal side audio system connecting portion. A terminal device connection for a home bus system, characterized in that a video / audio receiving terminal typified by a telephone with a monitor is connected to the home bus via a terminal side connection section having an impedance matching function composed of apparatus. 6. The home bus side connecting portion according to claim 5, wherein the connection side of the specific pair of twisted pair wires has a high impedance, and the connection side of the lead wire has a characteristic impedance of the lead wire in the frequency band of the video signal. A transformer having a characteristic equal to, a pair of capacitors connected to the primary side and the secondary side of the transformer, passing the video signal, and having a high AC impedance in the transmission frequency band of the audio signal, It is characterized by comprising a coil having a characteristic of having a high AC impedance in a transmission frequency band of the video signal and passing the audio signal through a connection point between the pair of twisted pair wires and the lead wire. Terminal equipment connection device for home bus system. 7. The plurality of pairs of capacitors according to claim 5, wherein the terminal-side video system connection section has a characteristic of passing the video signal and having a high AC impedance in a transmission frequency band of the audio signal. In the frequency band of the video signal, it is composed of a resistor having a characteristic equal to the characteristic impedance of the lead wire, and the terminal side audio system connecting portion passes through the audio signal and has a high AC impedance in the transmission frequency band of the video signal. A terminal device connection device for a home bus system, which is composed of a pair of coils having characteristics.