JPH11112959A - Incoming band measurement rod for catv transmission network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce test times without interrupting an outgoing signal sent from a cable television CATV broadcast station to a subscriber. SOLUTION: For an incoming band measurement rod of a CATV transmission network, a connection piece 14 is projected upward to a coupling bolt 12, to be coupled with a 2-way coupler at one side and a bolt 13 to be connected to a measurement device is formed integrally at the other side, a power supply separate section 15 is configured in the inside of one side, at which the coupling bolt 12 is formed to eliminate a power supply component included in a signal component, low-pass filter 16 is connected to the power supply separate section 15 to detect only a low-frequency signal from the signal from which the power supply component is eliminated, and noise included in the incoming signal sent from the subscriber to the CATV broadcast station is detected so that the outgoing signal sent from the CATV broadcast station to the subscriber is not interrupted and at the some time the test time can be shortened even with few inputs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring cable for an upward band in a CATV transmission network, and more specifically, to provide a CATV (Cable Television) service from a subscriber to a CATV broadcasting station. Even when detecting the presence or absence of noise included in the upward signal transmitted to the subscriber, the time required for the test can be reduced while the downward signal transmitted from the CATV broadcast station to the subscriber is not interrupted. The present invention relates to an upward band measuring rod of a CATV transmission network.

[0002]

2. Description of the Related Art Generally, CATV services are provided by CAs.
It is well known that communication in both directions, that is, transmission of a downward signal for transmitting a broadcast signal from a TV broadcast station to each subscriber side and transmission of an upward signal from a subscriber side to a CATV broadcast station is possible. Is a fact. The downward signal transmitted from the CATV broadcast station to the subscriber side is converted into an RF signal having a band of about 54 MHz, output, and transmitted from each subscriber side to the CATV broadcast station. A method of converting a signal into an RF signal in a band of 5 to 30 MHz and outputting the converted signal is mainly used.

[0005] However, a frequency band of 5 to 30 MHz, which is a frequency band in which an upward signal is transmitted from a subscriber side to a CATV broadcasting station, is used.
Is the band most vulnerable to external radio waves, so there is a problem that noise must be completely prevented.
Conventionally, signals are transmitted in both directions between the broadcasting station 1 and a large number of subscribers 9 while providing a two-way service through a CATV transmission system as shown in FIG.
And a plurality of amplifiers 2, 3, 4, etc. for compensating for the attenuation of the upward or downward signal between the broadcast station 1 and the subscriber 9, etc., and the broadcast signal from the broadcast station 1 is distributed in a tree format. Numerous splitters for transmitting to subscribers 9 etc.
5, 6, 7, etc., and a number of branching devices 8 installed in an area where the above-mentioned subscribers 9 are densely provided and branching and supplying signals to each subscriber 9 on the same distribution line. did.

Here, the amplifiers 2, 3, 4 and the like need to be installed at a distance of up to 600 m on the transmission line in order to prevent the broadcast signal from being reduced to such an extent that the broadcast is affected. In order to provide good quality broadcasting service, the service is installed every 200m and the distributors 5, 6, 7
Are bidirectional couplers having a attenuation function that varies the degree of attenuation depending on the transmission distance so that all subscribers transmit and receive broadcast signals of uniform quality.
coupler) is mainly used.

[0005]

However, in the conventional CATV transmission system as described above, when measuring the noise included in the upward signal, it is necessary to measure the noise flowing from the branch line and the distributor. Is a state in which one set connects a measuring instrument to an amplifier to analyze the state of noise, and the other set measures while separating the subsequent manual elements (other splitters or splitters) one by one. Down signal transmitted from the broadcasting station during the inspection section was also interrupted,
In the case of the upward service, the upward measurement of the negative element becomes impossible, and two sets are always required for the measurement of the noise, so that the maintenance staff and equipment costs are increased.
There are disadvantages such as that much time is required for measurement.

That is, in the case of a branch line test of a branching device, after removing the module of the branching device, it is performed by a process of checking a line with a fault detecting device for a moving shaft line and measuring an upward signal with a pre-amplifier. Therefore, two aerial work vehicles and a lot of working time are required, and in the case of the incoming line test of the distributor, the upward signal while removing the distributor module from the first distributor to the terminal distributor sequentially. This is performed by measuring a fulcrum into which noise is introduced, so that two work vehicles at high altitude and a lot of work time are required, and a broadcast signal which is a downward signal is also interrupted at the time of measurement. was there.

As a result, the present invention provides a CAT
When detecting the presence or absence of noise included in the upward signal transmitted to the V broadcast station, a simple operation of inserting a measuring rod into the branching unit or distributor to be measured allows a lower transmission from the CATV broadcast station to the subscriber. SUMMARY OF THE INVENTION It is an object of the present invention to provide an upper band measuring rod for a CATV transmission network, which can reduce a test time with a small amount of manpower without interrupting a heading signal.

[0008]

In order to achieve the above object, an upward band measuring rod of the CATV transmission network according to the present invention has a connecting piece projecting from a connecting bolt portion for connecting to a one-way bidirectional coupler. At the same time as molding, the other side is integrally formed with a bolt part for connecting to the measuring instrument, and the inside of one side where the coupling bolt part is formed constitutes a power supply separation part and is included in the signal component. The power supply component is removed, and a low-pass filter is connected to the power supply separation unit to detect only the low-frequency signal from the signal from which the power supply component has been removed and transmit the signal to the CATV broadcasting station from the subscriber side. By detecting the noise included in the upward signal, the downward signal transmitted from the CATV broadcasting station to the subscriber is not interrupted, and the test time can be reduced with less human labor.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 2 shows a configuration of a measuring rod according to an embodiment of the present invention, in which a connecting bolt portion 12 and a bolt portion 13 are formed on both sides of a measuring rod main body 11 so as to include a power component. The transmitted signal is transmitted, and the two-way coupler (Fig. 1)
Bolts 12 for connecting to the distributor and the branching device)
At the same time, the connecting piece 14 is formed so as to protrude, and at the same time, a measuring device for measuring the presence or absence of noise (Noise) is connected to the other bolt part 13, so that the coupling bolt part 12 is formed. A power supply separation unit 15 is configured inside the main body 11 to remove a power supply component included in a signal,
A low-pass filter 16 is connected to the power supply separation unit 15 to remove the power supply component.
By detecting an upward signal, which is an RF signal in the MHz band, the presence or absence of noise included in the upward signal is detected through a measuring device connected to the bolt unit 13.

FIG. 3 shows a detailed configuration of a measuring rod according to an embodiment of the present invention. Two capacitors C1 and C2 are connected to a connecting piece 14 of a measuring rod main body 11 on a side of a coupling bolt portion 12.
Power supply separation unit 15 composed of C2 and inductance L1
To bypass the power supply component included in the signal flowing through the connection piece 14, and the signal from which the power supply component has been removed by the power supply separation unit 15 has an inductance L.
2, L3, L4, L5, etc. in series and the inductances L2, L3, L4, L5 before and after the capacitor C3,
By passing through a low-pass filter 16 grounded through a series connection of C7 or inductances L6, L7, L8 and capacitors C4, C5, C6, only the upward signal, which is an RF signal in the 5 to 30 MHz band, is passed. The noise is transmitted to the measuring instrument connected to the bolt section 13 (Nois
e) Presence or absence of presence is accurately detected.

Further, the measuring rod main body 11 transmits a broadcast signal transmitted from the broadcasting station 1 through a number of amplifiers 2, 3, 4, etc., as shown in FIG.
7 is distributed to each subscriber 9 through a number of distributors 8 on the same distribution line, so that the broadcast station 1 transmits downward to each subscriber 9 and the like. Although little noise is generated in the broadcast signal, which is a signal, the signal transmitted upward from each subscriber 9 or the like to the broadcast station 1 contains a lot of noise.

Therefore, as shown in FIG.
The connecting bolt portion 12 formed on one side is screwed to the nut portion 23 after the closed cap 22 on the output side 21 of the distributors 5, 6, 7 of FIG. When fastened and coupled, the signals transmitted through the input side 24 and transmitted to the plurality of subscribers 9 through the multiple output sides 21 and transmitted from each subscriber 9 and the like to the broadcasting station 1 and flowing through the internal distribution circuit are connected. It can be detected through the piece 14.

After removing the power component from the signal transmitted to the measuring rod main body 11 by the internal power source separation unit 15,
If the low-pass filter 16 detects only the low-frequency component of the RF signal of the 5 to 30 MHz band, the upward signal transmitted from the subscriber 9 to the broadcasting station 1 is output to the bolt 1 of the measuring rod body 11.
Since it is transmitted to the measuring device connected to 3, it can be confirmed whether or not noise is included.

When the measuring rod body 11 is connected to one of the output sides of the splitter 8 of FIG. 1 which is a two-way coupler by screwing, it is transmitted through this input side and is transmitted through a plurality of output sides. A signal transmitted to the subscriber 9 or the like or a signal transmitted from each subscriber 9 or the like to the broadcasting station 1 can be detected. Therefore, after removing the power component from the signal transmitted to the measuring rod main body 11 by the internal power source separation unit 15, the low-pass filter 16 removes the power component from 5 to 30 MHz.
When only the low-frequency component of the band RF signal is detected, the upward signal transmitted from the subscriber 9 to the broadcasting station 1 is transmitted to the measuring rod body 11.
Is transmitted to the measuring device connected to the bolt portion 13 of the first embodiment, so that it is possible to confirm whether or not noise is included.

The present invention describes the configuration according to one embodiment, and the present invention should not be analyzed in a limited manner by such an embodiment. In particular, the configuration of the power supply separation unit and the low-pass filter has been described by selecting only one of various possible configurations.

[0016]

Therefore, according to the upward band measuring rod of the CATV transmission network of the present invention, a connecting bolt and a bolt portion are formed on both sides of the measuring rod main body so that a signal including a power component is transmitted through the connecting bolt. In order to measure the presence / absence of noise on the other bolt part, the connecting piece is formed so as to be integrally protruded from the coupling bolt part for connecting with the two-way coupler at the part to be measured. And a power supply separating unit is formed inside the main body in which the coupling bolt portion is formed to remove and control a power supply component included in a signal. By connecting a low-pass filter, it is possible to accurately detect noise included in an upward signal, which is a low-frequency signal, in a signal from which power components have been removed.

Further, the connecting bolt portion on one side of the measuring rod main body is fastened and screwed to the nut portion after separating the closed cap on the output side of the distributor as the two-way coupler. Then, the signal mutually transmitted between the output side and the input side can be detected, the power supply component is removed by the internal power supply separation part with the measuring rod body, and the low pass filter of 5 to 30 MHz band. By detecting only the low frequency component that is the RF signal, whether the upward signal transmitted from the subscriber to the broadcasting station contains noise by using a measuring instrument connected to the bolt portion of the measuring rod body It can be easily confirmed whether or not.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a transmission system for a general two-way CATV service.

FIG. 2 is a schematic diagram showing a configuration of the present invention.

FIG. 3 is a circuit diagram showing a detailed configuration of the present invention.

FIG. 4 is a schematic diagram showing a use state of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Measurement rod main body 12 ... Connection bolt part 13 ... Bolt part 14 ... Connection piece 15 ... Power supply separation part 16 ... Low-pass filter

Claims (5)

[Claims] 1. A connecting bolt portion and a bolt portion are formed on both sides of a measuring rod main body so that a signal including a power component is transmitted through the connecting bolt portion so as to be connected to a two-way coupler of a portion to be measured. A connection piece is formed so as to protrude from the connection bolt portion, and a power supply separation portion and a low-pass filter are provided inside the body in which the connection bolt portion is formed to remove power components. An upstream band measurement rod for a CATV transmission network, wherein the upstream signal is configured to be detected at a volt portion. 2. The power supply separating section connected to the connection piece of the measuring rod main body is constituted by two capacitors and an inductance so as to bypass a power supply component included in a signal flowing through the connection piece. The upward measuring band of the CATV transmission network according to claim 1, characterized in that: 3. A low-pass filter connected to a power supply separation part of the measuring rod main body, wherein the signal from which the power supply component has been removed by the power supply separation part passes through a series connection of four inductances while the signal of the inductance is removed. The capacitor is configured to be grounded through a series connection of a capacitor or an inductance and a capacitor in the preceding and succeeding stages so that only an upward signal, which is an RF signal in a 5 to 30 MHz band, is transmitted to the volt unit. Item 7. An upward measuring band of the CATV transmission network according to Item 1. 4. A connecting bolt on one side of the measuring rod main body is fastened by screwing to a nut after separating a distributor which is a two-way coupler and one closed cap on the output side of the branching device. 2. The upper band measuring rod according to claim 1, wherein the upper band is measured. 5. A measuring device for measuring the presence or absence of noise is connected to the other bolt portion of the measuring rod main body by screwing to measure whether or not the upward signal includes noise. The upward band measuring rod of the CATV transmission network according to claim 1, wherein