JPH03135294A - State discrimination method for two-way catv system - Google Patents

Abstract

PURPOSE:To speed up dealing at the time of the occurrence of abnormality by generating the binary signal of either normality or the abnormality, and displaying an abnormality occurring place by specifying it as one of the two-way amplifiers or a transmission line between two two-way amplifiers on the basis of the combination of the binary signals of the neighboring two two-way amplifiers. CONSTITUTION:In an abnormal spot specifying means 53, the binary state signals of two two-way amplifiers (A1; A2, A2; A3, A3; A4...) neighboring each other are compared with an abnormal spot specifying table. The abnormal spot specifying table is a table to coordinate the combination of the binary state signals with the abnormality occurring place. Then, when the abnormality occurs, it is discriminated in what two-way amplifier the abnormality occurs, or in the transmission line between what two-way amplifiers it occurs. On the basis of a discriminated result obtained in this way, the abnormality occurring place is displayed at a monitor device 71 installed in the neighborhood of a head end. Thus, the abnormality can be dealt with quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for determining the state of a bidirectional CATV system.

The method of the present invention allows detailed identification of the abnormality (whether it is an amplifier abnormality or a transmission line abnormality) in the place where a supervisor is present when an abnormality occurs in a two-way CATV system. identification).

[Conventional technology]

Various devices (or methods) have been provided as devices (or methods) for centrally monitoring the operating status of a two-way CATV system at any -m locations.

For example, in JP-A-62-193394, there is a bidirectional CA
Detecting the operating status of each of the plurality of bidirectional amplifiers that are components of the TV system, and transmitting the identification data of the bidirectional amplifier to the monitor 911 (e.g., head end side) via a transmission line for display. discloses an example of a device that realizes centralized system monitoring.

[Problem to be solved by the invention]

In the above-mentioned device, the number detected as one of the physical quantities indicating the operating state includes not only the detection position (bidirectional amplifier) but also the shape of a leap from the previous stage detection position to the detection position! ! J (transmission line status) is reflected.

For example, as shown in FIG. 5, the detection signal of the upstream amplifier a12 includes the state of the upstream amplifier 12 and the bidirectional amplifier
2 and the state of the transmission line 92 between A1 and A1 are reflected.

Therefore, even if an abnormality is displayed between two-way amplifiers, the supervisor must check whether it is an abnormality in the two-way amplifier or whether it is possible to detect the problem from the previous detection position to the two-way amplifier. Is it an abnormality in the route (transmission line) leading to it?
Unidentifiable.

Therefore, in such cases, the repair 4m
They went to the site with materials and materials for transmission lines, and after workers manually identified the abnormality, they carried out repairs.

In other words, it took a long time to prepare the repair equipment and identify the abnormality, making it impossible to respond promptly.

The present invention is intended to solve these problems.

[Means and actions to solve the problem] Above! ! In order to solve the problem, the present invention takes the measures described in the claims.

That is, the upstream amplifier #I of two mutually adjacent bidirectional amplifiers
Using the A G C1 til J control voltages of the M and downlink booster sections, determine whether or not it is normal, and depending on the combination, determine whether the abnormality is occurring in the bidirectional amplifier, or It is identified whether it is the transmission line on the side of the two bidirectional amplifiers and displayed on the monitoring device.

〔Example〕

Examples of the present invention will be described below. (1) Overall system configuration (2) Bidirectional amplifier side (3) Supervisor i11! side 4) How to identify abnormal locations (5) Other examples I will explain in this order.

(1) Overall configuration of the system First, the overall configuration of the system according to this embodiment will be explained with reference to FIG.

In this bidirectional CATV system, television signals etc. from the receiving point T are sent to the transmission line 9 via the head end river, which is a head device, and a plurality of bidirectional amplifiers (AI, A2.・An.

), the attenuation of the signals (downlink television signal, downlink pilot signal Pd, etc.) on the transmission line 9 is compensated for and delivered to a terminal device (not shown) 11 such as a television receiver. The headend is equipment that sends the TV signals received by the antenna and signals from TV cameras, VTRs, etc., which are used as necessary, to the transmission path, and is used to transmit signals from receiving amplifiers, modulators, channel mixers, etc. configured.

On the other hand, from the terminal device side, upstream Pyro Cito 1! No.Pu
, upstream television signals, etc. are sent to the transmission line 9 and delivered to the headend while being compensated for attenuation on the transmission line 9 by a bidirectional amplifier in the same manner as described above.

Note that in the above, the transmission line 9 is generally constituted by a coaxial cable. Further, the frequency of the downlink pilot signal Pd is set to 450M)lz, and the frequency of the uplink pilot signal Pu is set to 48MHz.

In addition, each bidirectional amplifier (AI
, A2. 1Anl-), state signal generating means (3al, 3a2.+3an+), respectively.
+6) is built-in or attached, and the A of the upstream amplification section
The GC control voltage and the AGC control voltage of the downstream amplification section are each detected, and a state corresponding to the detected values is obtained! 31 +i signal S is generated and sent to the transmission line 9 at a predetermined timing (a predetermined timing different for each bidirectional amplifier) along with the identification data of the bidirectional amplifier concerned.

The status signal S sent to the transmission line 9 is then manually input to the signal processing unit 7 on the monitoring device side. The signal processing section 7 includes 211
It is composed of an 1I signal generating means 51 and an abnormal location specifying means 53. First, the above-mentioned B signal S is 2 +! 21a processing/processing is performed manually by the signal generating means 51, that is,
It is compared with a predetermined base value, which will be described later, and depending on the result, it is converted into a 21+I signal corresponding to normality or abnormality.

The binary status signal is then manually inputted to the abnormal location identifying means 53.

The abnormality location identification means 53 identifies two mutually adjacent bidirectional amplifiers (for example, Al and A2. A2 and A3. A3 and A
4°·) binary state signals (total of four binary state signals) are compared with the abnormal location identification table.

The abnormality location identification table is a table that associates matches of binary state signals with abnormality occurrence locations, as will be described later. As a result, when an abnormality occurs, it is determined whether the abnormality is occurring in the bidirectional amplifier or in the transmission line between the bidirectional amplifiers.

Based on the identification results thus obtained, the location where the abnormality has occurred is displayed on the monitoring device 7' installed near the head end.

In the above system, the 2M signal generating means 51 is placed on the monitoring device 7' side, but it may be placed on each bidirectional amplifier (AI, A2.., An, ...) side. In that case, a comparison result between the A G Cill WE voltage and a predetermined reference value, which will be described later, is sent to the transmission line 9.

(2) Bidirectional Amplifier Side Next, signal processing etc. on the bidirectional amplifier side will be explained with reference to FIGS. 2 and 3.

As shown, each bidirectional amplifier (A1.A2...A
n,...) has a downstream amplifying section (all, A21゜an
l,...), and upstream amplification section (A12.A22゜・
・+an2...) are installed respectively.

Each downlink amplification section includes a variable attenuator 301d, an amplification circuit 302d, and the like. The downlink pilot signal Pd appearing at the output of the amplifier circuit 302d is transmitted to the level detector 303.
After being detected at d, the AGC control circuit 304d is manually operated.
An AGC control voltage corresponding to the detection result is generated and input to the variable attenuator 30+d. In this way, the amplifier circuit 302d
AGC control is performed so that the level of the downlink pilot signal appearing at the output of the terminal becomes a constant value.

Similarly, each upstream amplification section includes a variable attenuator 301u and
It is composed of an amplifier circuit 302u and the like. Amplification circuit (9) 2
The uplink pilot signal Pu appearing at the output of u is detected by the level detector 303u, and then the AGC control circuit
An AGC control voltage corresponding to the detection result is generated and applied to the variable attenuator 301u. In this way, AGC control is performed so that the level of the uplink pilot signal appearing at the output of the convergence expansion vIJ 302u becomes a constant value.

In this system, the AGC control voltage is subjected to the following processing and sent to the transmission line 9 as a status signal S.

That is, the A G Ctill detected from the downstream amplification section
The control voltage SO1 and the AGC control voltage SU detected from the upstream amplifier section are together with an address signal (one word that functions as identification data for each bidirectional amplifier: SAI, SA2, etc.) from the address setting section 33b). , encoder 31
manually and converted into corresponding code data.

In this embodiment, the address data of each bidirectional amplifier will be explained as follows: Bidirectional amplifier A1...OOH Bidirectional amplifier A2...OIH Bidirectional amplifier A3...02H Bidirectional amplifier A4...03H. Here, 'H' is a code representing hexadecimal notation.

Next, the above-mentioned data (upward AGC control voltage data, downward AGC control voltage data, address data) encoded by the encoder 31 is modulated by the modulator 32 and made into a state signal S.

The status signal S is applied to the switch (SWI) of the bidirectional amplifier.
, SW2. While φSWn, . . . ) is closed, it is sent to the transmission line 9. The closing period of the switch is set differently for each bidirectional amplifier.

This sets the sending time of the status signal S to each bidirectional amplifier (A
I, A2.・・An, ・◆).

(3) Monitoring device side Next, signal processing and the like on the monitoring device side will be explained with reference to FIG.

Is there a supervisor near headend 1? 211 [signal generating means 51,
Also, an abnormality location specifying means 53 is installed.

As described in (2) above, the status signal S sent from each bidirectional amplifier to the transmission line 9 at different timings is first extracted by the duplexer 4 and divided into 2M
It is input to the If signal generating means 51.

Here, the 21IlI signal generation means 51 is a demodulator 51.
0, a decoder 515, a write controller 511, an upstream discrimination means (comparator) 512, and a downstream discrimination means (comparator) 513.

That is, 211! ! The state signal S manually inputted to the signal generating means 5I is first demodulated into code data by the demodulator W510, and then the decoder 515 compares the upstream AGC II control voltage Su and the downstream AGC control voltage S, and converts it into address data Sa. , decoded.

Next, the upstream A G Cf#I control voltage Su is applied to the comparator 512
In addition, the downstream AGC control voltage S comparator 513
Each signal is manually compared with a predetermined reference value, which will be described later, and converted into a binary state signal of "L" (low level) if higher than the reference value, and "H" (high level) if lower than the reference value. The above predetermined reference value is the lower limit value of the AGC control voltage when the AGC is operating normally, and is the lower limit value of the AGC control voltage when the AGC is operating normally.
The GC control voltage Su and the downlink AGC control voltage S ratio are set to different values. In addition, here, M L + “corresponds to the normal state (○), and u
It is assumed that Hn corresponds to an abnormal state (X).

On the other hand, the address signal S which is the identification data of the bidirectional amplifier
a manually inputs data to the write controller 5+1.

The write controller 511 is an IC that controls the write address of data to the memory 530, and the binary state signal is written to the address specified by the output from the write controller 511.

Next, reading data from the memory 530bS and the like will be explained.

The 21+1 data written as described above is stored in the memory 53 by data from the first read controller 538 and the second read controller 539 so that the data of the two bidirectional amplifiers adjacent to the FIJ are paired.
0h).

That is, as shown in the figure, the first a protrusion controller 538
The 7-trace data specified by the address specifying section 536 is output from the second read controller 53.
9 outputs address data having a value obtained by subtracting "1" from the address data by a subtracter 537.

For example, when the address data from the first read controller 538 is "04H" (the address where the data of the bidirectional amplifier A5 is registered), the address data of the second read controller 53ebl etc. is 03H.
'' (address where the data of bidirectional amplifier A4 is registered). As a result, bidirectional amplifier A5 and
Data from bidirectional amplifier A4 is read.

That is, the reading from the memo 1J530 is performed such that the binary data of two mutually adjacent bidirectional amplifiers are paired.

Note that the address specifying section 536 may be configured to generate numerical data that is automatically updated at predetermined closing intervals, or may be configured to generate numerical data that is specified by manual means such as a keyboard.

In the former case, at predetermined time intervals, the order of bidirectional amplifiers @
(A2 and AI, A3 and A2. A4 and A3.
), 21+l! Data is read. In addition, in the latter case, the 21 of the bidirectional amplifier specified on the keyboard
1iI data is read.

The binary data (total of four binary data, S1 to S4) read out from the memory 530 in this way is stored in the holding means 531.
~ 534 is held as an output to the abnormal location identification unit 535.

The abnormality location specifying unit 535 identifies the location where an abnormality has occurred by comparing the binary data with an abnormality location identification table (described later).

Based on the identification data, the display 7 of the monitoring device 7'
2, the abnormal location is displayed.

(4) Abnormal location identification method Next, an abnormal location identification method will be explained with reference to FIGS. 5 to 7 and the table.

In addition, in the following explanation, the M bidirectional amplifier is
This N bidirectional amplifier refers to a bidirectional amplifier that corresponds to address data from the first readout controller 538, and the N bidirectional amplifier refers to a bidirectional amplifier that corresponds to address data from the second readout controller 539. In Figure 5 etc., bidirectional amplification! ') When A2 is an M bidirectional amplifier, the bidirectional amplifier A1 becomes an N bidirectional amplifier.

In addition, in this embodiment, the abnormal whistle station identification unit 535 includes a control CPU 535a and a control CPU 535a, as shown in FIG.
R where the single 1m program of U 535a is stored
OM 535b, table ROM 535c storing the abnormality location identification table, and working RAM
535d.

As shown in the figure, binary data S1 to S4 are manually input to the control CPU 535a.

2M data S1 indicates the presence or absence of an abnormality in the AGC control voltage of the upstream amplification section of the installed N, and binary data s2 indicates the presence or absence of an abnormality in the AGC control voltage of the upstream amplification section of the installed N.
Indicates whether the GC control voltage is present or not, and 211! Data S3 indicates whether there is an abnormality in the AGC control voltage of the upstream amplifier section of the M, and binary data S4 indicates the presence or absence of an abnormality in the AGC control voltage of the upstream amplifier section of the M.
Indicates whether there is an abnormality in the ftFI control voltage.

Here, as described above, the 2fdl data Sl includes the state of the N uplink amplifier a12 and the bidirectional amplifier A2.
- The state of the transmission line 92 between 81 and 81 is reflected.

To be honest, 211m! An abnormality in the data St (in the case of "H", that is, x) means an abnormality in at least one of the N upstream amplifying section a12 and the transmission line 92.

Similarly, an abnormality in the 2111 data S2 corresponds to an abnormality in at least one of the N downlink amplifiers all and the transmission line 91. In addition, 211 [The abnormality in data S3 corresponds to an abnormality in at least one of the installed M upstream amplifying section a22 and the transmission line 93, and 21
This corresponds to an abnormality in at least one of the transmission line 21 and the transmission line 92.

Therefore, for example, 21I [data 51 and S4
If an abnormality occurs and the binary data S2 and the illusion are normal, it is determined that the transmission line 92 is abnormal and the location where the abnormality occurs is identified.

A summary of these relationships is the following ``abnormal location identification table 1'', which is stored as data in the table ROM 535c in FIG. 6.

Abnormal location identification table In this embodiment, an abnormal location is identified by referring to the above table with the binary data S1 to S4. Note that "next stage confirmation j" in the table refers to the address specification section 53.
6 is to prompt the operation to specify the address data of the amplifier in the latter stage of the installed M bidirectional amplifier, and r front stage confirmation 1 is to prompt the operation to specify the address data of the installed N bidirectional amplifier. .

The processing in the CP U 535a will be explained below.

As shown in FIG. 7, the CPU 535a, for example,
Processing starts when the power is turned on, and first the RAM53
Initial settings such as initialization of 5d are executed (Slot).

Next, manual processing of the data is executed (5103).The manual data is, for example, 2M data 51 to S4, and in this step, wait until four data 5l to 54 are collected.
The two data are stored in the memory 530 in correspondence with the address data designated by the address designating section 536 as described above.
The data is output from the CPU 535a and manually inputted to the CPU 535a.

In addition, in step 5105, it is determined where the abnormality has occurred by comparing the morning combination of the binary data S1 to S4 with the abnormality identification table.

As a result, if it is normal, the process advances to step Sill, and the signal to be output to the display controller 71 is "
Set normal signal j.

Additionally, if it is determined that there is an abnormality in the 5-stage M downstream amplification section,
r A signal j indicating that there is an abnormality in the M downstream amplifying section is set as a signal to be output to the display controller 71.

Steps 5115 to 5121 are also the same as step 5l11 above.
, or the same process as step 5113.

After that, the process returns to step 5103 and waits until the four pieces of data are collected again.

In this way, the location of the abnormality between the installed M bidirectional amplifier designated by the address designation unit 536 and the installed N bidirectional amplifier adjacent thereto is identified, and as a result, the output data set is Therefore, a display is performed on the display 72 by the display controller.

Note that the process shown in the seventh (!I) mainly indicates the abnormality location identification process, and the description of other processes will be omitted.

For example, when the address specifying section 536 automatically generates numerical data at predetermined time intervals, the process of controlling the numerical value is a process that controls the timing of generating the numerical data.

Further, the numerical data of the address designation 118536 may be sent to the display controller 1 and displayed on the display 72 together with the data indicating the location where the abnormality has occurred.

Note that there are various display methods on the display 72, such as a method that displays only the abnormal location, and a method that displays the difference between normality and abnormality (in the case of an abnormality, the location where the abnormality has occurred) for all bidirectional amplifiers. Although there are methods, these are well known and will be omitted here.

(5) IIl! Example of Next, other embodiments will be briefly described.

The above embodiment takes in the status signal S that is automatically transmitted from each bidirectional amplifier at different timings together with the identification data of the bidirectional amplifier, and converts it into binary data indicating the presence or absence of an abnormality. The system stores the data in a memory, reads the binary data of two adjacent bidirectional amplifiers from the memory as a pair, and compares the data with an abnormal location identification table to identify the abnormal location.
It is to be displayed.

However, instead of the above embodiment, the following configuration may be explored.

a) Instead of the determination using the abnormal location identification table, the determination may be performed using a logic circuit.

b) The status signal S may be sent from each bidirectional amplifier by polling from the monitoring room vi side.

Alternatively, the bidirectional amplifier to which the status signal S should be sent may be specified from the keyboard on the monitoring device side.

C) The modulation frequency of the state signal S may be made different for each bidirectional amplifier.

d) Binary data indicating the presence or absence of an abnormality may be generated on the bidirectional amplifier side.

〔Effect of the invention〕

According to the present invention, the monitor can determine whether the abnormality is occurring in which amplifier or in the transmission line between the amplifiers.

Therefore, the supervisor can save time and effort in preparing repair equipment and identifying the location where an abnormality has occurred, and has the advantage of being able to quickly respond to the occurrence of an abnormality.

Therefore, repair costs are reduced and user support is improved.

[Brief explanation of the drawing]

The figures explain the present invention in detail. Figure 1 is a block diagram showing the overall system configuration, Figure 2 is a block diagram showing the configuration of a bidirectional amplifier, and Figure 3 is a block diagram showing the configuration of a bidirectional amplifier. An explanatory diagram showing the method, Fig. 4 is a block diagram showing the circuit configuration on the monitoring device side, Fig. 5 is an explanatory diagram showing which part the status signal indicates, and Fig. 6 shows the configuration of the abnormal location identification section. The block diagram shown in FIG. 7 is the CPU 535 shown in FIG.
It is a flowchart which shows the process in a. At, A2. ” ,An,” ” ”Bidirectional amplifier,
9.9+. 92.92.・・・Transmission line, 51・ ・2 ++
i! Signal generation means, 53... Abnormal location identification means. 1 Gtsu0wa θsu■

Claims (1)

[Claims] A head device for sending multiple input signals to a transmission line, a transmission line that bidirectionally connects the head device and a terminal device, and an intervening line in the transmission line to compensate for attenuation of transmitted signals. bidirectional CA with multiple bidirectional amplifiers
In the TV system, the AGC control voltage of the upstream amplifier and the AGC control voltage of the downstream amplifier in each bidirectional amplifier are detected and compared with a predetermined reference value to generate a binary signal indicating normal or abnormal; A bidirectional CATV characterized in that, based on a combination of binary signals of two adjacent bidirectional amplifiers, a location where an abnormality occurs is specifically displayed as either one of the bidirectional amplifiers or a transmission line between the two bidirectional amplifiers.
How to determine the state of the system.