JPS62193394A - Status supervisory device for two way catv system - Google Patents

Abstract

PURPOSE:To supervise the state of operation of all amplifiers by outputting carrier signals that indicate the state of operation of each amplifier intermittently at the interval of cessation different at every amplifier from a carrier signal outputting device and displaying the state of operation of each amplifier by the state of operation display device based on outputted status signals. CONSTITUTION:In a two way CATV system, carrier signals are outputted from the status signal output device 30 provided in main line branch amplifiers 7A, 7B, 7C... for 1 [sec] at different time of cessation (51, 52, 53... {sec}), and the state of operation display device 71 in a center device 30 is operated responding to outputted carrier signals. Accordingly, the state of operation display device 71 receives carrier signals outputted from status signal output devices 30 of main line branch amplifiers 7A, 7B, 7C..., and demodulates them to be status signals, and it is enough to turn on and off the display section, and thereby, a circuit configuration becomes simple.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a bidirectional CA TV system that monitors the operating status of a bidirectional CA TV system, particularly the operating status of a plurality of bidirectional amplifiers provided on a transmission line. This article relates to a condition monitoring device for a TV system.

[Prior Art] In a bidirectional CATV system, if an abnormality occurs in the bidirectional amplifier's power supply installed on the transmission line and the bidirectional amplifier does not operate normally, the system cannot be operated properly. I won't be able to do it. Conventionally, bidirectional CATV systems monitor the operating status of bidirectional amplifiers, and when an abnormality occurs or is about to occur, a message to that effect is displayed and the abnormality is inspected.
Consideration is being given to installing condition monitoring equipment to prompt repairs.

That is, conventionally, each bidirectional amplifier constituting a bidirectional CATV system is provided with a status signal output device that sends a status signal representing its operating status onto a transmission line, and each of the status signals is transmitted to any point on the transmission line. The idea is to create a status monitoring device that can constantly monitor the operating status of the system by providing an operating status display device that detects the operating status of each amplifier based on the status signal output from the output device and displays that fact. It is being

Conventionally, this type of status monitoring device has the following methods: ■ The status signals output from the status signal output device of each bidirectional amplifier are modulated at different frequencies and output, and these signals are filtered in the operating status display device. A status monitoring device configured to extract each status signal by demultiplexing and demodulating it and displaying the operating status of each bidirectional amplifier; A status monitoring device using a so-called polling method, which operates a desired status signal output device by outputting a detection command signal, receives the status signal output from the status signal output device with an operating status display device, and displays the status. , It has been known.

[Problems to be Solved by the Invention] However, in the above condition monitoring device (①), since each condition signal output device outputs a condition signal modulated at a different frequency, the television signal and various information signals flowing through the transmission line are In addition to the signal transmission bands such as the above, it is necessary to occupy a wide frequency band for transmitting each state signal, and there is a problem that the frequency utilization efficiency of the transmission line is poor. In particular, in a large-scale bidirectional CATV system in which dozens of bidirectional amplifiers are used, the frequency band for status signal transmission becomes too wide, making it difficult to implement. Further, in the operating state display device, it is necessary to separate the state signals from each state signal output device for each frequency, and there is a problem that a large number of filters are required for this purpose, making it expensive. Furthermore, each status signal output device requires a modulator with a different frequency, making it impossible to maximize production.

On the other hand, in the status signal monitoring device mentioned above, since each status signal output device is operated individually to output the status signal, the status signals are not output from each status signal output device at the same time. Although the frequencies can be made the same and there is no problem like the one mentioned above, it is necessary to install a control device and a transmitter for polling in the operating status display device, making the circuit configuration complicated. There is always the problem that it becomes

Therefore, the present invention is capable of outputting a status signal modulated at the same frequency from the status signal output device provided in each bidirectional amplifier, and displaying the operating status well without polling on the display device side. The purpose of the present invention was to provide a state monitoring device for a bidirectional CATV system configured to enable the following.

[Means for Solving the Problems] That is, the configuration of the present invention as a means for solving the above problems is, for example, as shown in FIG. A plurality of bidirectional amplifiers A1.
A2. A bidirectional CATV system status monitoring device for monitoring the operating status of a bidirectional CATV system comprising each of the bidirectional amplifiers A1. A2. . . . respectively, an operating state detection means M1 detects a predetermined operating state of the amplifier A1 (or A2. a discriminating means M2 for discriminating whether or not the state is normal; and according to the discriminating result of the discriminating means M2, the amplifier
or Δ2. . The modulated carrier signal is transferred to the transmission line 1
- Carrier signal sending means M that sends out intermittently for a certain period of time
5, and a demodulating means M7 for demodulating the carrier signal sent out from the carrier signal sending means M5 at any point on the transmission line; Based on the demodulated state signal, the discrimination result of the discrimination means M2 is detected, and each of the bidirectional amplifiers A1
．． A2. A display means M8 for displaying the operating state of the amplifiers Δ1, . A2. The gist of the present invention is a state monitoring device for a two-way CATV system, which is characterized by being set to a different value for each time.

[Operation] In the status monitoring device for the bidirectional CA TV system of the present invention configured as described above, first, each bidirectional amplifier A1
．． A2. . . . The status signal output device M6 is set for each
Then, the operating state of the bidirectional amplifier A1 (or △2...) detected by the operating state detecting means M1 is determined by the discriminating means M2.
It is determined whether or not it is normal, and a status signal corresponding to the result is output from the status signal generating means M3. The status signal from the status signal generating means M3 is transmitted to the operating status display device M9 via the transmission line.
4, the modulated carrier signal is modulated into a carrier signal of a predetermined frequency by the carrier signal sending means M51. s and others are sent out to the transmission line. Note that each status signal output device M6 outputs a carrier signal modulated at a predetermined frequency, and in the present invention, the carrier signal is outputted from each carrier signal transmitting means M5.
Since the status signals are output intermittently for a certain period of time at different pause intervals set in advance, the probability that the status signals are output at the same time is small and does not pose a practical problem (this pause interval will be explained in detail later). .

On the other hand, in the operating state display device M9, the demodulation means M7 demodulates the carrier signal of a predetermined frequency output from each of the state signal output devices M6, and the display means M8 detects each of the signals based on the demodulated state signals. direction amplifier A1. A
2. The operating status of... will be displayed.

Here, the operating state of the bidirectional amplifier detected by the operating state detecting means M1 is, for example, the output level of the amplifier circuit (
(A, G, C, levels may be used), the power supply voltage supplied to the amplifier circuit, the sealed state of the amplifier housing, etc. The operating state detecting means M1 for detecting this operating state may be any device that can electrically detect the various operating states mentioned above. For example, when detecting the output level of an amplifier circuit, a detector may be used in a sealed housing. A switch may be used to detect the state.

Further, the determining means M2 is for determining whether the various detected operating states are normal or not, and for example, compares the detection signal from the operating state detecting means M1 with a preset reference voltage. You can configure it to do so.

Further, the status signal generating means M3 may be configured to output a digital signal representing the status according to the determination result of the determining means M2, and can be easily realized by using, for example, a microphone computer or the like. The status signal outputted from the status signal generating means M3 indicates the detected part in order to be able to determine which part of which amplifier is abnormal when displaying the operating state by the operating state display means M9. Of course, it is necessary to add data representing the corresponding amplifier to a3<.

Next, the carrier signal output pause time in the carrier signal sending means M5 is such that when carrier signals are simultaneously output from each status signal output device, each signal influences each other and becomes noise, which causes the status signal to be displayed on the display device. Since the signals cannot be transmitted, it is only necessary to reduce the probability of simultaneous output, and this may be set in advance as shown below, or may be set using random numbers in each carrier signal sending means M5.

When the carrier signal output pause time is set in advance, the bidirectional amplifier A1. A2. . . , the carrier signal output time from each status signal output device is 1 [sec], and the pause time is N [sec], and the bidirectional amplifier A1. A2
．． The collision avoidance probability F (M, N> is the following formula % formula %) to avoid simultaneous output of carrier signals from ... Just set it so that it's close to you.

That is, for example, if the collision avoidance probability is 0%, the limit value of the downtime (limit downtime > NL is 0 = 1- (1/ (
From Nl +1))2XMPzNL=iH-1, it is determined as shown in ■ in the following table. However, the collision avoidance rate needs to be 85% or higher for practical purposes, so it should be at least the value shown in ■ in the following table calculated from 0.85=1-('1/(NL+1>)2X P2) It is hoped that

Table (Unit: sec>) Also, if the collision avoidance probability is set to a pause time of 85%,
The time required for the collision avoidance probability to reach 100% is as follows:
The values are as shown in ■ in the table above.

In other words, outputting the carrier signal twice is 97.8%, 0.85 +
(1-0,85) xo, 85 = 99.9...% with 0.9783 outputs, 0.978+(1-0,978> Xo, 978=0.
999... Because of this, the time required to output the carrier signal three or more times becomes the 100% avoidance time shown in Table 3 above.

The practical downtime indicated by ■ in the above table indicates the carrier signal sending down time of the carrier signal sending means M5 with the shortest downtime, and for other carrier signal sending means, add 1 or 2 to each value above. .3...The value obtained by adding [sec] may be set. In addition, the above estimate is based on the carrier signal sending time
[sec], so if the transmission time is n [sec], the above numerical value may be multiplied by 0.

[Example" Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the bidirectional CATV system of this embodiment.

In the figure, 1 receives a TV signal, etc. and misses! I! The transmission signal output from the head end 1 is sent to the terminal side via the center device 3.

Also, on the trunk line 5 from the center device 3 to the terminal side, there are trunk branch amplifiers 7A, 7B, 7 that bidirectionally amplify the transmission signal flowing through the trunk line 5 and branch to the terminal side of each region.
C, . . . are arranged, and each trunk branch amplifier 7A, 7B,
7C,... are equipped with turnouts 8A, 88.8C,..., respectively.
・Power supply devices 9A, 9B,
9C,... are provided.

Here, first, each of the main line branch amplifiers 7A and 7B.

7C, . . ., as shown in FIG. Main upstream amplification circuit 13 that amplifies the waved upstream transmission signal
, and a trunk downstream amplifier circuit 14 that amplifies the downstream transmission signal branched by the branching circuit 12, and a branch circuit 16 provided on the *♀ line.
and the head end 1 branched by this branch circuit 16.
A branch amplifier circuit 17 that amplifies and outputs the transmission signal from the side to the terminal T side of each home or tM facility via the branch line 5a, the distributor SP, the branch DC, etc. is drawn, 9♀
The transmission signal flowing through the line 5 is bidirectionally amplified, and the transmission signal from the head end 1 side is amplified and outputted to the branch line 5a side.

Also, each main line branch amplifier 7A, 78.7G.

. . ., each of the above power supply devices 9A, 9B, 9C.

...supplied via *♀ wire 5, for example AC 3
Power supply separation filter 21 that extracts the power supply voltage of 0 [V]
Then, this extracted power supply voltage is rectified and converted into, for example, DC 2
A constant voltage circuit 22 for converting to a DC voltage of 4 [V] is provided to operate each of the above-mentioned amplifier circuits.

Furthermore, each of the trunk branch amplifiers 7A, 7B, and 7C.

... is equipped with a status signal output device 30 that detects whether each of the above-mentioned amplifier circuits etc. is operating normally and outputs a status signal representing the operating status.

This status signal output device 30 includes the Q♀ ridgeline amplifier circuit 13
．． A of the 9♀ line downstream amplifier circuit 14 and branch amplifier circuit 17
GC level, DC voltage level from constant voltage circuit 22,
Alternatively, the AC voltage level from the power supply devices 9A, 9B, 9C, . . . extracted by the power separation filter 21,
By detecting each of them and determining whether each detection level is higher than a predetermined level, it is determined whether the amplifier is operating normally, and the q♀ line branch amplifier 7A,
7B.

Detects the tightening state of the lid of the housing (hereinafter referred to as housing lid) in which 7C, ... is housed, determines whether the inside of the housing is sealed, and outputs the determination result as, for example, an 8-bit status signal. a status signal generation circuit 31 configured using a microcomputer;
A state signal consisting of an 8-bit digital signal outputted from the state signal generation circuit 31 is output from 0. The FSK modulation circuit 32 converts the frequency to, for example, 5KHz or 7KHz in accordance with the frequency of the FSK modulation circuit 32, and FM modulates the status signal output from the FSK modulation circuit 32 to a carrier signal of, for example, 45MHz in order to transmit it on the q♀ line. FM modulation circuit 33
, a gate circuit 34 that outputs the status signal modulated into a 45MH2 carrier signal by the FM modulation circuit 33 onto the main line 5 for 1 [sec], and an opening/closing period of this gate circuit 34, that is, a pause time for outputting the carrier signal. a pulse generating circuit 35 for controlling, and a branch circuit 36 provided on the 9♀ line 5.
The data can be transmitted to the center device 3 via.

Note that between the pulse generators 114 of the pulse generator circuit 35,
For example, 51. ．． 52.53. - Set to a value different from [sec], the gate circuit 34 generates a pulse generator 35
The state signal is output for only 1 [sec] according to the signal from. Also, the status signal output bag @30
In order to detect the tightening state of the housing lid, a switch 38 with one end grounded is installed (pull), which is turned on when the housing lid is detected.

Next, the state signal generating circuit 31 is constructed as shown in FIG.

In other words, the status signal generation circuit 31 includes each of the above-mentioned amplifier circuits 13.1.
Detection circuits 41 to 4 that detect the output level from 4.17
3, a rectifier circuit 44 that rectifies the AC voltage extracted by the power separation filter 21, and a DC voltage from the constant voltage circuit 22, which applies the DC voltage to the switch 38, and limits the current flowing through the switch 38 when the switch 38 is turned on. Current limiting resistor R1
and buffer circuits 45 to 50 which input the detection voltages from the detection circuits 41 to 43, the rectification circuit 44, the constant voltage circuit 22, and the switch 38, and the detection voltages inputted through the respective buffer circuits 45 to 50. A multiplexer 51 that selects and inputs the control signal according to the control signal, and an A/D that converts the detected voltage input via the multiplexer 51 into a digital signal.
A converter 52 and a detection signal A/D converted by this A/D converter 52 are input, and a multiplexer 51
Based on the input/output port 53 that outputs a control signal to the A/D converter 52 and the detection signal inputted through the input/output port 53, it is determined whether the operating state of the Q♀ line branch amplifier is normal or not. A process that makes a judgment and generates a status signal according to the judgment result, [! lj et al. CP that executes status signal generation processing
U54 and ROM55 in which the data and control programs necessary for executing the status signal generation process in the CPU54 are stored in advance, and the data necessary for executing the status signal generation circuit in the CPU54 are temporarily stored. The RAM 56 is read and written to the FS according to control signals from the CPU 54.
Output ports 1 to 57 that output status signals to the K modulation circuit 32
, path line 5B connecting the above parts, and CP L, J
54, and a clock circuit 59 which outputs a clock signal at a predetermined period.

Further, in the status signal generation circuit 31 configured in this way,
The status signal is output from the output port 57 to the FSK modulation circuit 32 by the operation of the CPU 54. In this embodiment, the status signal generation process is executed as shown in FIG. It is designed to output an 8-bit status signal representing the status of each part. This status signal generation process will be explained below along the flowchart shown in FIG.

The 8-bit various status signals outputted from the output port 57 through this status signal generation process include amplifier identification data representing the amplifier in question, and a detection portion representing the operating state of which part of the amplifier the status signal indicates. It is composed of identification data and status data indicating whether or not its operating state is normal, and is set in the ROM 55 in advance.

As shown in the figure, when the process starts, first step 101
is executed, a control signal is output to the multiplexer 51 and the A/D converter 52, and the detection circuit 41 and the buffer 1 circuit 4
AGC of 9♀ line up amplifier circuit 13 inputted via 5
The level (hereinafter referred to as trunk upstream AGC level) Val is read, and the process moves to step 102. In step 102, it is determined whether the main upstream amplifying circuit 13 is operating normally by determining whether or not the read mainline upstream AGC level ■a1 is equal to or higher than the reference value VaO.

If Val≧VaO and it is determined that the main upstream amplifier circuit 13 is operating normally, the next step 103 is performed.
3-bit trunk upstream output normal data indicating that fact is read from the ROM 55 and output to the FSK modulator 32 via the output port 57. On the other hand, if Va1<VaO and it is determined that the main upstream amplification circuit 13 is not operating normally, the process moves to step 104. and step 10
At step 4, 8-bit trunk downlink output abnormality data representing this fact is read from the ROM 55 and output to the output capo-1 via 57 to the FSK modulator 32.

In this way, the operation state of the main uplink amplifier circuit 13 is expressed by the operations in steps 101 to 104 described above.
When the upstream line output normal (or abnormal) data is output,
The following step 105 is executed, and it is then determined whether a predetermined period of time (50 [m5ec] in this embodiment) has elapsed. This process is repeatedly executed until 50 [m5ec] have elapsed, and when 5Q [m5ec] has elapsed, the process moves to the next step 106.

In step 106, similarly to step 101, the AGC level Vbl of the main downlink amplifier circuit 14 input via the detection circuit 42 and buffer 1 circuit 46 is read, and the process proceeds to step 107. Then, in step 107, the read AGC level Vb1 and reference level VbO are
If Vbl≧VbO, it is determined that the main downlink amplifier circuit 14 is operating normally, and in the next step 108, the main downlink output normal data is output.
If this is necessary for VbO, it is determined that an abnormality has occurred in the trunk downlink amplifier circuit 14, and in the next step 109, trunk downlink output abnormality data is output.

Next, in step 110, similarly to step 105, it is determined whether a predetermined time (50 m5ec) has elapsed. Then, in step 110, 50 [m5ec]
If it is determined that the elapsed time has elapsed, the process proceeds to step 111, in which the ΔGC level VC of the branch amplifier circuit 17 inputted via the detection circuit 43 and the buffer circuit 47 (51) is detected.
1 and moves to step 112.

In step 112, the AGC level MC read above is
A comparison is made between I and the %i% level VCO. And M
If CI≧VCO, it is determined that the branch amplifier circuit 17 is operating normally, and in the next step 113, branch output normal data is output, and if Vcl<VcO, an abnormality has occurred in the branch amplifier circuit 17. [14]
Outputs branch output abnormal data.

When the branch output normal (or abnormal) data is output in this way, step 115 is executed. In step 115, as in step 105 or step 110, it is determined whether a predetermined time (50 [m5ec]) has elapsed.
When 0 [m5ec] has elapsed, the process moves to the next step 116. Then, in step 116, the power supply separation filter 2 is input via the rectifier circuit 44 and the buffer circuit 48.
AC voltage level from 1 to each power supply device 9A mentioned above.
, 9B, 9G, . . . and moves to step 117.

In Step 1]7, it is determined whether the power supply devices 9△, 98.9C, etc. are operating normally by comparing the read AC voltage level old and the standard voltage level VdO. , if V old ≧ VdO, power supply device normal data is output in step 118, and if V old is VdO, power supply device abnormal data is output in step 119.

Next, in step 120, as in step 115 above, it is determined whether a predetermined time (50 [m5ec]) has elapsed.
When 50 [m5ec] have elapsed, the process moves to the next step 121. In step 121, the DC voltage level ■e1 from the constant voltage circuit 22 inputted via the buffer 749 is read, and the process moves to the next step 122 to determine whether the DC voltage level Ve1 becomes equal to or higher than Ir t<=voltage level VeO. Decide whether or not. This process is a process for determining whether or not the constant voltage circuit 22 is operating normally.
If el≧VeO, it is determined that the constant voltage circuit 22 is normal, and the process moves to step 123, where constant voltage circuit normal data is output; if not, constant voltage circuit abnormal data is output in step 124. Output.

In this way, the operating state of each of the above parts is detected by its output (voltage) level, it is determined whether the state is normal or not, and data representing that is outputted, Step 1
After confirming that the predetermined time (50 [m5cc]) has elapsed in step 25, the switch 38 is turned on in step 126.
The voltage level f1 occurring at one end of is read. In this process, the DC voltage from the constant voltage circuit 22 is applied to one end of the switch 38 via the current limiting resistor Ri, and if this switch is in the OFF state, the voltage level will be lower than that of the constant voltage circuit 22. On the other hand, when the switch is turned on, the voltage level becomes the ground potential, that is, the rOJ level, so that the switch 38 is in the 0N-OFF state, that is, the housing lid is sealed. is being detected.

Next, in step 127, it is determined whether the voltage level v[1 of the switch 3B read in step 126 is O[V]. If the result is f1-○, it is determined that the switch 38 is in the ON state and the housing lid is not sealed, and the process moves to step 128, where lid tightening abnormality data is output.

Conversely, if Vfl>O, the switch 38 is in the OFF state, and it is determined that the tightening of the lid is normal, and the process moves to step 129, where normal lid tightening data is output.

When the process of step 128 or 129 is completed, the following step 130 is executed for a predetermined period of time (50[
m5ec] ), the process moves to step 101.

By executing the abnormal signal generation process as described above, the status signal output from the abnormal signal generating circuit 31 is switched to 50 [m5ec] fTJ and 300 [m5ec] fTJ.
m5ec] as one cycle, all the status signals representing the above-mentioned parts are output. Therefore, in this embodiment, the state signal output device provided in each *all-line branch amplifier 7A, 78.7C, . . .
．． 53. Since the carrier signal is output for 1 [sec] at =-[sec], at least 3 state signals representing the operating states of the above-mentioned parts are output at each output timing.
This will be output more than once.

Next, FIG. 6 is a block diagram showing the configuration of the center device 3. As shown in FIG. As shown in the figure, the center device 3 of this embodiment includes the above-mentioned q♀ line branch amplifiers 7A and 7B.

7C, ..., a branch DC, or a distributor SP, and an image data output device 70 that outputs various information, image data, etc. to be transmitted to the terminal side, and each trunk branch amplifier 7A, 7B. , 7C, . . . is provided with an operating state display device 71 that displays the operating state of each section in response to a carrier signal from the state signal generating device 30 provided at each of the sections.

Incidentally, image data from the image data output device 70 and carrier signals from each status signal generation device 30 are inputted and outputted onto the main line 5 via a branching circuit 72 and a branching circuit 73.

The operating state display device 71 displays each trunk branch amplifier 7A, 7B.
, 7G, . . . and display sections 8'lA, 81B, 81C, . The FM demodulation circuit 82 demodulates the FM modulated carrier signal output from the state signal generation circuit 30, the FSK demodulation circuit 83 demodulates the demodulated state signal into an 8-bit digital signal, and the FSK demodulation circuit 83. Each amplifier 7A extracts one state signal from the demodulated 8-bit state signal.

A plurality of decoders 84A, 84B, 84C, . . . provided corresponding to 7B, 7C, . . . and a decoder 84A.
, 848.84G, . . . display circuits 85A, 85B, 85G, .

Here, the decoders 84A, 84B, 84C, . . . extract only the state signals corresponding to the respective amplifiers 7A, 7B, 7C, . From the extracted status signals, 12 types of status signals such as all-line upstream output normal data and mainline upstream output abnormality data outputted from the status signal generation circuit 31 are further extracted and outputted from the corresponding output terminals. It is designed to output an h-level output signal.

The display circuits 85A, 858.85C, . . . are set and reset by output signals from the two output terminals of the decoders 84A, 84B, 84C, .
latch circuits 1 to 6 and 2f[ of latch circuit L1
i! It consists of an OR circuit OR1 connected to the input terminal of d, and a timer circuit T1 that is reset when the output terminal of this OR circuit OR1 becomes a trigger level. The two input terminals of each latch circuit, 1 to L6, are located behind the output terminals of each decoder 84A, 84B, 84C, . It is connected to two output terminals that output mutually contradictory data representing the operating status of the q♀ line branch amplifiers 7A, 7B, and 7G, such as lid tightening normal data and lid tightening abnormal data. When the data is normal, an output signal of l-ow level is output, and when the data is abnormal, an output signal of l-1i gh' level is output. Further, the OR circuit OR1 and the timer circuit GO1 are connected to the latch circuit L1 from the decoder to the 1-1
i C1i) level signal is not input for a long time,
Since it is considered that the relevant status signal generating device 30 is not operating normally, the condition, that is, the signal generating device 3
In this embodiment, timer circuit lower 1 is configured as a 10-minute timer, and an output signal of +-t r Q h level is output from OR circuit OR 1 for 10 minutes or more. The timer circuit T1 outputs a signal of -1iQh level when the timer circuit T1 is not activated.

Furthermore, the display sections 81A, 818, 81C, . . . are composed of seven LEDs that emit light based on high level signals outputted from the timer circuit T1 and the latch circuits L1 to L6, respectively. Main branch amplifier 7A, 7
B, 7C, . . . When the operating state of each part is abnormal, a message to that effect can be displayed. In other words, in this embodiment, the display sections 81A, 81B, 81C, . . .
13, main downstream amplifier circuit] 4, main branch amplifier circuit] 7, constant voltage circuit 22, power supply device 9△ (or 9B, 9C...), housing lid crying state,
It is designed to display an abnormality in the status signal output device 30.

In the bidirectional CA-V system of this embodiment configured as described above, each *♀ line branch amplifier 7A, 7B.

From the status signal output device 30 provided in 7G,...
Each has a different body stop time (51, 52, 53, ... [
A carrier signal is output for 1 [sec1] at
The operating state display device @71 in the center device 30 is operated in accordance with the outputted carrier signal. Therefore, in the operating state display device 71, each trunk branch amplifier 7A, 7B
, 7C, . . . , receives the carrier signal output from the status signal output device 30, demodulates it as a status signal, and makes the display section blink on and off according to the status signal. It becomes easy.

Furthermore, since each status signal generator 30 outputs a carrier signal of 1 [sec] with different pause times, the probability that each carrier signal is transmitted redundantly onto the main line 5 is small, and system operation For the above problem, 4 guns. In other words, for example, in a CATV system equipped with 20 trunk branch amplifiers,
The output pause time of the carrier signal of each status signal output device 30 is 5
1.52. ...70 [SeC], all carrier signals are 1 per status signal output device Plf30.
[Since the output is performed three times in 1 sec, the probability of avoiding duplication is 99.9% at 170 [sec], which does not pose any problem in system operation, as shown in the table in J-E above.

Furthermore, in this embodiment, the circuit configuration of the status signal generating device 30 includes amplifiers 7Δ, 7B, and 7G.

. . . The pulse generating circuit 3 determines the pause time for each
5 and ROM 55 are different from each other, but can be constructed using the same components, and early production can be achieved. In other words, it is necessary to input data representing the operating status of each part corresponding to each amplifier into the ROM 55.
In addition, since the pulse generation circuit 35 needs to set the rest time of the carrier signal to different values, it is necessary to use different parts for each amplifier, but all other parts use the same part. This makes it possible to achieve premature birth.

In the above embodiment, the 9♀ gland 5 from each status signal generator
Although the upper carrier signal output pause time is determined using the pulse generation circuit 35, the interval may be determined using random numbers using the CPU 54 inside the status signal generation circuit. In this case, the status signal output device provided for each trunk amplifier can be further standardized, and the speed of production can be improved.

Further, in the above embodiment, each trunk branch amplifier 7A.

Power supply device 9 provided for 7B, 7C,...
The operating status of A, 9B, 9C... is configured to be detected from the AC voltage level 1q by the power supply separation filter 21, but in recent years, this type of power supply device 9A, 9B, 9C... Since uninterruptible power supplies equipped with batteries are often used, in such cases the operating status of each power supply device is detected and the I
It is also possible to provide a status signal output device that generates the I&' transmission signal. In other words, for example, detecting power outage status in each region from the commercial power supplied to each power supply device,
If the battery voltage of the power supply device drops during a power outage, the system will no longer be able to operate, so by detecting that voltage level, it becomes possible to more broadly grasp the operating status of the entire bidirectional CATV system. This makes it possible to expand its range of use.

[Effects of the Invention] In the bidirectional CATV system status monitoring device of the present invention described in detail above, a carrier signal representing the operating status of each bidirectional amplifier is output from the carrier signal pressure device provided in each bidirectional amplifier. Since each amplifier can be output intermittently at different pause intervals, and the operating status of each amplifier can be displayed on the operating status display device based on the output status signal, the operating status of all amplifiers can be constantly monitored. You will be able to do this. Furthermore, since a large number of operating states to be detected can be set for each bidirectional amplifier, it is possible to improve the monitoring capability and to monitor the entire system over a wide range of areas. Furthermore, in the present invention, since the state signal frequency from the state signal output device installed in each bidirectional amplifier can be made the same, the modulation means of each state signal output device can be standardized, and mass production thereof is facilitated. Furthermore, the status display means does not need to perform a polling operation, but only needs to receive status signals from each status signal output device and display the operating status according to the status signals. , the circuit configuration becomes simple.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 6 show an embodiment of the present invention, FIG. 2 is a schematic diagram showing the entire bidirectional CATV system, and FIG. FIG. 4 is a block diagram showing the circuit configuration of the main branch amplifier; FIG. 4 is a sub-block diagram showing the state signal generation circuit; FIG. 5 is a flowchart showing the state signal generation processing executed in the state signal generation circuit; FIG. 6 is a block diagram showing the circuit configuration of the operating state display device provided inside the pink device. Ml... Operating state detection means M2... Discrimination means M3... Status signal generation means M4... Modulation means M5... Carrier signal sending means M6, 30... Status signal output device M7... Demodulation means M8...Display means M9, 71...Operating status display device [-1A...Head end

Claims (1)

[Claims] A bidirectional CATV system status monitoring device that monitors the operating status of a bidirectional CATV system that includes a plurality of bidirectional amplifiers on a transmission line from a head end to a terminal, Each of the amplifiers has an operating state detecting means for detecting a predetermined operating state of the amplifier, and a determining means for determining whether or not the detected state is normal based on the detection result of the operating state detecting means. , a state signal generating means for generating a state signal corresponding to the amplifier according to a determination result of the determining means; and a modulating means for modulating the state signal generated by the state signal generating means into a carrier signal of a predetermined frequency. , carrier signal transmitting means for intermittently transmitting the carrier signal modulated by the modulating means to the transmission line for a certain period of time, and a status signal output device consisting of: demodulating means for demodulating the carrier signal sent out from the carrier signal sending means; and detecting the determination result of the determining means based on the status signal demodulated by the demodulating means, and displaying the operating status of each of the bidirectional amplifiers. A two-way CATV system, characterized in that: an operating status display device comprising: a display means; and a carrier signal sending pause time of the carrier signal sending means is set to a different value for each of the amplifiers. condition monitoring equipment.