JPH01126885A - Monitoring method and converter device for catv system - Google Patents

Abstract

PURPOSE:To economically monitor a transmission path from the branching and distributing output terminal of a relay amplifier to the converters of respective subscriber's homes by providing an incoming/outgoing transmission level monitoring function in the converter generally used in a city type CATV. CONSTITUTION:A monitoring unit 20 is added to the ordinary converter disposed in the subscriber's home 47 and a transmission path monitoring equipment 60 suitably shared by a converter controller 50 is provided on a center equipment 41. Then, the output deciding whether it is normal or not as for the level of an outgoing transmission signal is returned from the converter to the center equipment 41 and as for the level of an outgoing transmission signal, the actual receiving level of a carrier from the converter is detected at the center equipment 41, thus by executing a polling for monitoring the transmission path to the respective converters, the transmitting state of the incoming and outgoing signals is monitored. Thereby, the transmission path can be economically and effectively monitored as a whole of a CATV system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a two-way urban CATV system, and more particularly to a method for monitoring a CATV system and a converter device therefor, which enables monitoring of the transmission level state thereof. It is something.

[Prior art] Conventional two-way urban CATV systems, for example,
It is configured as shown in the figure, and transmits transmission signals including video signals, data signals, etc. transmitted from a sending center device 41 such as a head end or a video center via a trunk line 42 via a bidirectional relay amplifier 43. , branching from main line 42.
It is distributed to the distribution line 44, further led to a drop-in line 46 via a tap-off, that is, a directional coupler 45, and further from the drop-in line 46 to the CATV converter 4 in the subscriber's home 47.
8, where it is converted into a signal suitable for a television receiver 49, and the signal is supplied to the television receiver 49.

In FIG. 3, reference numeral 50 denotes a converter management device that can communicate bidirectionally with the converter 48, and makes calls such as polling to the converter 48 in each subscriber's home 47 to check the usage status of each subscriber, such as viewing and listening. Collect time data and print out weekly and monthly reports regarding billing data.

Figure 4 shows a modified example of the configuration in Figure 3, where:
To monitor the status of these relay amplifiers and also to perform reverse switching when a CATV system becomes complicated and large and a large number of relay amplifiers are used. For this purpose, in a CATV network similar to that shown in FIG. 3, a monitoring unit 51 is built into each relay amplifier 43, and the voltage level, signal slope, or 8C or DC voltage of a signal at a predetermined portion of each relay amplifier 43 is monitored. To detect. On the other hand, the center device 41 is provided with a relay amplifier monitoring device 52 that polls each monitoring unit 51 to monitor the operational status of each relay amplifier 43. In addition, the monitoring device 52 remotely controls the reverse switch in the relay amplifier 43, searches for the relay amplifier address, and prints out the results of the operation status as a weekly or monthly report.

Further, the above-mentioned converter 4B is configured as shown in FIG. 5, for example. That is, in FIG.
1 is a converter output terminal connected to the lead-in line 46; 2
3 is a signal distribution/mixer, 3 is a demodulator that receives the signal distributed from the signal distribution/mixer 2 and demodulates the data signal from the center device 41, and 4 is a signal from this converter to the center device 4.
1 modulates the data signal sent to signal distribution/mixer 2
It is a modulator that supplies A control device 5 processes the data signal from the demodulator 3, processes the data signal supplied to the modulator 4, or controls each part of the converter, and can be composed of a CPU or the like. 6 is a channel selection switch, 7 is a remote control transmitter for channel selection, and 8 is a signal distribution/mixing device tuned to the frequency of the channel of the center device 4I selected by the channel selection switch 6 or remote control transmitter 7. This is an electronic tuner section that detects the scrambled video signal from the device 2. A descrambler section 9 reproduces the original video signal from the signal detected by the electronic tuner section 8. 10 is a converter output terminal for supplying the original video signal taken out from the descrambler section 9 to the television receiver 49.

L Problems to be Solved by the Invention J In the conventional monitoring system as shown in FIG. 3 or 4, only the relay amplifier 43 is monitored.
The subsequent state of the branch/distribution system 44 and the wiring system inside the subscriber's home 47 cannot be monitored. Therefore, it is not known until a subscriber complains about poor television reception that an abnormality has occurred in the transmission path from the branch/distribution output terminal of the relay amplifier 44 to the subscriber's in-house wiring system. In this way, conventionally, it has not been possible to monitor abnormalities in the transmission path downstream of the branching/distribution system on the transmission side such as the head end or the video center 41, and this has caused information to be disseminated for a fee, such as in urban CATV. This was a big problem for the system that supplies it.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to provide a converter in a subscriber's premises with an appropriate transmission path monitoring function, and to transmit the monitoring results to the transmitting side.
ATVATV system method is provided.

Another object of the present invention is to provide a converter device for use at a subscriber's home, which is appropriately equipped with transmission line monitoring means for carrying out the method of the present invention.

[Means for Solving the Problems] In order to achieve such an object, the method of the present invention bidirectionally couples a center device and a plurality of converters via a transmission line (ATV system). In response to polling from the center device, the plurality of converters form a monitoring data signal regarding the level of the downlink transmission signal transmitted from the center device to each of the plurality of converters, and transmit the monitoring data signal to the plurality of converters. The data is transmitted from each of the converters to the center device, and the center device monitors the transmission status of the downlink transmission signal on the transmission line based on the transmitted monitoring data signal.

Another form of the method of the present invention is a CAT system in which a center device and a plurality of converters are coupled in a bidirectional manner via a transmission line.
In the VATV system, in response to polling from the center device, multiple converters send predetermined uplink transmission monitoring signals to the center device, and the center device responds to the predetermined uplink transmission monitoring signals that have been transmitted. It is characterized in that the transmission status of uplink transmission signals on the transmission path is monitored based on the transmission path.

In order to achieve the above object, the device of the present invention provides a CATVA system that is bidirectionally coupled to a center device via a transmission path.
In a TV system converter device, means for forming a monitoring data signal regarding the level of a predetermined downlink transmission signal from the center device in response to polling from the center device, and sending the formed monitoring data signal toward the center device. It is characterized by comprising a means to do so.

Another embodiment of the device of the present invention is a CATV ATV system converter device bidirectionally coupled to a center device via a transmission line, in which a predetermined uplink transmission monitoring signal is generated in response to polling from the center device. and means for sending an uplink transmission monitoring signal toward the center device.

[Function] In the present invention, the converter device in the subscriber's premises monitors downlink transmission signals in response to polling from the center device, reports the results to the center device, and monitors uplink transmission signals from the converter device. Since a predetermined signal is sent to the center device and its reception status is monitored, such monitoring can be performed using the control device and signal distribution/mixer provided in a normal converter. Therefore, only a small number of circuits are required to be added to the converter device, and the center device only needs to poll the monitoring circuit in the converter device using the CPU in the normal converter management device. C including the converter device or center device in the customer's home
For the ATV system as a whole, transmission paths can be monitored economically and effectively.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

An embodiment of the present invention is shown in FIG. Here, the same parts as in FIGS. 3 and 5 are given the same reference numerals.

In FIG. 1, reference numeral 20 indicates a monitoring unit added to a converter 48 provided in a subscriber's premises 47. In FIG. This monitoring unit 20 is activated by polling from a transmission line monitoring device 60 provided in the center device 41, and detects a predetermined downlink transmission signal such as a pilot signal from the signal distributed from the signal distribution/mixer 2. , a downlink signal detection/A/
It has a D conversion section 21. The digital signal is transferred to the control device 5.
Here, the signal is converted into a signal to be sent to the center device 41, and then sent back from the terminal 1 to the center device 41 via the modulator 4 and the signal distribution/mixer 2.

Similarly to the converter management device 50, the center device 41 is controlled by the CPU to poll each converter 48 in each subscriber's home 47, and receives the downlink transmission signal from the monitoring unit 20 described above. A transmission line monitoring device 60 is provided that requests return of a signal indicating the level state. This transmission path monitoring device 60, like the converter management device 50, has a CPt161° keyboard 62. External storage device 63, such as a fixed disk unit. It is configured using output devices such as a printer 64 and a display 65 and a high frequency modem 66.

Here, it is preferable that this monitoring device 60 and the converter management device 50 share hardware and are configured integrally, and a software program for controlling the CP[l is provided separately.

As described above, in the center device 41, the polling request for the monitoring status report of the signal level of the downlink transmission signal from the transmission line monitoring device 60 to the converter device is sent from the keyboard 6.
Instruct from 2. In response to the polling, data regarding downlink transmission signals returned from each converter device is collected in this monitoring device 60, and the data is collected in the external storage device 6.
3, display it on the display 65, and if necessary print it out using the printer 64.
The state of the transmission level of the downlink signal can be monitored on the center device 41 side.

Reference numeral 22 denotes an upstream signal oscillation circuit that oscillates a carrier at a specific frequency within the upstream signal band, that is, a specific frequency that is previously assigned to the subscriber from the center device 41 side.

23 is an upstream signal level setting circuit, and the oscillation circuit 22 oscillates the carrier at the level set by this setting circuit 23, and supplies the control device 5 with a data signal indicating the set level. As a result, the control device 5 transmits the data indicating the transmission level of the carrier as an upstream signal from the converter device from the modulator 4 via the signal distribution/mixer 2, together with the carrier output from the oscillation circuit 22. The signal is sent to the device 41.

On the side of the center device 41, the transmission path monitoring device 60 uses the CPU 61 to calculate the level of the carrier signal demodulated via the high-frequency modem 66, and also calculates the level of the carrier signal from the converter device based on the transmitted data signal. The state of the transmission path is determined by reading the level and comparing the above-described calculated carrier level with the set level. The data regarding the transmission path collected in this way is stored in the external storage device 63, displayed on the display 65, and, if necessary, printed out by the printer 64, so that the center device 41 can output the downlink signal. Enables monitoring of transmission level status.

In this way, in this embodiment, the normal converter 48 includes
In addition to adding a monitoring unit 20 as shown in the first diagram,
The center device 41 is only provided with a transmission path monitoring device 60, which is preferably configured in common with the converter management device 50, and the monitoring device 60 polls each converter device for transmission path monitoring. , the transmission status of uplink and downlink signals can be monitored.

FIG. 2 shows an embodiment of the present invention in which the configuration is more simplified when monitoring with lower precision than in the case of FIG. 1 is required. In this embodiment, the transmission path on the center device 41 side is the monitoring device 6.
0 has almost the same configuration as in the case of FIG. 1, and the monitoring unit 3
0 is composed of a downstream signal level determination circuit 31 and an upstream signal oscillation circuit 32.

As in the case of FIG. 1, the transmission line monitoring device 60h's provided in the center device 41 is activated by polling, and a predetermined signal such as a pilot signal is transmitted from the signal distributed from the signal distributor/mixer 2. The downlink transmission signal is detected by the downlink signal level determination circuit 31, and based on the detection output, it is determined whether the level of the downlink transmission signal is normal or abnormal. The judgment output is supplied to the control device 5, where it is converted into a signal to be sent to the center device 41, and then the modulator 4
The signal is then sent back from the terminal 1 to the center device 41 via the signal distributor/mixer 2.

The upstream signal oscillation circuit 32 oscillates a carrier at a specific frequency within the upstream signal band, that is, a specific frequency previously assigned to the subscriber from the center device 41 side. In this oscillation circuit 32, oscillation is started by turning on the power of the oscillation circuit 32 or opening the output gate by the control device 5 in response to polling from the transmission path monitoring device 60.
The obtained oscillation carrier is sent out to the center device 41 via the signal distributor/mixer 2. In response to polling, the transmission path monitoring device 60 detects the level of the transmitted carrier as described above, and detects the level of the carrier transmitted as described above.
The upstream transmission level is compared with a pre-specified transmission level to monitor the status of the upstream transmission level.

As described above, in this embodiment, only the determination output as to whether the level of the downlink transmission signal is normal or not is sent back from the converter device to the center device 41, and the level of the uplink transmission signal is determined from the carrier output from the converter device. By detecting the actual reception level at the center device 41, the monitoring device 60 polls each converter device for transmission path monitoring, thereby making it possible to monitor the transmission status of uplink and downlink signals.

[Effects of the Invention] As is clear from the above, according to the present invention, downlink transmission signals are monitored in the converter device in the subscriber's premises in response to polling from the center device, and the results are reported to the center device. , and for upstream transmission signals, by sending a predetermined signal from the converter device to the center device and monitoring the reception status, it is possible to transmit not only the relay amplifier but also all upstream/downstream signals from the main line to the branch/distribution system downstream. The transmission status of the transmission path can be monitored.

In addition, the present invention allows such monitoring to be performed using the control device and signal splitter/mixer provided in a conventional converter, and requires only a small amount of circuitry to be added to the converter device for this purpose. In the center device,
Since it is only necessary to poll the monitoring circuit in the converter using CPt1 in the normal converter management device, it is economical for the entire CATV system including the converter in the subscriber's premises or the center device. Therefore, the transmission path can be monitored effectively and effectively.

Therefore, in the present invention, the converter normally used in urban CATV is provided with an uplink/downlink transmission level monitoring function. The transmission path to the converter device in a person's home can be monitored economically.
As a result, it is possible to exhibit excellent effects in advance prediction of failures and immediate response to emergency maintenance, which are the most worrying issues for CATV system operators.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing one embodiment of the present invention, Fig. 2 is a block diagram showing another embodiment of the invention, and Fig. 3 is a system showing an urban CATV system together with an example of its transmission line monitoring system. 4 is a system diagram showing an urban CATV system together with other examples of its transmission line monitoring system, and FIG. 5 is a block diagram showing an example of a normal CATV converter. DESCRIPTION OF SYMBOLS 1... Converter output terminal, 2... Signal distribution/mixer, 3... Demodulator, 4... Modulator, 5... Control device, 6... Tuning switch, 7. ... Tuning remote control transmitter, 8... Electronic tuner section, 9... Descrambler section, 10... Converter output terminal, 20... Monitoring unit, 21... Down signal detection/A/D Conversion unit, 22... Upstream signal oscillation circuit, 23... Upstream signal level setting circuit, 30... Monitoring unit, 31... Downstream signal level determination circuit, 32... Upstream signal oscillation circuit, 41. ...Center device, 42...Main line, 43...Bidirectional relay amplifier, 44...Branch/distribution line, 45...Directional coupler, 19゛46...Leading line, 47... Subscriber's home, 48... Converter, 49... Television receiver, 50... Converter management device, 51... Monitoring unit, 52... Monitoring device, BO... Transmission path monitoring device, 61 ...CPU. 62...Keyboard, 63...External storage device, 64...Printer, 65...Display, 66...High frequency modem. Patent Applicant Sumitomo Electric Industries Co., Ltd. Representative Patent Attorney Yoshi Tani - Ordinary beach β funeral (: ATV Koshihi' - Evening Ida 1's BuD riff Figure 5)

Claims (1)

[Claims] 1) In a CATV system in which a center device and a plurality of converters are coupled in a bidirectional manner via a transmission line, in response to polling from the center device, the plurality of converters: forming a monitoring data signal regarding the level of a downstream transmission signal transmitted from the center device to each of the plurality of converters; transmitting the monitoring data signal from each of the plurality of converters to the center device; A method for monitoring a CATV system, characterized in that a center device monitors a transmission state of a downlink transmission signal on the transmission path using the transmitted monitoring data signal. 2) In a CATV system in which a center device and a plurality of converters are coupled in a bidirectional manner via a transmission line, in response to polling from the center device, the plurality of converters connect to the center device. , a predetermined uplink transmission monitoring signal is sent out, and the center device monitors the transmission status of the uplink transmission signal on the transmission path based on the transmitted predetermined uplink transmission monitoring signal. How to monitor CATV systems. 3) In a converter device of a CATV system that is bidirectionally coupled to a center device via a transmission line, monitoring the level of a predetermined downlink transmission signal from the center device in response to polling from the center device. A converter device for a CATV system, comprising: means for forming a data signal; and means for sending the formed monitoring data signal toward the center device. 4) In a converter device for a CATV system that is bidirectionally coupled to a center device via a transmission path, means for generating a predetermined uplink transmission monitoring signal in response to polling from the center device; A converter device for a CATV system, comprising means for sending a transmission monitoring signal toward the center device.