JPH1075434A - Data communication quality monitor system and its device in catv transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily grasp a fault in a transmission line by monitoring data communication quality between a center and an optional position of the transmission line at the center. SOLUTION: A center is provided with a center equipment A and data signal return devices B1-Bn are arranged to an optional position of a transmission line E, the center equipment A sends check data, and the data signal return devices B1-Bn, which designate a data signal return device to return the check data, receive the check data returned from the designated data signal return device via an incoming channel, monitor the data communication quality, return the check data sent from the center equipment and received to the center equipment via the incoming channel when the device is designated by the center equipment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system and an apparatus for monitoring data communication quality between a center and an arbitrary position in a CATV system.

[0002]

2. Description of the Related Art Hitherto, a bidirectional C capable of transmitting a video signal and a data signal from a head end to a consumer side and a data signal from a consumer side to a head end side by frequency multiplex division.
ATV transmission systems are known.

[0003]

However, in such a CATV transmission system, the data signal transmitted from the customer side to the head end side must be transmitted in the form of a tree-like network or modulated to a high frequency. In addition, since transmission is performed from a large number of consumers toward the head end, there is an effect of communication failure due to ingress noise and distortion of a multi-channel high-frequency signal. In addition, when an error occurs in a data signal, it is not known whether the cause is the data itself or the transmission path, and to identify the cause of the transmission path, go to the source consumer and send the data signal. Then, the data signal must be received at the center side, and the data signal before transmission from the transmission source must be compared with the data signal after reception at the center. In particular, in the low uplink channel,
There is a problem that a large amount of phase distortion occurs and the values of 0 and 1 of the data signal change to other values. Further, in the uplink channel, as described above, since transmission terminals of a large number of consumers are connected, ingress noise increases and data signals are disturbed. The influence of the phase distortion and the ingress noise on data communication increases as the distance from the center increases. Therefore, a center is expected to realize a method that can easily measure the communication quality of data transmission between the center and an arbitrary position on a transmission line.

Accordingly, it is an object of the present invention, in view of the above problems, to enable the center to monitor the communication quality of a transmission line between a center and an arbitrary position, thereby facilitating the grasp of a transmission line failure.

[0005]

Means for Solving the Problems To solve the above problems, a system according to claim 1 can be adopted. As shown in FIG. 1, this system monitors the data communication quality of an upstream band transmission line between a center of a bidirectional CATV system having an upstream channel and a downstream channel and an arbitrary position of a transmission line E at the center. In the system, a center device A is provided at a center, and data signal return devices B1 to Bn are provided at arbitrary positions of a transmission path E.
The center device A transmits inspection data for monitoring data communication quality and address data designating a data signal returning device requesting the return of the inspection data, and transmits the inspection data returned via a predetermined uplink channel. A device for receiving and monitoring data communication quality, and a data signal returning device B
1 to Bn are characterized in that when their own device is designated by the center device by the address data, the device returns the test data transmitted and received from the center device on a predetermined uplink channel.

As shown in FIG. 1, the center device A according to claim 2 includes a data generation means X1 for generating inspection data for monitoring data communication quality, and an arbitrary return position of a data signal on a transmission line. A position designation means X3 for designation;
A data transmitting unit X4 for transmitting the inspection data generated by the data generating unit X1 and address data specifying the position specified by the position specifying unit X3 to a predetermined downlink channel; Designation means X
Communication quality monitoring means X5 for receiving inspection data returned from the position designated by 3 and monitoring data communication quality
And characterized in that:

[0007] A data signal returning device B1 to Bn according to claim 3
As shown in FIG. 1, the demodulation means Y1 receives a signal from a predetermined downlink channel and demodulates address data, and determines whether the address data demodulated by the demodulation means Y1 is data designating its own device. The address determination means Y2 for determining whether or not the test data is transmitted, and when the own apparatus is designated by the address determination means Y2, the test data transmitted on the downlink channel of the transmission path E is frequency-converted into a predetermined uplink channel and transmitted. And a data transmission means Y4 for transmitting the data to the path E.

[0008] The data signal return device B1 ~ Bn of claim 4
As shown in FIG. 2, the demodulator Y1 receives a signal from a predetermined downlink channel and demodulates address data and test data, and the address data demodulated by the demodulator Y1 designates its own device. Address determining means Y2 for determining whether or not the received data is obtained, modulating means Y3 for modulating the test data demodulated by the demodulating means Y1 into a data signal of a predetermined uplink channel, and a self-device designated by the address determining means Y2. In this case, the data signal modulated by the modulation means Y3 is transmitted through a transmission path E through a predetermined uplink channel.
And data transmission means Y4 for transmitting the data to

In order to solve the above-mentioned problem, a system according to claim 5 can be employed. As shown in FIG. 3, this system monitors the data communication quality of an upstream band transmission line between a center of a bidirectional CATV system having an upstream channel and a downstream channel and an arbitrary position of a transmission line E at the center. System
A center device A is provided at a center, and data signal return devices B1 to Bn are provided at arbitrary positions. The center device A sends address data designating a data signal return device requesting return of inspection data, and Is a device that receives the inspection data returned via the uplink channel and monitors the data communication quality, and the data signal return devices B1 to Bn, when their own device is designated by the address data by the center, The apparatus is characterized in that it is an apparatus for returning stored test data for monitoring data communication quality through a predetermined uplink channel.

As shown in FIG. 3, the center device A according to claim 6 has a data storage means X 6 for storing inspection data for monitoring data communication quality, and an arbitrary return position of inspection data on a transmission line. A position designation means X3 for designation;
Return data designating means X7 for designating inspection data requested to be transmitted on a predetermined uplink channel; data transmission means X4 for transmitting address data for specifying a position designated by the position specifying means X3 to a predetermined downlink channel; Communication quality monitoring means X5 for receiving inspection data transmitted from a position designated by the position designation means X3 via a predetermined uplink channel of the transmission path E and monitoring data communication quality.

[0011] A data signal returning device B1 to Bn according to claim 7
As shown in FIG. 3, a data storage means Y5 for storing inspection data for monitoring data communication quality, a demodulation means Y1 for receiving a signal from a predetermined downlink channel and demodulating address data, Address determining means Y2 for determining whether the address data demodulated by the means Y1 is data designating the own device, and address determining means Y2
And a data transmission means Y4 for transmitting the inspection data stored in the data storage means Y5 to the transmission path E through a predetermined uplink channel when the own device is designated by the following.

Further, the system according to claim 8 can be adopted. As shown in FIG. 4, the center device A of the system according to claim 1 or 5 also transmits channel identification data specifying an uplink channel to which test data is returned, This is a device that receives the test data returned via the designated uplink channel and monitors the data communication quality, and the data signal return devices B1 to Bn return the test data on the designated uplink channel designated by the channel identification data. The device is characterized in that:

As shown in FIG. 4, the center device according to claim 9 is the center device according to claim 2 or 6, further comprising channel designation means X 2 for designating an arbitrary upstream channel to be monitored. The data transmitting means X4 is a data transmitting means X4 for transmitting channel identification data unique to the channel specified by the channel specifying means X2 to a predetermined downstream channel, and transmits the upstream channel specified by the channel specifying means X2 of the transmission path E. Communication quality monitoring means X5 for receiving inspection data transmitted from the position designated by the position designation means X3 via the control means and monitoring data communication quality.

According to a tenth aspect of the present invention, in the data signal returning apparatus of the third, fourth or seventh aspect, the demodulating means X1 is a demodulating means for demodulating channel identification data. X4 is a data transmitting means for transmitting the inspection data to the transmission path on the upstream channel corresponding to the channel identification data demodulated by the demodulating means X1.

The center device according to claim 11 is the center device according to claim 2 or claim 9, wherein the data transmission means X4
Is characterized in that test data and other data are transmitted on separate predetermined downlink channels.

A system according to a twelfth aspect of the present invention can be adopted. As shown in FIG. 5, in the system according to the fifth aspect, the inspection data is sent from a center device and a data signal returning device is provided. Is written.

The center device according to a thirteenth aspect of the present invention is the center device according to the sixth aspect, wherein the data communication quality monitoring is performed for initial setting of inspection data for monitoring the data communication quality, as schematically shown in FIG. Setting means X8 for sending test data for writing and write command data to a predetermined downlink channel and writing the test data to a data signal returning device arranged at an arbitrary position for sending test data.
Is provided.

A data signal returning device according to claim 14
In the data signal returning apparatus according to claim 7, n has initial setting means Y6 for storing the inspection data sent from the center apparatus in the data storage means Y5 as an initial setting, as schematically shown in FIG. It is characterized by.

[0019]

According to a first aspect of the present invention, there is provided a system in which a center device is provided at a center of a bidirectional CATV system, and a data signal returning device is provided at an arbitrary position on a transmission line. Sends inspection data for quality monitoring and address data designating a data signal returning device requesting the return of the inspection data, and receives inspection data returned via a predetermined uplink channel to improve data communication quality. The data signal returning device is a device that, when its own device is specified by the address data by the center device, returns the test data transmitted from the center device and received on a predetermined uplink channel. . As a result, the inspection data is transmitted from the center device and received by the data signal returning device, and the inspection data is returned from the designated data signal returning device to the center device via a predetermined uplink channel. By the way, the data transmitted on the downlink channel has a very low probability that the communication quality will be worse than the data transmitted on the uplink channel. As a result, the communication quality of the upstream band transmission line between the center and an arbitrary position of the transmission line can be monitored by the center device based on the inspection data returned from the data signal returning device.

In the center device of the present invention, the data generating means generates inspection data for monitoring data communication quality, and the position specifying means specifies an arbitrary return position of the data signal on the transmission line. Then, the test data and address data for specifying the return position of the test data are transmitted to a predetermined downlink channel by the data transmitting means. Then, the communication quality monitoring means receives the inspection data returned from the designated position via a predetermined uplink channel and monitors the data communication quality. In this way, test data is generated,
By transmitting the test data and receiving the test data returned from the designated position via a predetermined uplink channel and monitoring the data communication quality, the probability that the data communication quality deteriorates on the downlink transmission path is extremely high. Therefore, it is possible to monitor the data communication quality of the upstream band transmission path.

According to a third aspect of the present invention, when the self-device is designated by the address data, the data signal returning device converts the frequency of the test data transmitted from the center device to a predetermined uplink channel by the data transmitting means and transmits the data. To the road. As described above, by using the data transmission unit that converts the test data transmitted from the center without demodulation and returns the data on the uplink channel, it is possible to change the transmission quality by various modulation methods to the data signal return device. It can be measured without.

According to a fourth aspect of the present invention, when the self-device is designated by the address data, the demodulating means demodulates the test data, and the modulating means re-modulates the demodulated test data once. The test data re-modulated to a predetermined uplink channel by the transmission means is transmitted to the transmission path. In this way, using the means for demodulating the test data sent from the center once, re-modulating it and returning it on the uplink channel, even if the data signal is deteriorated on the downlink transmission line, the bit is inverted. As long as the data does not deteriorate, the original data can be restored by demodulating the data. As a result, the inspection data is not affected by the downlink transmission path, and only the data communication quality of the uplink transmission path can be monitored.

The system according to claim 5 is a system in which a center device is provided at a center of a bidirectional CATV system, and a data signal returning device is provided at an arbitrary position.
A device for sending address data designating a data signal return device requesting return of test data, receiving the return test data via a predetermined uplink channel, and monitoring data communication quality, the data signal return device Is a device that returns stored test data for monitoring data communication quality through a predetermined uplink channel when its own device is designated by the center by address data.

According to a sixth aspect of the present invention, the center device stores the test data by the data storage means, specifies an arbitrary return position of the test data on the transmission line by the position specifying means, and sets the return data specifying means on a predetermined uplink channel. Specify the inspection data requested to be sent. The data transmission means sends address data specifying the return position of the test data to a predetermined downlink channel, and the communication quality monitoring means sends the test data transmitted from the position specified via the predetermined uplink channel of the transmission path. To monitor the data communication quality.

According to a seventh aspect of the present invention, the data signal returning device stores the inspection data in the data storage means, and when the self-device is specified by the address data, the inspection data stored in the data transmission means is transmitted to the predetermined upstream. The data is transmitted to the transmission path via a channel. According to the invention of claims 5, 6, and 7,
By storing the test data in the data signal returning device and transmitting the stored test data on a predetermined uplink channel, only the data communication quality in the uplink band can be monitored.

In the system according to the eighth aspect, in the system according to the first or fifth aspect, the center device also transmits channel identification data designating the uplink channel to which the inspection data is returned, and returns the channel identification data via the designated uplink channel. A device that receives the test data obtained and monitors the data communication quality, and a data signal returning device is a device that returns the test data on the uplink channel specified by the channel identification data.

A center device according to a ninth aspect of the present invention is the center device according to the second or sixth aspect, wherein an arbitrary upstream channel to be monitored is designated by the channel designation means, and a unique channel is specified for the channel designated by the data transmission means. The channel identification data is also transmitted to a predetermined downlink channel, and the inspection data transmitted from the specified position via the uplink channel specified by the communication quality monitoring means is received to monitor the data communication quality.

According to a tenth aspect of the present invention, in the data signal returning apparatus of the third, fourth or seventh aspect, the inspection data is transmitted by the data transmitting means on an upstream channel corresponding to the channel identification data. To send to.
According to the eighth, ninth, and tenth aspects of the present invention, the uplink channel for returning the inspection data can be designated by the center device, and the data communication quality of any uplink channel on the uplink bandwidth transmission line can be monitored.

According to the eleventh aspect of the present invention, in the center apparatus of the second or ninth aspect, the data transmission means transmits the test data and the other data through a predetermined downlink channel separate from the test data. As a result, the test data and the other data can be transmitted using different modulation schemes and transmission rates, and it is not necessary to change the data signal return device even when the modulation scheme or transmission rate of the test data is changed.

A system according to a twelfth aspect is the system according to the fifth aspect, wherein the inspection data is transmitted from the center device.
It can be written to a data signal return device.

According to a thirteenth aspect of the present invention, in the center device according to the sixth aspect, inspection data and a write command are transmitted to a predetermined downlink channel by the initial setting means X8, and the inspection data is arranged at an arbitrary position. Inspection data is written to a data signal returning device for transmitting the data.

According to a fourteenth aspect of the present invention, in the data signal returning apparatus of the seventh aspect, the inspection data transmitted from the center device is stored in the data storage means Y5 as initial settings by the initial setting means. Claims 12 and 1
According to the inventions of 3 and 14, the inspection data stored in the data signal returning device is initialized by the center device from the center device.
Since writing is possible, the inspection data can be changed as needed.

The data signal returning device of the present invention is a device for transmitting test data to the upstream band transmission line by the above-mentioned predetermined means, and is provided at a plurality of arbitrary positions on the CATV transmission line. For example, it is inserted at an arbitrary position of a coaxial cable, or is disposed in a relay amplifier, a consumer terminal, or a tuner of the consumer terminal.

The center device of the present invention instructs the above-mentioned predetermined means to transmit the inspection data from the data signal returning device, receives the inspection data returned from the data signal returning device on the uplink channel, This is a device for obtaining a bit error rate, a CN ratio, and the like using the returned data and monitoring data communication quality.

The data communication quality monitoring system of the present invention comprises:
A data signal returning device for returning test data on an uplink channel by a predetermined means is inserted into any of a plurality of positions on the transmission path, a monitoring position is designated, and the data is transmitted from the designated position via the uplink channel. This is a system configured by a center device that receives inspection data and monitors data communication quality at the center using the inspection data. However, the upstream channel for transmitting data may be a predetermined channel or specified by the center. Therefore, by using the system of the present invention, the center can monitor the data communication quality of the upstream band transmission line between the center and an arbitrary position of the transmission line. Therefore,
The cause of the failure and the recovery from the failure can be quickly and easily performed.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described with reference to specific examples. First, a first embodiment will be described. FIG.
FIG. 1 is a diagram illustrating an entire configuration of an ATV system. A transmission line E composed of a coaxial cable is provided from the head end C. The transmission path E is provided with a plurality of bidirectional relay amplifiers (D1 to Dn). This transmission path E
Is a transmission line based on the frequency division multiplex transmission system. In the head end C, the video signal and data signal of the independent broadcast and the TV broadcast are transmitted to the transmission line E using the downstream channel via the mixer (MIXER). In the customer terminal F1, a data signal is transmitted to the transmission line E by the data terminal Z1 using an uplink channel.

The channel arrangement on the transmission line E is configured as shown in FIG. The upstream channel is arranged in the low group, and the downstream channel is arranged in the high group. Uplink channels are control channels for data transmission of channels chLc1 to chLc3, and channels chL1 to ch for video signal transmission.
M channel of Lm, downlink channel is channel chHc1
There are provided control channels for data transmission of channels chHc3 to chHc3 and n channels of channels chH1 to chHn for video signal transmission. In this embodiment, the downlink channel c
hHc1 to chHc3 are channels for transmitting data signals, and uplink channels chLc1 to chLc3 are channels for monitoring communication quality.

A center device A is provided at the head end C. Also, at an arbitrary position on the transmission path, that is, inserted into the transmission path E, the data signal returning device is inserted into the relay amplifiers (D1 to Dn), the consumer terminal F1, the tuner of the consumer terminal F1, or the like. (B1 to Bn) are provided.

The center device A is configured as shown in FIG. An address setter 46 for designating a unique address assigned to the data signal returning device and a data setter 48 for setting inspection data for monitoring communication quality are connected to the CPU 41 via an input interface 49.
The CPU 41 sends the address data set by the address setting device 46 and the inspection data set by the data setting device 48 via the output interface 44 to the data modulator 4.
5 is provided. The output of the data modulator 45 is connected to an input / output terminal 51 via a splitter 52, from which address data and test data are output as data signals to a predetermined downstream channel of the transmission path E. The CPU 41 has a ROM 42 storing a program 421 for controlling data transmission and a program 422 for monitoring communication quality, and a position storing a correspondence between an address and a position where the data signal returning device is provided on the transmission line. The RAM 43 in which the information storage area 431 is formed is connected. When the address is designated by the address setting unit 46, the position designation means is operated by the data setting unit 48.
The data generation means is implemented by setting the inspection data in. Further, according to a program 421 for controlling data transmission, data is output to the data modulator 45 by the CPU 41, and an output of the data modulator 45 is output to a predetermined downlink channel of the transmission path E via the input / output terminal 51. As a result, data transmission means is implemented.

The demodulator 53 for demodulating the data signal of the upstream channel of the transmission line E is transmitted via the demultiplexer 52 to the transmission line E.
Via an input / output terminal 51. Further, the demodulator 53 is connected to the CPU 4 via the input interface 49.
1 connected. Further, using the inspection data set by the data setting unit 48 and the inspection data demodulated by the demodulator 53, the CPU 41 performs data processing by the communication quality monitoring program 422 incorporated in the ROM 42, The processing result is output from the communication quality output device 50 via the output interface 44 as a data communication quality such as a bit error rate. Using the inspection data returned on the uplink channel and demodulated by the demodulator 53, the communication quality monitoring program 422 causes the CPU 41 to monitor the data communication quality, thereby implementing the communication quality monitoring means.

The control data transmitted from the center device A is configured as shown in FIG. That is, it is composed of address data for specifying the data signal returning device, command data for giving an operation command to the data signal returning device, and inspection data for monitoring communication quality.

The data signal returning devices B1 to Bn are configured as shown in FIG. The transmission line E has an input terminal 29 and an output terminal 30. The input terminal 29 and the output terminal 30 are connected to power separation filters 70 and 71. The high-frequency signal from the transmission path E is split by the splitter 31, passes through the splitter 32, and is split by the splitter 33. One of the divided signals is input to a data demodulator 25, and the other signal is input to a channel converter 26. The data demodulator 25 is a device (demodulation means) for demodulating a data signal output from the center device A to a predetermined downlink channel. The data demodulated by the data demodulator 25 is read by the CPU 21 via the input / output interface 24.

The channel converter 26 is a device that converts the test data output from the center device A to a predetermined downstream channel into a predetermined upstream channel. The inspection data frequency-converted by the channel converter 26 is supplied to the amplifier 27
And amplified. The test data, which has been frequency-converted into a predetermined upstream channel and further amplified, is output via the output switch 72 (analog switch) to the splitter 3.
2. The signal is transmitted to the input terminal 29 via the branching device 31. By outputting the inspection data to the transmission path E through the input terminal 29, the data transmission means is implemented.

The CPU 21 stores a ROM 22 storing a control program for returning the test data sent on a predetermined downlink channel to a predetermined uplink channel, and a unique address assigned to the data signal returning device. In which the self address storage area 231 is formed
23 are connected.

Next, the operation of this system will be described with reference to the flowchart of FIG.
The operation procedure of the CPU 21 of the data signal returning device will be described with reference to a flowchart in FIG. The operator specifies the return position of the data signal by operating the address setting unit 46 in the center device A to specify the address of the data signal return device inserted into the transmission path E. Further, the data setting device 48 is operated to set the inspection data.

In step 100, the address setting unit 46
Is read (position specifying means), and in step 102, the inspection data set by the data setting device 48 is read (data generating means).
Next, in step 104, control data in a format as shown in FIG. 8 is created and output to the data modulator 45 via the output interface 44. Data modulator 4
5 modulates a high-frequency carrier with the control data and sends out the modulated data from the input / output terminal 51 to a predetermined downlink channel of the transmission path E (data sending means). That is, according to the control data transmitted to the predetermined downlink channel in step 104, the check data is returned from the addressed data signal return device on the uplink channel.

The test data returned from the addressed data signal return device on the upstream channel is transmitted to the demodulator 5
3 demodulated. The demodulated data is input to the CPU 41 via the input interface 49. In step 106, the test data demodulated by the demodulator 53 is read. Next, step 10
In step 8, the communication quality is measured by the communication quality monitoring program 422 using the inspection data read in step 102 and the inspection data read in step 106.
That is, the communication quality is measured by comparing the received test data with the original test data transmitted by the center device and measuring the ratio of the changed bits of the binary data to all the bits. Next, in step 110, the measured communication quality is visualized using the position information in the position information storage area 431, and output as data communication quality by the communication quality output device 50 via the output interface 44.
That is, the communication quality monitoring means is implemented by steps 106 to 110.

As a result, in the center device A, the operator can monitor the communication quality of the upstream band transmission line between the center and an arbitrary position of the transmission line E. Address setting device 4
The communication quality between the center of the upstream band transmission line and the transmission line can be monitored by sequentially changing the address data set in No. 6. Further, the inspection data set by the data setting unit 48 and the communication quality monitoring program 422
The method of measuring the data communication quality can be changed by changing the contents.

In the data signal return devices B 1 to Bn, the control data transmitted on the downstream channel of the transmission path E is demodulated by the data demodulator 25. Then, in step 200, this control data is read via the input / output interface 24. Next, step 202
, The address data of the received control data is R
It is determined whether the address matches the self address stored in the self address storage area 231 of the AM 23 (address determining means).

If the address data of the control data does not match the self address, the output switch 72 is turned off in step 204, and the transmission line E and the amplifier 27 are isolated. Then, returning to step 200, if the address data of the control data does not match the self address, that is, if the self device is not specified,
The output switch 72 continues to be turned off.

If the address data of the control data matches the self address, the output switch 72 is turned on at step 206, and the output of the amplifier 27 is connected to the transmission line E. As a result, the test data distributed by the distributor 33, frequency-converted to a predetermined uplink channel by the channel converter 26, and further amplified by the amplifier 27 are:
The signal passes through the output switch 72, the duplexer 32, and the splitter 31, and is sent to the transmission line E (data sending means). As a result, the inspection data sent from the center device to the transmission path E is returned to the center device A from the specified data signal return device via the predetermined uplink channel.

By returning the test data after demodulation without demodulation, the data signal returning device does not need to change anything even if the modulation method of the test data is changed. The device may be changed according to the modulation method. Therefore, it is possible to easily compare transmission errors due to a plurality of data modulation methods.

In the above embodiment, the data transmitted from the center device A may be configured as shown in FIG. That is, one piece of control data is composed of address data for designating the data signal returning device and command data for giving an operation command to the data signal returning device as one control data, and inspection data for monitoring communication quality. Then, these control data are transmitted through separate channels as described in claim 11. By transmitting the test data and the other data on different channels, the modulation scheme and transmission rate of the test data and the other data can be different. As a result, even if the modulation method and transmission rate of the test data are changed, simply add a modulator and demodulator corresponding to the new modulation method and transmission rate to the center device.
The data signal return device can respond without any changes.

Next, a second embodiment will be described. FIG. 2 is a diagram showing the overall configuration of the CATV system. 1 differs from FIG. 1 only in the internal configuration of the data signal returning device. As in the first embodiment, the channel arrangement on the transmission path E is configured as shown in FIG.
The center device A is configured as shown in FIG. The control data transmitted from the center device A is configured as shown in FIG.

The data signal returning devices B1 to Bn are configured as shown in FIG. Input terminal 29 for transmission line E
And an output terminal 30. The input terminal 29 and the output terminal 30 are connected to power separation filters 70 and 71. The high-frequency signal from the transmission path E is split by the splitter 31, passes through the splitter 32, and is input to the data demodulator 25. The data demodulator 25 is a device (demodulation means) for demodulating a data signal output from the center device A to a predetermined downlink channel. The data demodulated by the data demodulator 25 is sent to the CPU 21 via the input / output interface 24.
Is read by

The CPU 21 stores a ROM 22 storing a control program for returning test data sent on a predetermined downlink channel to a predetermined uplink channel, and a unique address assigned to the data signal returning device. In which the self address storage area 231 is formed
23 are connected.

The CP via the input / output interface 24
The inspection data of the data read by U21 is output from the input / output interface 24 to the data modulator 28. The carrier corresponding to the predetermined uplink channel is output from the carrier generator 34 to the data modulator 28, whereby the data modulator 28 remodulates the test data to the predetermined uplink channel and outputs. The test data re-modulated to a predetermined upstream channel is amplified by the amplifier 27 and transmitted to the input terminal 29 side via the output switch 72 (analog switch), the splitter 32 and the splitter 31. The data modulator 28 remodulates the test data into a predetermined uplink channel and outputs the data to the transmission path E through the input terminal 29, thereby implementing data transmission means.

Next, the operation of this system will be described with reference to the flowchart of FIG. 14 showing the operation procedure of the CPU 21 of the data signal returning device. Since the configuration of the center device A is the same as that of the first embodiment, the flowchart showing the operation procedure of the CPU 41 is the same as FIG.

In the data signal return devices B 1 to Bn, control data transmitted on the downstream channel of the transmission path E is demodulated by the data demodulator 25. Then, steps 300 to 304 of FIG.
Do the same as.

If the address data of the control data matches the self address, the output switch 72 is turned on in step 306, and the output of the amplifier 27 is connected to the transmission line E. Further, at step 308, the test data demodulated to the data modulator 28 is output from the input / output interface 24. Then, the carrier is input to the data modulator 28, where the carrier generated by the carrier generator 34 is re-modulated to a predetermined uplink channel with the test data, and is input to the amplifier 27. The remodulated test data is amplified by the amplifier 27, and the output switch 72, the duplexer 32,
The data is transmitted to the transmission line E through the branching device 31 (data transmission means). As a result, the inspection data sent from the center device to the transmission path E is returned to the center device A from the specified data signal return device via the predetermined uplink channel.

By demodulating the test data once and then re-modulating it as in the above embodiment, it is possible to prevent the deterioration of the signal of the test data on the downlink transmission line. In other words, the original data can be completely restored unless the signal is degraded so that the data bit is inverted when the data is demodulated, so that the influence of the degradation of the test data signal on the downlink transmission path can be eliminated.

Next, a third embodiment will be described. The entire configuration is configured as shown in FIG. The configuration is the same as that of FIG. 2 except for the internal configurations of the center device and the data signal returning device. The center device is configured as shown in FIG. The function of the address setting unit 46 is the same as in the second embodiment. The data setting unit 48 designates inspection data to be returned from the data signal returning device (return data specifying means). The various data set are output to the data modulator 45 by the function of the CPU 41 as in the second embodiment. An inspection data storage area 432 in which inspection data and an identification code for identifying the inspection data are stored in the RAM 43.
Are added to the RAM 43 of the second embodiment.

The control data transmitted from the center device A is configured as shown in FIG. That is, the test data is constituted by a test data identification code instead of the test data of FIG. Second
The control data is output from the input / output terminal 51 to the downstream channel of the transmission line E in the same manner as in the embodiment. Further, the return data demodulated in the same manner as in the second embodiment and the test data stored in the test data storage area 432 (data storage means) designated by the data setting device 48 are used for the second test.
Data communication quality is output from the communication quality output device 50 in the same manner as in the embodiment.

The data signal returning devices B1 to Bn are configured as shown in FIG. The difference from the second embodiment is that R
The program stored in the OM 22 is a control program for extracting test data corresponding to the test data identification code sent on the downlink channel and returning the data to a predetermined uplink channel. Test data storage area 2 in which the identification code is stored
32 (data storage means) is added.

The test data is extracted from the test data storage area 232 by the test data identification code out of the data read by the CPU 21, and the high frequency carrier is modulated by the test data in the data modulator 28 in the same manner as in the second embodiment. Then, the signal is transmitted from the input terminal 29 to the designated uplink channel of the transmission path E.

Next, the operation of the present system will be described with reference to FIG. 18 which shows the operation procedure of the CPU 41 of the center device A, and FIG. 19 which shows the operation procedure of the CPU 21 of the data signal returning device. The operator operates the address setting device 46 in the center device A as in the second embodiment. Further, the operator operates the data setting device 48 to specify the inspection data requested to be returned (return data specifying means).

Step 400 corresponds to step 100 in FIG.
Is the same as That is, the position specifying means is implemented. In step 402, the data setting unit 48 specifies the inspection data requested to be returned (return data specifying means). In step 404, the identification code of the read test data is extracted from the data signal storage area 432. Next, in step 406, control data in a format as shown in FIG. 16 is created and transmitted to the downstream channel of the transmission line E (data transmission means) as in the second embodiment.

By performing this operation, the test data corresponding to the test data identification code transmitted to the predetermined downlink channel is returned from the addressed data signal return device on the predetermined uplink channel. Steps 408 to 412 are the same as steps 106 to 110 in FIG. 10, and the communication quality monitoring means is executed.

In the data signal returning devices B1 to Bn, steps 500 to 506 are the same as steps 300 to 306 in FIG. In the above step, demodulation means and address determination means are implemented. Step 508
In step (1), test data corresponding to the test data identification code is extracted from the data storage area 232, and the extracted data is output to the data modulator 28 via the input / output interface 24 in step 510. With this operation, the data modulator 28 modulates a high-frequency carrier having a predetermined frequency with a predetermined method using test data corresponding to the test data identification code transmitted from the center apparatus A, and transmits the modulated data as in the second embodiment. The signal is sent to the upstream channel of the path E. As a result, the inspection data specified to be returned from the center device is returned from the specified data return device to the center device A using a predetermined uplink channel (data transmission means).

In the above embodiment, the inspection data to be transmitted from the data signal returning device can be specified from the center device by setting a plurality of types of inspection data. However, this inspection data may be one type. In this case, the inspection data identification code for specifying the type of the inspection data becomes unnecessary. Further, in the above-described embodiment, the inspection data to be transmitted from the data signal returning device can be specified from the center device. However, the inspection data is specified by the data signal returning device, and the inspection data May be sent. In this case, the center device extracts test data corresponding to the test data identification code sent from the data signal return device from the test data storage area 432, and measures data communication quality based on the extracted data and the return data.

In all of the above embodiments, it is assumed that the uplink channel for returning the test data is predetermined, but as described in claims 8, 9 and 10,
The uplink channel to be returned from the center device to the data signal returning device each time may be designated. In the first embodiment, an embodiment in which an uplink channel to be returned is specified is referred to as a fourth embodiment.
Will be described as an example.

The overall configuration is as shown in FIG. The configuration is the same as that of FIG. 1 except for the internal configurations of the center device and the data signal returning device. The center device is configured as shown in FIG. A channel setting unit 47 for specifying a channel whose data communication quality is to be monitored is added to FIG. 7 of the center device of the first embodiment.

The control data transmitted from the center device A is configured as shown in FIG. That is, the channel identification data is added to the control data of the first embodiment shown in FIG. As in the first embodiment, the control data is transmitted to the input / output terminal 5.
1 is output to the downstream channel of the transmission path E. In addition, the communication quality output device 50 outputs the data communication quality using the returned inspection data and the inspection data set by the data setting unit 48 as in the first embodiment.

The data signal returning devices B1 to Bn are configured as shown in FIG. The difference from the first embodiment is that R
That is, the channel frequency storage area 233 is added to the AM 23 and the frequency to be converted is instructed to the frequency converter 26 from the input / output interface 24. That is, the channel frequency storage area 233 is used by the channel identification data among the data read by the CPU 21.
The frequency to which the inspection data is to be converted is extracted from the data, and is instructed to the frequency converter 26. The test data input to the frequency converter 26 is frequency-converted to the channel specified by the channel identification data, passes through the amplifier 27, the analog switch 72, the duplexer 32, and the splitter 31, and is input from the input terminal 29 side. The data is transmitted on the designated uplink channel of the transmission path E.

Next, the operation of this system will be described with reference to the flowchart of FIG.
The operation procedure of the CPU 21 of the data signal returning device will be described with reference to the flowchart in FIG. The operator operates the address setting device 46 and the data setting device 48 in the center device A as in the first embodiment. Further, the user operates the channel setting unit 47 to specify a channel for returning the inspection data.

Step 600 corresponds to step 100 in FIG.
These are the same steps. That is, the position specifying means is implemented. In step 602, channel identification data unique to the channel set by the channel setting unit 47 is read (channel specifying means). Step 604 corresponds to FIG.
This is the same step as step 102.

Next, at step 606, control data in the format as shown in FIG. 21 is created and transmitted to a predetermined downlink channel of the transmission line E as in the first embodiment (data transmission means). Based on the control data created in step 606, the test data sent to the predetermined downlink channel is returned from the addressed data signal return device on the uplink channel specified by the channel setting device. Steps 608 to 612 are the same as steps 106 to 110 in FIG. 10, and the communication quality monitoring means is executed.

In the data signal returning devices B1 to Bn, steps 700 to 706 are the same as steps 200 to 206 in FIG. In the above step, demodulation means and address determination means are implemented. Next, in step 708, channel frequency data corresponding to the channel identification data is extracted from the channel frequency storage area 233, and in step 710, the input / output interface 2
4 outputs the channel frequency data to the frequency converter 26. As a result, the test data input to the frequency converter 26 is frequency-converted into an uplink channel corresponding to the channel identification data and transmitted to the transmission path E (data transmission means).

In the above embodiment, the fourth embodiment has been described as the embodiment in which the uplink channel to be returned is specified in the first embodiment. However, in the second and third embodiments, the upstream channel to be returned is specified. An embodiment in which a channel is specified can be similarly considered.

Next, a description will be given of a fifth embodiment in which the test data in the test data storage area of the third embodiment is initialized by the center. The entire configuration is configured as shown in FIG. The configuration is the same as that of FIG. 1 except for the internal configurations of the center device and the data signal returning device. Figure 2 shows the center device
It is configured as shown in FIG. The data setting unit 48 can set new inspection data in addition to the functions of the third embodiment. The CPU 41 has the same function as the third embodiment when the existing test data is designated by the data setting device 48. When the test data is newly written by the data setting device 48, the test data newly set by the data setting device 48 and the test data identification code corresponding to the data are written into the data signal storage area 432, and the test data, The data identification code and the write command generated in the CPU 41 are transmitted to the data modulator 45 through the output interface 44.
Output function. The ROM 42 stores a test data writing program 423 (initial setting means) in addition to the third embodiment.

When the existing inspection data is designated as the control data sent from the center device A, the control data is configured as shown in FIG. 16 as in the third embodiment. When new inspection data is designated, it is configured as shown in FIG. That is, the control data is address data, command data for giving an operation command such as a write command to the data signal returning device,
It consists of a test data identification code and test data.

The data signal returning devices B1 to Bn are configured as shown in FIG. The difference from the third embodiment is that R
A data transmission program 221 for extracting test data corresponding to the test data identification code sent to the OM 22 on the downlink channel and returning the check data to the designated uplink channel; This means that a data writing program 222 (initial setting means) for writing data is stored. The data transmission program 221 is the same as the contents stored in the ROM 22 of the third embodiment.

If the control data sent from the center device A is configured as shown in FIG.
1 executes the same program as in the third embodiment. When the control data transmitted from the center device A is configured as shown in FIG. 26, the inspection data and the inspection data identification code read by the CPU 21 are stored in the inspection data storage area 232.
Is written to.

Next, the operation of this system will be described with reference to the flowchart of FIG.
The operation procedure of the CPU 21 of the data signal returning device will be described with reference to a flowchart in FIG. The operator operates the address setting device 46 in the center device A as in the third embodiment. Further, the user operates the data setting unit 48 to specify existing inspection data or set new inspection data.

In step 800, the data set in the data setting unit 48 is read. Next, step 80
In step 2, the contents read in step 800 are determined. If the data stored in the test data storage area 432 is designated, step 804 is executed, and if new test data is set, step 816 is executed.

Step 804 corresponds to step 400 in FIG.
Steps 806 to 814 correspond to step 40 in FIG.
Steps similar to steps 4 to 412 are performed. That is, the third
Extraction of inspection data, transmission of control data, and measurement and output of data communication quality, which were performed in the embodiment, are performed.

At step 816, an inspection data identification code is assigned to the new inspection data read at step 800. Next, in step 818, a data write command is generated. Next, in step 820, the test data and its identification code are written to the test data storage area 432. Next, in step 822, control data in the format shown in FIG. 26 is created and output to the data modulator 45 via the output interface 44. The data modulator 45 modulates the high-frequency carrier with the control data and sends the modulated carrier to the downstream channel of the transmission line E. In steps 816 to 822, the initial setting means in the center device A is executed.

In the data signal returning devices B 1 to Bn, the control data transmitted on the downstream channel of the transmission path E is demodulated by the data demodulator 25. Then, in step 900, this control data is read via the input / output interface 24. Next, step 902
In, the format of the read control data is determined,
In the case of the format of FIG. 16, step 902 is executed, and in the case of the format of FIG. 26, step 914 is executed.

Steps 904 to 912 are similar to steps 502 to 510 in FIG. That is,
Inspection data specified to be returned from the center device is returned from the specified data signal returning device to the center device A using a predetermined uplink channel. In step 914, the test data and its identification code are stored in the test data storage area 2
33 (initial setting means). In the above-described embodiment, a plurality of types of test data are used, and a plurality of types of test data to be sent out from the center device for writing to the data signal returning device are used as an initial setting. However, one type of test data may be used. In this case, the inspection data identification code for specifying the type of the inspection data becomes unnecessary.

Further, in all of the above embodiments, the communication quality is measured by comparing the received test data with the original test data transmitted and measuring the rate of data corruption. Thus, the waveform distortion and the phase distortion may be directly measured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of the present invention for a first embodiment.

FIG. 2 is a block diagram showing the overall configuration of the present invention for a second embodiment.

FIG. 3 is a block diagram showing the overall configuration of the present invention for a third embodiment.

FIG. 4 is a block diagram showing the overall configuration of the present invention for a fourth embodiment.

FIG. 5 is a block diagram showing the overall configuration of the present invention for a fifth embodiment.

FIG. 6 is an explanatory diagram showing a channel arrangement on a transmission path.

FIG. 7 is a block diagram illustrating a configuration of a center device according to the first embodiment.

FIG. 8 is an explanatory diagram showing the configuration of control data for the first embodiment.

FIG. 9 is a block diagram showing a configuration of a data return device according to the first embodiment.

FIG. 10 is a flowchart illustrating a CPU processing procedure of the center device according to the first embodiment;

FIG. 11 shows the CP of the data return device according to the first embodiment.
9 is a flowchart illustrating a U processing procedure.

FIG. 12 is an explanatory diagram showing a configuration of other control data according to the first embodiment.

FIG. 13 is a block diagram showing a configuration of a data return device according to a second embodiment.

FIG. 14 shows the CP of the data return device according to the second embodiment.
9 is a flowchart illustrating a U processing procedure.

FIG. 15 is a block diagram illustrating a configuration of a center device according to a third embodiment.

FIG. 16 is an explanatory diagram showing a configuration of control data for the third embodiment.

FIG. 17 is a block diagram showing a configuration of a data return device according to a third embodiment.

FIG. 18 is a flowchart illustrating a CPU processing procedure of the center device according to the third embodiment.

FIG. 19 is a diagram showing a CP of the data return device according to the third embodiment;
9 is a flowchart illustrating a U processing procedure.

FIG. 20 is a block diagram showing a configuration of a center device according to a fourth embodiment.

FIG. 21 is an explanatory diagram showing a configuration of control data for a fourth embodiment.

FIG. 22 is a block diagram showing a configuration of a data return device according to a fourth embodiment.

FIG. 23 is a flowchart illustrating a CPU processing procedure of the center device according to the fourth embodiment.

FIG. 24 is a diagram showing a CP of a data return device according to a fourth embodiment;
9 is a flowchart illustrating a U processing procedure.

FIG. 25 is a block diagram showing a configuration of a center device according to a fifth embodiment.

FIG. 26 is an explanatory diagram showing the configuration of control data for the fifth embodiment.

FIG. 27 is a block diagram showing a configuration of a data return device according to a fifth embodiment.

FIG. 28 is a flowchart illustrating a CPU processing procedure of the center device according to the fifth embodiment;

FIG. 29 shows the CP of the data return device according to the fifth embodiment.
9 is a flowchart illustrating a U processing procedure.

[Explanation of symbols]

 A: center device B1 to Bn: data signal return device C: head end D1 to Dn: relay amplifier E: transmission line F1: customer terminal X1: data generation means X2: channel designation means X3: position designation means X4: data transmission Means X5 ... Communication quality monitoring means X6 ... Data storage means X7 ... Return data designation means X8 ... Initial setting means Y1 ... Demodulation means Y2 ... Address determination means Y3 ... Modulation means Y4 ... Data transmission means Y5 ... Data storage means Y6 ... Initial setting Means 26 frequency converter 28 data modulator 46 address setting device 47 channel setting device 48 data setting device

Claims (14)

[Claims] 1. A system for monitoring, at a center, the data communication quality of an upstream band transmission line between a center of a two-way CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line, the system being installed at the center. A center device and a data signal returning device disposed at the arbitrary position are provided, wherein the center device designates inspection data for monitoring data communication quality and the data signal returning device requesting the return of the inspection data. An address data transmitting unit that receives the inspection data returned via a predetermined uplink channel and monitors the data communication quality. When specified by the device, the test data transmitted and received from the center device is transmitted to the predetermined uplink channel. A data communication quality monitoring system in a CATV system, wherein 2. A center apparatus used in a system for monitoring data communication quality of an upstream band transmission line between a center of a bidirectional CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line at the center, Data generating means for generating inspection data for monitoring data communication quality; position specifying means for specifying an arbitrary return position of the inspection data on a transmission line; specifying the inspection data and a position specified by the position specifying means Data transmission means for transmitting address data to be transmitted to a predetermined downlink channel; and communication quality monitoring for receiving inspection data returned from the designated position via the predetermined uplink channel of the transmission path and monitoring data communication quality. And a means. 3. An arbitrary transmission line used in a system for monitoring a data communication quality of an upstream band transmission line between a center of a bidirectional CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line at the center. In a data signal returning device disposed at a position, demodulation means for receiving a signal from a predetermined downlink channel and demodulating address data; and determining whether or not the address data demodulated by the demodulation means is data designating its own device. Address determination means for determining whether or not the own device is specified by the address determination means, frequency-converts the test data transmitted on the downstream channel of the transmission line, and the predetermined uplink channel A data signal returning device comprising: a data transmission unit that transmits the data signal to a transmission path. 4. A transmission line used in a system for monitoring data communication quality of an upstream band transmission line between a center of a bidirectional CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line at the center. In a data signal returning device disposed at a position, a signal is received from a predetermined downlink channel, demodulating means for demodulating address data and test data, and the address data demodulated by the demodulating means designates its own device. Address determining means for determining whether the data is data, modulating means for re-modulating the test data demodulated by the demodulating means, and modulating by the modulating means when the address determining means specifies its own device. Data transmission means for transmitting the test data to the transmission path on a predetermined uplink channel. Data signal return unit. 5. A system for monitoring data communication quality of an upstream band transmission line between a center of a two-way CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line, the system being installed at the center. A center device and a data signal returning device disposed at the arbitrary position are provided, wherein the center device sends address data designating the data signal returning device requesting return of inspection data;
A device for receiving inspection data returned via a predetermined uplink channel and monitoring data communication quality, wherein the data signal returning device is configured such that when its own device is designated by the center device by the address data, Is a device for returning stored inspection data for monitoring data communication quality on the predetermined uplink channel, wherein the data communication quality is monitored in a CATV system. 6. A center device used in a system for monitoring data communication quality of an upstream band transmission line between a center of a two-way CATV system having an upstream channel and a downstream channel and an arbitrary position of the transmission line, the center device comprising: Data storage means for storing test data for monitoring data communication quality; position designating means for designating an arbitrary return position of test data on a transmission line; and return designating test data to request transmission on a predetermined uplink channel Data specifying means, data transmitting means for transmitting address data specifying the position specified by the position specifying means to a predetermined downlink channel, and data transmission means transmitting from the specified position via the predetermined uplink channel of the transmission line. Communication quality monitoring means for receiving the inspection data and monitoring data communication quality. The other apparatus. 7. An arbitrary transmission line used in a system for monitoring data communication quality of an uplink band transmission line between a center of a bidirectional CATV system having an uplink channel and a downlink channel and an arbitrary position of the transmission line at the center. In a data signal returning device disposed at a position, data storage means for storing inspection data for monitoring data communication quality; demodulation means for receiving a signal from a predetermined downlink channel and demodulating address data; Address determining means for determining whether or not the address data demodulated by the self-device is data specifying the own device; and, when the self-device is specified by the address determining means, the check stored in the data storage means. Data transmission means for transmitting data to the transmission path via a predetermined uplink channel. Return devices. 8. The center device also transmits channel identification data designating an uplink channel to which the test data is returned, receives the test data returned via the designated uplink channel, and monitors data communication quality. The CATV system according to claim 1 or 5, wherein the data signal returning device is a device that returns the inspection data on the designated uplink channel designated by the channel identification data. Data communication quality monitoring system. 9. The center device has channel designation means for designating an arbitrary uplink channel to be monitored, and the data transmission means also has a predetermined channel identification data unique to the channel designated by the channel designation means. Communication means for transmitting data on a downlink channel, wherein the communication quality monitoring means receives inspection data returned from the designated position via the designated uplink channel of the transmission path and monitors data communication quality; 7. The center device according to claim 2, wherein the center device is a quality monitoring unit. 10. The demodulating means is also a demodulating means for demodulating channel identification data, and the data transmitting means is a means for transmitting the check data on an uplink channel corresponding to the channel identification data demodulated by the demodulating means. 8. The data signal returning device according to claim 3, wherein the data signal sending device is a data sending unit that sends the data signal to a transmission path. 11. The center apparatus according to claim 2, wherein the data transmitting means transmits the test data and the other data through separate downlink channels. 12. The data communication quality monitoring system in a CATV system according to claim 5, wherein said inspection data is transmitted from said center device and written in said data signal returning device. 13. An address data, the test data, and a write command data are transmitted to a predetermined downlink channel for initial setting of test data for monitoring data communication quality. 7. The center apparatus according to claim 6, wherein an initial setting unit for writing the inspection data is provided in a data signal returning device for transmitting data. 14. The data signal returning device according to claim 7, further comprising an initial setting means for storing the inspection data sent from the center device in the data storage means as the initial setting.