JP7170616B2 - Communication data recorder - Google Patents

Description

The present application relates to a communication data recording device.

ITU-T Recommendation V.2000 is used for wide-area monitoring and control systems used in plant facilities. Communication is carried out using modems operating in the voice frequency band according to V.32. This V.I. Since signals between modems conforming to H.32 are analog voice signals, the frequency characteristics are likely to deteriorate due to the effects of external noise, communication line quality, and the like. When the frequency characteristics of the analog voice signal deteriorate, a communication error occurs such as the modem being unable to receive the analog voice signal. As a method of investigating the cause of such a communication error, there is a method of recording an audio signal when the communication error occurs and analyzing the recorded content to identify the cause of the communication error.

As a communication device for recording communication data when a communication error occurs, there has been disclosed a communication device for detecting a bit error when receiving digital data, although it is not an analog signal, and recording the received data in which the bit error has occurred. (See Patent Document 1, for example).

WO2014/097420

In a conventional communication device, received data is recorded in a cyclic recording type memory, and when a bit error in received data is detected, received data before receiving processing, demodulated data after receiving processing, and received data are received. A table is created that associates the timing with the bit number of the demodulated data.

However, although the received data with the bit error is recorded in the table created when the bit error occurs, the received data before and after the error is not recorded. Therefore, it is conceivable to read the received data before and after the occurrence of the error later from among the received data recorded in the cyclic recording type memory. However, since the received data is recorded in the cyclic recording type memory, if the communication device continues to operate after the error occurs, the received data at the time of the error may be overwritten. In such a situation, there is a problem that the received data before and after the occurrence of the error cannot be read from the cyclic recording type memory even if the cause of the error occurrence is to be analyzed later.

SUMMARY OF THE INVENTION The object of the present invention is to provide a communication data storage device capable of reliably storing communication data before and after a communication failure occurs. do.

A communication data recording apparatus according to the present application includes an AD conversion unit that converts a transmission/reception analog audio signal transmitted/received by a modem into a transmission/reception digital audio signal, a ring buffer that temporarily stores the transmission/reception digital audio signal converted by the AD conversion unit, and a modem. A point setting unit that receives the signal quality indication signal and the carrier detection signal output by and sets the recording start point and the recording end point based on the received signal quality indication signal and carrier detection signal, a memory control unit for reading the transmission/reception digital audio signal in a period from the recording start point set by the point setting unit to the recording end point from the transmission/reception digital audio signal, and recording the read transmission/reception digital audio signal in a memory; .

The communication data recording apparatus of the present application comprises a point setting unit for setting a recording start point and a recording end point based on a signal quality display signal and a carrier detection signal output from a modem, and a transmission/reception digital audio signal temporarily stored in a ring buffer. and a memory control unit that reads out the transmission/reception digital audio signal in the period from the recording start point set by the point setting unit to the recording end point, and records the read transmission/reception digital audio signal in the memory. It is possible to reliably store communication data before and after the occurrence of a communication abnormality when it occurs.

1 is a configuration diagram of a communication data recording device according to Embodiment 1; FIG. FIG. 4 is an explanatory diagram of a recording start point and a recording end point in Embodiment 1; 2 is a configuration diagram of a communication data recording device according to Embodiment 2; FIG. FIG. 11 is a configuration diagram of a communication data recording device according to Embodiment 3;

Hereinafter, a communication data recording device according to an embodiment for carrying out the present application will be described in detail with reference to the drawings. In each figure, the same reference numerals denote the same or corresponding parts.

Embodiment 1.
FIG. 1 is a configuration diagram of a communication data recording apparatus according to Embodiment 1. As shown in FIG. ITU-T Recommendation V. A modem 1 conforming to V.32 transmits a modulated analog voice signal to an analog IF circuit 2 and demodulates the analog voice signal sent from the analog IF circuit 2 . Here, ITU-T Recommendation V.2. The modem 1 conforming to V.32 is a modem that performs communication at a maximum communication speed of 9,600 bps. The analog IF circuit 2 is an interface circuit that serves as a relay for exchanging data between devices using analog signals. Since the modem 1 is a modem that communicates by a two-wire connection, the signals transmitted and received between the modem 1 and the analog IF circuit 2 are the transmission analog voice signal from the modem 1 and the reception analog signal from the analog IF circuit 2. It is a transmission/reception analog audio signal on which an audio signal is superimposed. The transmission/reception analog voice signal is input to the communication data recording device 3 of the present embodiment.

The communication data recording device 3 includes an AD conversion section 31 , a ring buffer 32 , a point setting section 33 , a memory control section 34 and a memory 35 . The AD converter 31 has a function of converting an analog signal into a digital signal. A transmission/reception analog voice signal transmitted/received between the modem 1 and the analog IF circuit 2 is input to the AD conversion section 31 . The AD converter 31 converts the input transmission/reception analog audio signal into a transmission/reception digital audio signal and sends the transmission/reception digital audio signal to the ring buffer 32 .

The ring buffer 32 temporarily stores the received and transmitted digital audio signals. The ring buffer 32 is a recording device of a cyclic recording type, in which the head and tail of a certain area of memory are connected, and input data can be cyclically recorded.

The point setting unit 33 monitors a signal quality detection signal (hereinafter referred to as an SQD signal) and a carrier detection signal (hereinafter referred to as a CD signal) output by the modem 1, When an abnormality in the SQD signal and CD signal is detected, a recording start point and a recording end point are set based on the received SQD signal and CD signal. Here, the SQD signal is a signal determined by the bit error rate of the digital audio signal demodulated from the analog audio signal by the modem 1. When the bit error rate exceeds 1×10 ⁻³ , the SQD signal is turned off. It is a signal that turns on when it is 1×10 ⁻³ or less. The CD signal is a signal indicating a carrier detection state, and is turned off when the carrier strength detected by the modem 1 is below a certain threshold, and is turned on when it exceeds the threshold. A carrier means a digital voice signal demodulated from an analog voice signal in modem 1 . Therefore, when the analog voice signal transmitted and received by the modem 1 is normal, both the SQD signal and the CD signal are on. When the analog voice signal transmitted and received by the modem 1 deteriorates, the bit error rate first increases and then the carrier strength decreases, so the SQD signal is turned off first, and then the CD signal is turned off. In other words, abnormalities in the SQD signal and the CD signal mean that both the SQD signal and the CD signal are turned off from on.

FIG. 2 is an explanatory diagram showing the recording start point and the recording end point set by the point setting section 33 in this embodiment. When the address of the data temporarily stored in the ring buffer 32 corresponding to the time when the SQD signal is turned off is n, the point setting unit 33 records n−S of the address S before that address. Set as starting point. Further, if the address of the data temporarily stored in the ring buffer 32 corresponding to the time when the CD signal is turned off is m, the point setting unit 33 records the address m+T which is T after that address. Set to end point. Here, n, m, S and T are integers of 1 or more.

As shown in FIG. 2, the memory control unit 34 reads the data in the period from n−S to m+T from the transmission/reception digital audio signal temporarily stored in the ring buffer 32, and stores the read data in the memory 35. Record. In this embodiment, the ring buffer 32, the point setting unit 33 and the memory control unit 34 are implemented in an integrated circuit called FPGA (Field Programmable Gate Array) (hereinafter referred to as FPGA). By implementing the ring buffer 32, the point setting unit 33, and the memory control unit 34 in the FPGA 36, values for setting the addresses related to the recording start point and the recording end point set by the point setting unit 33, specifically It is possible to change the values of S and T. Further, data communication among the ring buffer 32, the point setting unit 33 and the memory control unit 34, and data storage and reading in the ring buffer 32 can be performed at high speed.

In the communication data recording apparatus configured in this manner, the SQD signal and the CD signal are used as triggers to reliably store the transmitted and received digital audio signals corresponding to the transmitted and received analog audio signals before and after the occurrence of the communication abnormality when the communication abnormality occurs. can do. In addition, since the transmission/reception digital audio signals for only the required period are recorded in the memory from the transmission/reception digital audio signals temporarily stored in the ring buffer, the capacity of the memory to be used can be reduced. Furthermore, even when trying to analyze the cause of the communication abnormality later, the transmitted and received digital audio signals before and after the occurrence of the communication abnormality can be reliably read from the memory.

The ring buffer 32 is configured so that data can be recorded while the data is being read. That is, the transmission/reception digital audio signal sent from the AD converter 31 is continuously stored in the ring buffer 32 even while the memory controller 34 is reading data from the ring buffer 32 due to a communication error. . Therefore, even if a communication error occurs several times in a row, the transmission/reception digital audio signals for all communication errors are temporarily stored in the ring buffer 32 . As a result, the memory control unit 34 can read out all transmission and reception digital audio signals before and after the occurrence of the communication abnormality from the ring buffer 32 and record them in the memory 35 even if the communication abnormality occurs several times in succession.

If the SQD signal turns on before the CD signal turns off after the SQD signal turns from on to off, or if the CD signal turns off while the SQD signal is on, , the point setting unit 33 does not set the recording start point and the recording end point.

Further, the communication data recording apparatus of the present embodiment includes a memory for recording data read from the ring buffer, but this memory does not necessarily have to be provided inside the communication data recording apparatus. no. The memory that records the data read from the ring buffer may be an external memory connected to the outside of the communication data recording device, or a memory such as a USB memory that is detachable from the communication data recording device. When an external memory or removable memory is used, the cause analysis of the communication abnormality can be performed by another device independent of the communication data recording device.

Embodiment 2.
Since the modem 1 of the communication data recording apparatus of the first embodiment is a modem that performs communication by a two-wire connection, the signals transmitted and received between the modem 1 and the analog IF circuit 2 are a transmission analog audio signal and a reception analog audio signal. It is a transmission/reception analog audio signal on which an audio signal is superimposed. Among them, the main factor affecting the SQD signal and the CD signal is often the received analog voice signal received by the modem 1 from the analog IF circuit 2 . A communication data recording apparatus according to the second embodiment is obtained by adding a transmission signal removing unit to the same communication data recording apparatus as that according to the first embodiment.

FIG. 3 is a configuration diagram of a communication data recording apparatus according to this embodiment. In the communication data recording apparatus 3 of the present embodiment, as shown in FIG. 3, the input transmission/reception analog audio signal is branched into two, and one signal is input to the AD converter 31 as the transmission/reception analog audio signal. , the other signal is input to the AD converter 31 via the transmission signal remover 37 . The transmission signal removing unit 37 has a function of removing the transmission analog audio signal from the transmission and reception analog audio signal and outputting only the reception analog audio signal.

The AD conversion unit 31 converts the input transmission/reception analog audio signal and reception analog audio signal into a transmission/reception digital audio signal and a reception digital audio signal, respectively, and sends them to the ring buffer 32 . The ring buffer 32 temporarily stores the input transmission/reception digital audio signal and the received digital audio signal.
The point setting unit 33 sets a recording start point and a recording end point based on the received SQD signal and CD signal, as in the first embodiment.

The memory control unit 34 reads the data of the period from the address of the recording start point to the address of the recording end point from the transmission/reception digital audio signal and the reception digital audio signal temporarily stored in the ring buffer 32, and stores the read data in the memory. Record at 35.

In the communication data recording apparatus configured as described above, the SQD signal and the CD signal are used as triggers to reliably store the transmission and reception digital audio signals and the received digital audio signals before and after the occurrence of the communication abnormality when the communication abnormality occurs. can be done. In addition, when analyzing the causes of communication anomalies, it is also possible to refer to only the received digital audio signals corresponding to the received analog audio signals, which are the main factors affecting the SQD and CD signals, making it easier to analyze the causes of communication anomalies. Become.

Embodiment 3.
A modem may transmit and receive digital data to and from Data Terminal Equipment (DTE). A DTE is a device connected to a terminal of a communication line, and is a device for presenting received data to a user and transmitting information input by the user as data. Examples of DTE include personal computers, input/output devices such as printers and scanners. The communication data recording apparatus of the third embodiment is similar to the communication data recording apparatus of the first embodiment, and temporarily stores data terminal transmission/reception signals transmitted/received between a modem and a DTE in a ring buffer.

FIG. 4 is a configuration diagram of a communication data recording apparatus according to this embodiment. In the communication data recording device 3 of the present embodiment, as shown in FIG. 4, in the communication data recording device similar to that of the first embodiment, data terminal transmission/reception signals transmitted/received between the modem 1 and the DTE 4 are ringed. entered into the buffer. The ring buffer 32 temporarily stores the input transmission/reception digital voice signal and the data terminal transmission/reception signal.
The point setting unit 33 sets a recording start point and a recording end point based on the received SQD signal and CD signal, as in the first embodiment.

The memory control unit 34 reads the data of the period from the address of the recording start point to the address of the recording end point from the transmission/reception digital audio signal and the data terminal transmission/reception signal temporarily stored in the ring buffer 32, and stores the read data in the memory. Record at 35.

In the communication data recording apparatus constructed in this manner, the SQD signal and the CD signal are used as triggers to reliably store the transmission/reception digital audio signals and the data terminal transmission/reception signals before and after the occurrence of the communication abnormality when the communication abnormality occurs. can be done. In addition, when analyzing the cause of a communication error, it is possible to refer to the data terminal transmission/reception signal transmitted/received between the modem 1 and the DTE 4. Causality can also be analyzed.

In addition, in this embodiment, it is also possible to add the transmission signal canceller explained in the second embodiment. By adding a transmit signal remover, the received digital audio signal can also be recorded in memory. As a result, when analyzing the cause of communication anomalies, it is possible to refer to the received digital audio signals corresponding to the received analog audio signals, which are the main factors affecting the SQD and CD signals, making it easier to analyze the causes of communication anomalies. become.

Although this application describes various exemplary embodiments, the various features, aspects, and functions described in one or more embodiments may be limited to the application of particular embodiments. can be applied to the embodiments alone or in various combinations.
Therefore, countless modifications not illustrated are envisioned within the scope of the technology disclosed in the present application. For example, modification, addition or omission of at least one component, extraction of at least one component, and combination with components of other embodiments shall be included.

1 modem, 2 analog IF circuit, 3 communication data recording device, 4 DTE, 31 AD conversion unit, 32 ring buffer, 33 point setting unit, 34 memory control unit, 35 memory, 36 FPGA, 37 transmission signal removal unit.

Claims (4)

an AD converter that converts a transmission/reception analog audio signal transmitted/received by the modem into a transmission/reception digital audio signal;
a ring buffer for temporarily storing the transmitted/received digital audio signal converted by the AD converter;
a point setting unit that receives a signal quality indication signal and a carrier detection signal output from the modem and sets a recording start point and a recording end point based on the received signal quality indication signal and the carrier detection signal;
reading the transmission/reception digital audio signal of the period from the recording start point set by the point setting unit to the recording end point from the transmission/reception digital audio signal temporarily stored in the ring buffer, and reading the transmission/reception digital audio; A communication data recording device, comprising: a memory control section for recording a signal in a memory. further comprising a transmission signal removing unit for removing the transmission analog audio signal from the transmission and reception analog audio signal and outputting the reception analog audio signal;
The AD conversion unit further converts the reception analog audio signal output from the transmission signal removal unit into a reception digital audio signal,
the ring buffer further temporarily stores the received digital audio signal converted by the AD converter;
The memory control unit further reads the received digital audio signal during the period from the recording start point set by the point setting unit to the recording end point from the received digital audio signal temporarily stored in the ring buffer. 2. The communication data recording apparatus according to claim 1, wherein said received digital voice signal read out is recorded in said memory. the ring buffer further temporarily stores a data terminal transmission/reception signal transmitted/received between the modem and the data terminal equipment;
The memory control unit further reads the data terminal transmission/reception signal for a period from the recording start point set by the point setting unit to the recording end point from the data terminal transmission/reception signals temporarily stored in the ring buffer. 3. A communication data recording apparatus according to claim 1, wherein said data terminal transmission/reception signal read out is recorded in said memory. 4. The point setting unit according to any one of claims 1 to 3, wherein the point setting unit sets the recording start point and the recording end point when both the signal quality indication signal and the carrier detection signal are turned off. The communication data recording device according to the item.

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