JP2012044293A - Analog line terminal, analog signal reception method and analog signal reception program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an analog line terminal capable of correctly receiving signals from a corresponding party even when a line echo extending as much as hundreds of milliseconds occurs.SOLUTION: Each signal level of plural input signals received via an analog line 20 connected to a communication network is compared with a signal level of a received signal received just before or with a history of signal levels of input signals received from a corresponding party terminal in the past by a level detection unit 13. If the former exceeds a threshold x-dB predetermined for a signal level of an input signal received just before or a second threshold y-dB predetermined for a history of signal levels of input signals received from the partner terminal in the past, the analog line terminal 1 abandons the input signal regarding the input signal as a line echo of a transmission signal transmitted by the analog line terminal 1, and causes a signal transmission reception unit 12 to perform reception processing on the signal whose signal level is within the threshold x-dB or the second threshold y-dB as proper input signals from the partner terminal.

Description

  The present invention relates to an analog line terminal, an analog signal receiving method, and an analog signal receiving program.

  When data is transmitted / received in an analog line terminal, as shown in FIG. 3, a hybrid echo b by a data request signal a transmitted by itself is received prior to data n and data (n + 1) received from the partner terminal side. . FIG. 3 is an explanatory diagram schematically showing how data is transmitted and received in an analog line terminal. FIG. 3A shows data n and data (n + 1) from the partner terminal side in response to transmission of the data request signal a. 3B shows an ideal data reception state, and FIG. 3B shows a hybrid echo based on the data request signal a transmitted by itself before the data n and data (n + 1) received from the partner terminal side. b indicates the actual data reception state in which the data is received.

  That is, in a conventional DTMF (Dial Tone Multiple Frequency) signal applied for an analog line of an analog line terminal, a hybrid echo b delayed by about several tens of ms with respect to the data request signal a is received. However, as such hybrid echo countermeasures, for example, countermeasures such as detection guard and echo cancellation, which are described in Japanese Patent Application Laid-Open No. 9-312595, “Hands-Free Telephone”, are disclosed. .

  However, recently, in an analog line terminal in which an IP (Internet Protocol) network is constructed and an optical conversion unit or the like is connected, an unexpected delay (several hundred ms) and a line echo of a level are generated along with a transmission signal. There are more and more cases to do. For this reason, conventional hybrid echo countermeasures such as detection guard and echo cancellation cannot be used, and there are many cases where malfunctions are caused.

Japanese Patent Laid-Open No. 9-312595 (page 3-4)

  As described above, in a recent analog line terminal, a line echo with an unexpected delay time of several hundred ms occurs with respect to a transmission signal, and a hybrid by conventional detection guard and echo cancellation, etc. In many cases, the countermeasures against echo cannot cope and malfunctions are caused.

(Object of the present invention)
The present invention has been made in view of such circumstances, and the object of the present invention is to normally receive a signal from the other party even when a line echo of several hundred ms occurs. The present invention provides an analog line terminal, an analog signal receiving method, and an analog signal receiving program.

  In order to solve the above-described problems, the analog line terminal, the analog signal receiving method, and the analog signal receiving program according to the present invention mainly adopt the following characteristic configuration.

  (1) An analog line terminal according to the present invention is an analog line terminal connected to an analog line with a communication network, and each of a plurality of received signals received via the analog line after receiving an incoming call from a counterpart terminal Compared with the signal level of the received signal received immediately before, the received signal that was not within the predetermined threshold range with respect to the signal level of the received signal received immediately before is discarded, A reception process is performed using a reception signal within the threshold range as a reception signal from the counterpart terminal.

  (2) Another analog line terminal according to the present invention stores, for each partner terminal, a history of signal levels of received signals received in the past from the partner terminal in the analog line terminal connected to the analog line with the communication network. The signal level of each of the plurality of received signals received via the analog line after receiving the incoming call from the counterpart terminal is compared with the signal level history of the received signal received in the past from the counterpart terminal. The received signal that did not fall within the second threshold range determined in advance with respect to the signal level history of the received signal received from the counterpart terminal in the past is discarded and falls within the second threshold range. A reception process is performed using the received signal as received from the counterpart terminal.

  (3) An analog signal receiving method according to the present invention is an analog signal receiving method for receiving an analog signal via an analog line in an analog line terminal connected to an analog line between a communication network, Compared with the signal level of the reception signal received immediately before the signal level of each of the plurality of reception signals received via the analog line after receiving the incoming call, the signal level of the reception signal received immediately before The received signal that does not fall within the predetermined threshold range is discarded, and reception processing that uses the received signal that falls within the threshold range as the received signal from the counterpart terminal is performed.

  (4) Another analog signal receiving method according to the present invention is an analog signal receiving method for receiving an analog signal via an analog line in an analog line terminal connected to an analog line between a communication network and the counterpart terminal The signal level history of the received signal received in the past from each partner terminal is saved for each partner terminal, and the signal level of each of the plurality of received signals received via the analog line after receiving an incoming call from the partner terminal Compared with the signal level history of the received signal received in the past from the counterpart terminal, within a range of the second threshold predetermined for the signal level history of the received signal received from the counterpart terminal in the past The received signal that has not been received is discarded, and the received signal that falls within the range of the second threshold is used as a received signal from the counterpart terminal. The features.

  (5) An analog signal receiving program according to the present invention is characterized in that at least the analog signal receiving method described in (3) or (4) is implemented as a program executable by a computer.

  According to the analog line terminal, analog signal receiving method, and analog signal receiving program of the present invention, the following effects can be obtained.

  The first effect is that, as an analog line terminal, not only an analog line in which a hybrid echo that causes a delay of about several tens of ms with respect to a transmission signal is generated, but also an unexpected delay time (several hundred ms) and a level line echo. Even if it is connected to various adapters (TA (Terminal Adapter) adapters, optical conversion units, etc.) that are easy to generate, the hybrid echo and the line echo due to the transmission signal transmitted by the analog line terminal itself must be surely discarded. Therefore, it is possible to correctly receive a received signal from the counterpart terminal and to secure a good communication state.

  The second effect is that even if the signal level of the received signal from the counterpart terminal is small, the received signal from the counterpart terminal is erroneously used as a hybrid echo or a line echo by a transmission signal transmitted by the analog line terminal itself. Since it can be received reliably without being discarded, a good communication state can be ensured.

It is a block block diagram which shows an example of the block configuration of the analog line terminal which concerns on this invention. 3 is a flowchart for explaining an example of the operation of the analog line terminal shown in FIG. 1. It is explanatory drawing which shows typically a mode that data are transmitted / received in an analog line terminal.

  Preferred embodiments of an analog line terminal, an analog signal receiving method, and an analog signal receiving program according to the present invention will be described below with reference to the accompanying drawings. In the following description, the analog line terminal and the analog signal receiving method according to the present invention will be described. However, the analog signal receiving method may be implemented as an analog signal receiving program executable by a computer, or Needless to say, the analog signal receiving program may be recorded on a computer-readable recording medium.

(Features of the present invention)
Prior to the description of the embodiments of the present invention, an outline of the features of the present invention will be described first. The present invention relates to a line echo based on a signal transmitted by the counterpart terminal or a transmission signal transmitted by the analog line terminal itself depending on whether the signal level of the received signal from the analog line is a small signal level equal to or less than a predetermined threshold. This makes it possible to realize good communication even when an unexpected line echo occurs that causes a delay time of about several hundred ms with respect to the transmission signal transmitted by itself. An analog line terminal is realized.

(Configuration example of embodiment)
Next, a specific configuration example of the analog line terminal according to the present invention will be described with reference to FIG. FIG. 1 is a block configuration diagram showing an example of a block configuration of an analog line terminal according to the present invention, in which functional blocks directly related to the present invention are extracted and shown.

  The analog line terminal 1 shown in FIG. 1 includes at least a line monitoring unit 10, a line capturing circuit 11, a signal transmission / reception unit 12, a level detection unit 13, and a control unit 14.

  The line monitoring unit 10 is a part that monitors the state of the analog line 20 that is connected to the communication network, a polarity detection circuit that detects the polarity of the analog line 20, and a DC loop detection that detects the DC loop current of the analog line 20. At least a call signal detection circuit for detecting a call signal via an analog line 20 from a circuit and a communication network is provided. The line capture circuit 11 is a part that captures the analog line 20 in response to an instruction from the control unit 14 when an incoming call is received from the partner terminal, and the signal transmission / reception unit 12 receives the signal from the control unit 14. This is a part that generates a transmission signal and transmits it on the analog line 20 or receives a reception signal from the analog line 20 in response to an instruction.

  The level detector 13 is a part for detecting the signal level of the received signal from the analog line 20, and holds the peak level of the received signal as means for comparing with the signal level of the received signal received immediately before. It includes a peak hold circuit and the like. The control unit 14 is a part for controlling the entire analog line terminal 1.

(Description of operation of embodiment)
Next, an example of the operation of the analog line terminal 1 shown in FIG. 1 will be described in detail with reference to the flowchart of FIG. FIG. 2 is a flowchart for explaining an example of the operation of the analog line terminal 1 shown in FIG.

  In the flowchart of FIG. 2, first, when an incoming call is received from the counterpart terminal to the analog line terminal 1, the analog line terminal 1 detects the incoming call (call signal) in the call signal detection circuit of the line monitoring unit 10 and performs control. The control unit 14 that has notified the unit 14 (step S1) and has received the notification of the incoming call from the partner terminal controls the line capture circuit 11 to capture the analog line 20 (step S2). Thereafter, the control unit 14 controls the signal transmission / reception unit 12 to transmit a data request signal to the incoming terminal via the analog line 20 (step S3).

  After transmitting the data request signal, every time a signal is received from the analog line 20, the line monitoring unit 10 takes over the received signal to the signal receiving unit and the level detecting unit 13 of the signal transmission receiving unit 12 ( Step S4). When the level detection unit 13 receives a signal of the nth digit (n = 1, 2, 3...) From the analog line 20, the signal of the (n−1) th digit signal received immediately before that. Compare with the level (step S5).

  When the signal level of the n-th digit signal is greater than the signal level of the (n-1) -th digit signal by a predetermined threshold value x dB or more (in the case of “x dB greater than n-1 digit” in step S5) ), It is determined that the (n−1) -th digit signal received immediately before is a hybrid echo or a line echo by a transmission signal transmitted by the analog line terminal 1 itself, and the (n− 1) Discard the digit signal (step S6).

  Conversely, when the signal level of the n-th digit signal is smaller than the signal level of the (n-1) -th digit signal by a predetermined threshold value x dB (“x dB from n-1 digit” in step S5). In the case of "small"), the n-th digit signal received this time is determined to be a hybrid echo or a line echo by a transmission signal transmitted by the analog line terminal 1 itself, and the n-th digit signal is discarded. (Step S8).

  On the other hand, when the signal level of the n-th digit signal is within the predetermined threshold value xdB as compared with the signal level of the (n−1) -th digit signal (“n−” in step S5). 1 digit and within ± x dB), it is determined that the signal is the correct signal transmitted from the partner terminal (step S7), and the signal transmission / reception unit 12 determines the partner based on the instruction from the control unit 14 Reception processing as a reception signal from the terminal is performed (step S9).

  In the above description, the signal level of the nth digit signal is compared with the signal level of the (n−1) th digit signal received immediately before, and is within the predetermined threshold value xdB. Whether the received signal is received from the other terminal, or is a hybrid echo or a line echo due to the transmission signal transmitted by the analog line terminal 1. However, the present invention is not limited to such a case.

  For example, the signal level history of the received signal received in the past from the partner terminal is stored and saved in advance for each partner terminal, and after receiving an incoming call from a certain partner terminal, the signal is transmitted via the analog line 20. Each time it is received, it is based on whether or not it is within a predetermined second threshold value ydB compared with the signal level history of the received signal from the counterpart terminal that was received in the past. Thus, it may be determined whether the received signal is a received signal from the counterpart terminal, or a hybrid echo or a line echo based on a transmission signal transmitted by the analog line terminal 1.

  That is, when the signal level is within the second threshold value ydB determined in advance compared to the signal level history of the received signal from the partner terminal that has been received in the past, the correct signal received from the partner terminal is correct. If it is determined that the received signal is not within the range of the second threshold value ydB, it is determined that the received signal is a hybrid echo or a line echo transmitted by the analog line terminal 1 and discarded. You may do it.

  The history of the signal level of the received signal from the counterpart terminal that was received in the past, which is a comparison target for comparing the signal level of the received signal, is the signal of the received signal from the past counterpart terminal. An average value (average signal level) obtained by simply arithmetically averaging the levels or weighted according to the reception environment may be used, or in the signal level history of the received signal from the past counterpart terminal A minimum value may be used.

(Explanation of effect of embodiment)
As described in detail above, in the present embodiment, the following effects can be obtained.

  As the analog line terminal 1, not only an analog line in which a hybrid echo that causes a delay of about several tens of ms with respect to a transmission signal is generated, but also various adapters that easily generate line echoes of unexpected delay time (several hundred ms) and levels. Even when connected to a terminal adapter (TA (terminal adapter), optical conversion unit, etc.), it is possible to reliably discard hybrid echo and line echo due to the transmission signal transmitted by the analog line terminal 1 itself. Thus, it is possible to correctly receive the received signal from the counterpart terminal and secure a good communication state.

  Further, even when the signal level of the received signal from the counterpart terminal is low, the received signal from the counterpart terminal is erroneously discarded as a hybrid echo or a line echo by a transmission signal transmitted by the analog line terminal 1 itself. Therefore, a good communication state can be ensured.

  The preferred embodiments of the present invention have been described above. However, it should be noted that such examples are merely illustrative of the invention and do not limit the invention in any way. Those skilled in the art will readily understand that various modifications and changes can be made according to a specific application without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Analog line terminal 10 Line monitoring part 11 Line acquisition circuit 12 Signal transmission / reception part 13 Level detection part 14 Control part 20 Analog line a Data request signal b Hybrid echo n Data n + 1 Data

Claims (7)

  In the analog line terminal connected to the analog line with the communication network, the received signal received immediately before the signal level of each of the plurality of received signals received via the analog line after receiving the incoming call from the partner terminal Compared with the signal level of the received signal, the received signal that did not fall within the predetermined threshold range with respect to the signal level of the received signal received immediately before is discarded, and the received signal falls within the threshold range. The analog line terminal is characterized in that reception processing is performed as a received signal from the counterpart terminal.   For analog line terminals connected to an analog line with a communication network, the signal level history of received signals received from the other terminal in the past is saved for each other terminal, and the incoming call from the other terminal is accepted The signal level of each of the plurality of received signals received via the analog line is compared with the signal level history of the received signal received from the counterpart terminal in the past, and the received signal received from the counterpart terminal in the past A received signal that does not fall within the predetermined second threshold range with respect to the signal level history is discarded, and a received signal that falls within the second threshold range is received from the counterpart terminal. An analog line terminal characterized by performing reception processing as:   The received signal received from the partner terminal in the past as a history of the signal level of the received signal to be compared for the signal level of each of the plurality of received signals received via the analog line after receiving the incoming call from the partner terminal The analog line terminal according to claim 2, wherein an average value or a minimum value of the signal level history is used.   An analog signal receiving method for receiving an analog signal via an analog line in an analog line terminal connected to an analog line between a communication network, and after receiving an incoming call from a partner terminal, the analog line via the analog line The signal level of each of the plurality of received signals received does not fall within a predetermined threshold range with respect to the signal level of the received signal received immediately before, compared to the signal level of the received signal received immediately before. An analog signal receiving method, wherein the received signal is discarded, and a received signal that falls within the threshold range is received as a received signal from the counterpart terminal.   An analog signal receiving method for receiving an analog signal via an analog line in an analog line terminal connected to an analog line with a communication network, wherein a history of signal levels of received signals received from a counterpart terminal in the past For each signal level of the plurality of received signals that are stored for each partner terminal and received via the analog line after receiving an incoming call from the partner terminal, the signal level of the received signal received in the past from the partner terminal Compared with the history of the received signal, the received signal that did not fall within the predetermined second threshold range with respect to the signal level history of the received signal received in the past from the counterpart terminal is discarded, and the second A method for receiving an analog signal, comprising: performing reception processing using a received signal falling within a threshold range as a received signal from the counterpart terminal.   The received signal received from the partner terminal in the past as a history of the signal level of the received signal to be compared for the signal level of each of the plurality of received signals received via the analog line after receiving the incoming call from the partner terminal 6. The analog signal receiving method according to claim 5, wherein an average value or a minimum value of the signal level history is used.   7. An analog signal reception program, wherein the analog signal reception method according to claim 4 is implemented as a program executable by a computer.

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