JPH05268118A - Terminal equipment and line characteristic correction control method therefor - Google Patents

Abstract

PURPOSE:To provide the terminal equipment with high communication quality inexpensively with respect to the terminal equipment used while being connected to a private communication line and the line characteristic correction control method. CONSTITUTION:A control section 28a receiving a test signal SS whose frequency is a predetermined frequency and whose signal level is a prescribed level sent from a terminal equipment 24 at other terminal, in a terminal equipment provided with an oscillator section 25a connecting to a transmission line, outputting the test signal SS and able to control variably an oscillating frequency, a characteristic correction section 26a connecting to a reception line and able to control variably a line frequency characteristic correction quantity, a level detection section 27a detecting an output signal level of the characteristic correction section 26a, a control section 28a implementing the variable control of an oscillation frequency of the oscillation section 25a and the variable control of a line gain correction quantity of the characteristic correction section 26a upon the receipt of the result of detection of the level detection section 27a, controls the line frequency characteristic correction of the characteristic correction section 26a so that the reception signal level detected by the level detection section 27a is a predetermined level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal device for communication which is used by connecting to a dedicated communication line provided by a telecommunications carrier, and a method for controlling the line characteristic correction of the dedicated communication line by the terminal device.

When a terminal device such as a communication device or a data communication device is connected to a dedicated line for use, it is necessary to correct the characteristics of the dedicated line in order to ensure communication quality.

This characteristic correction is performed by the ATT provided in the terminal device.
(Attenuater) or a frequency equalizer, etc., but in the past, a professional engineer manually adjusted and set the ATT or frequency equalizer using a measuring device. That is, it was a costly operation.

Therefore, there is a demand for a terminal device that can easily (automatically) correct the line characteristics and a correction control method therefor.

[0005]

2. Description of the Related Art FIG. 7 is a block diagram for explaining a conventional method for correcting the characteristics of a leased line.

That is, the two terminal devices 9 and 10 are connected to both ends of the dedicated line 8 so that the terminal devices 9 and 10 can communicate with each other.

(1) Configuration for Line Characteristic Correction in Terminal Device Each terminal device 1 (2) is provided with an ATT unit 3 (5) and a frequency equalizer unit 4 (6) in a cascade connection state, and transmits. The signal S _TX is directly sent to the leased line 11, but the received signal S _RX is obtained after the line characteristics are corrected by the ATT unit 3 (5) and the frequency equalizer unit 4 (6). ..

The ATT section 3 (5) is a means for correcting the gain characteristic, and the frequency equalizer section 4 (6) is a means for correcting the frequency characteristic. The ATT unit 3 (5) and the frequency equalizer unit 4 (6) are configured to manually adjust and set the correction amount. As another configuration example, A
There is also a terminal device provided with an amplifier for compensating for the shortage of the line gain before the TT unit 3 (5).

(2) Line characteristic correction work In order to perform the line characteristic correction work in the configuration of (1), the oscillator 7 (9) for outputting and transmitting a reference test signal is transmitted.
And a level meter 8 (1
0) and 0 are required for each terminal 1 (2) side. Further, an operator who performs the correction work is also required on each terminal device 1 (2) side.

When the correction work is performed, the oscillator 7 (9) is connected to the dedicated line 11 to send a test signal to the other terminal device side, and the level meter 10 (8) is used for the ATT unit 5 (3). The output signal level of is measured to correct the gain characteristic, and the output signal level of the frequency equalizer unit 6 (4) is measured to correct the frequency characteristic.

For example, the oscillation frequency of the oscillator 7 on one side of the terminal device 1 is set to 1 kHz and its output level is set to 0 dbm, and the level signal 10 on the side of the other terminal device 2 measures the output signal level of the ATT section 5. , The value of the ATT section 5 is set so that the signal level becomes 0 dbm.

Next, the oscillation frequency of the oscillator 7 on the terminal device 1 side is set to 3 KHz and its output level is set to 0 dbm, and the level signal 10 on the terminal device 2 side measures the output signal level of the frequency equalizer section 6 and The equalizing characteristic of the frequency equalizer unit 6 is set so that the signal level becomes 0 dbm.

That is, the line characteristic correction work in the terminal device 2 is completed as described above. The same applies to the line characteristic correction work in the terminal device 1. That is, the test signal (1 kHz, 0 dbm and 3
KHz, 0dbm) is transmitted, and the ATT unit 3 and the frequency equalizer unit 4 are adjusted and set.

[0014]

However, such characteristic correction work requires a professional engineer who is familiar with the measuring device, the terminal device, and the leased line. Also, in the characteristic correction work, there is a possibility that an artificial error, that is, a human error may occur.

Therefore, not only the working cost becomes high,
Should there be an error in the line characteristic correction work, the communication quality between the terminal devices concerned will be degraded.

A technical problem of the present invention is to realize a terminal device capable of automatically correcting the characteristics of a leased line, and to establish a correction control method in the terminal device to thereby improve communication quality and reliability. To provide a highly reliable terminal device at low cost.

[0017]

FIG. 1 is a block diagram for explaining the structure of the present invention. In addition, FIG. 2 is a communication procedure diagram illustrating how to perform the characteristic correction control.
In FIG. 2, time progresses downward in the figure.

The present invention is characterized in that the terminal devices 12 (13) are configured to be able to mutually perform line characteristic correction work while performing handshake communication.

(1) Configuration of Communication Terminal Device-1 That is, the terminal device has the following constituent requirements.

An oscillator 14a which is connected to the transmission line and outputs a test signal S _S for measuring the line characteristic, and which is capable of variably controlling at least the oscillation frequency.

A characteristic correction unit 15a connected to the reception path and capable of variably controlling at least the line frequency characteristic correction amount.

A level detector 16a for detecting the output signal level of the characteristic corrector 15a.

A control unit 17a for inputting the detection result of the level detection unit 16a and performing variable control of the oscillation frequency of the oscillation unit 14a and variable control of the line gain correction amount of the characteristic correction unit 15a.

(2) Configuration of Communication Terminal Device-2 That is, a terminal device having the following constituent requirements.

An oscillator 14a which is connected to a transmission line and outputs a test signal S _S for measuring the line characteristics and which is capable of variably controlling at least the oscillation frequency.

A characteristic correction unit 15a connected to the reception path and capable of variably controlling at least the line frequency characteristic correction amount and the line gain correction amount.

Level detector 16a for detecting the output signal level of the characteristic corrector 15a

The detection result of the level detecting unit 16a is input, and the oscillating frequency of the oscillating unit 14a is variably controlled, and the line frequency characteristic correcting amount and the line gain correcting amount of the characteristic correcting unit 15a are variably controlled. Control unit 17a

(3) Line Characteristic Correction Control Method in Configuration-1 of Communication Terminal Device In this characteristic correction control method, one terminal device 12 and the other terminal device 13 are provided with the above-mentioned configuration (1). The condition is to use the device.

That is, the control unit 17a, which has received the test signal S _S having a predetermined frequency and a predetermined signal level, which is transmitted from the terminal device 13 at the other end, controls the level detection unit 16a.
This is a method of controlling the line frequency characteristic correction amount of the characteristic correction unit 15a so that the magnitude of the received signal level detected by a becomes a predetermined magnitude, and setting the correction amount.

A characteristic correction control method in the terminal device 13
The same applies to the test signal S _SWho sends
It just moves from the terminal device 13 to the terminal device 12.

(4) Line Characteristic Correction Control Method in Configuration-2 of Communication Terminal Device Also in this characteristic correction control method, one terminal device 12 and the other terminal device 13 are provided with the configuration of the above (2). The condition is that a terminal device is used.

That is, the control unit 17a, which has received the test signal S _S having a predetermined frequency and a predetermined signal level, which is transmitted from the terminal device 13 at the other end, controls the level detection unit 16a.
This is a method of controlling the line frequency characteristic correction amount and the line gain correction amount of the characteristic correction unit 15a so that the magnitude of the received signal level detected by a becomes a predetermined predetermined magnitude, and setting the correction amount.

A characteristic correction control method in the terminal device 13
The same applies to the test signal S _SWho sends
It just moves from the terminal device 13 to the terminal device 12.

[0035]

(1) Operation in the configuration-1 of the communication terminal device In the terminal device having this configuration, the test signal S _S can be transmitted and given to the terminal device at the other end. Further, the line frequency characteristic can be corrected so that the received test signal S _S reaches a predetermined signal level determined in advance. Note that these operations can be automatically performed by the control unit 17a.

By the way, if a microcomputer system is used for the control unit 17a, the correction control can be realized by the software.

(2) Operation in the configuration-2 of the communication terminal device In the configuration-2 of the communication terminal device, a configuration capable of gain correction is added to the characteristic correction unit of the configuration-1.

Therefore, it is possible to automatically correct the line frequency characteristic and the line gain characteristic.

(3) Operation of the line characteristic correction control method in the configuration-1 By using the terminal device of the present invention as the terminal device 12 on one side and the terminal device 13 on the other side, the terminal devices 12 and 13 handshake each other. It is possible to control and set the line frequency characteristic correction amount of the terminal devices 12 and 13 while performing communication.

That is, by transmitting the test signal S _S from the terminal device 12 to the terminal device 13, the line frequency characteristic in the terminal device 13 can be corrected, and the test signal from the terminal device 13 to the terminal device 12 can be corrected. If S _S is sent, the terminal device
It is possible to correct the line frequency characteristic in 12.

(4) Operation of the line characteristic correction control method in the configuration-2 This line characteristic correction control method can automatically perform the line gain correction in addition to the line frequency characteristic correction of the above (3). it can.

That is, it is possible to control and set the line frequency characteristic correction amount and the line gain characteristic correction amount of the terminal devices 12 and 13 while performing the handshake communication.

[0043]

EXAMPLES Next, examples of how the terminal device according to the present invention and the line characteristic correction control method in the terminal device can be realized in practice will be described.

(1) Configuration FIG. 3 is a diagram for explaining the configuration of the embodiment, and is a block diagram showing the configuration of the terminal device.

The terminal device shown in FIG. 3 has a modem section 24 for modulating and demodulating data, and the signal processing section 22 communicates with a data processing section 29 not shown in the figure, while using the dedicated line 28 as a communication medium. It is a mechanism for controlling data communication. It is to be noted that the voice communication by the transmission voice signal S _TA and the reception voice signal S _RA is also possible.

That is, the modem section 24, to which the transmission data is given from the signal processing section 22, outputs a signal subjected to MSK modulation or FSK modulation, and the adding section 30 and the transmission buffer section 25, 2 lines / 4.
The configuration is such that modulated data is transmitted to a dedicated line through the line conversion unit 27.

On the other hand, the received modulated data is input to the modem section 24 through the 2-line / 4-line converting section 27, the receiving buffer section 26 and the ATT section 19, and the demodulated data is passed through the signal processing section 22 to the data processing section 29. It is a structure to give to.

Although the transmission voice signal S _TA is directly applied to the adding unit 30, the reception voice signal S _RA is supplied to the ATT unit 19.
The frequency equalizer unit 20 connected to the subsequent stage corrects the frequency characteristic and then outputs the corrected frequency characteristic.

By the way, the A / D (Analog to Digital) conversion section 21 connected to the subsequent stage of the frequency equalizer section 31 is means for A / D converting the received signal level and giving it to the signal processing section. The oscillation frequency and the output signal level are controlled by the signal processing unit 22, and a test signal for correcting the characteristics of the leased line 28 is output and transmitted through the adding unit 30.

The attenuation amount of the ATT unit 19 and the equalizing amount of the frequency equalizer unit 20 are controlled by the signal processing unit 22, and the switch unit 23 is an interface means for giving a command to the signal processing unit 22.

In other words, the signal processing unit 22 controls the communication of data communication and controls the oscillation unit 18, the ATT unit 19 and the frequency equalizer unit 20 to control the line characteristic correction of the dedicated communication line 28. is there. Incidentally, the signal processing unit 22 is composed of a microcomputer system.

(2) Line Characteristic Correction Control Procedure The characteristic correcting operation of the leased line 28 can be realized by the software of the signal processing unit 22 in the terminal device having the configuration of this embodiment.

FIG. 4, FIG. 5, and FIG. 6 are diagrams for explaining a series of line characteristic correction control procedures. Communication between the terminal devices that connect the correction control procedures to both ends (end A and end B) of the leased line. It is the figure which it explained together with the procedure. The communication procedure referred to here means the communication and the procedure required for performing the line characteristic correction work. The communication subject is the signal processing unit 22.

Next, the correction control procedure will be described by dividing it into two stages of 1) a rough adjustment stage and 2) a main adjustment stage. The procedure is as indicated by the symbol a. ~ D. Follow along. Further, the equalizing amount of the frequency equalizer unit is 0 before adjustment.
(Zero).

1) Coarse adjustment stage a. Correction Start Operation (End A) The operator operates the switch unit of the terminal device at the end A, which is one terminal unit, to give a correction start command. Then, the signal processing unit waits until data is received while varying the attenuation amount of the ATT unit.

A. Correction start operation (end B) b. Similarly, the operator operates the switch unit of the terminal device at the B end to give a correction start command. Then, the signal processing unit waits until data is received while varying the attenuation amount of the ATT unit.

The a. After operating the switch section of, a. If there is no mistake in the order in which the switch section is operated, even a person who does not have technical knowledge can perform the operation. Alternatively, one operator can operate the terminal device at the A end and then move to the B end to operate the terminal device.

C. Coarse adjustment start operation, test command-1
(B end → A end) Then, the switch unit of the terminal device at the B end is operated to give a rough adjustment start command. Then, the terminal device at the B terminal transmits the test command-1 for adjusting the terminal device at the A terminal.

That is, the operation of the switch unit for starting the characteristic correction control is performed three times in total. The test command-1 is command data promised in advance (hereinafter, test command-1 to test command-6 are provided, but all are command data promised in advance). Output and send.

D. Reception range measurement (End A) Obtain the maximum attenuation ATT _MAX and minimum ATT _MIN of the ATT unit that can receive the test command-1. If the attenuation amount of the ATT unit is too large, the received signal becomes too small to be demodulated by the modem unit, and if the attenuation amount is too small, the received signal is saturated and distorted, and similarly demodulated by the modem unit. I can't.

E. Rough adjustment of ATT section (A end) Set the value of the ATT section to the intermediate value ATT _TYP given by the following equation (1).

ATT _TYP = (ATT _MAX -ATT _MIN ) / 2 ---------- (1)

F. Coarse adjustment end notification (End A → End B) ACK (Acknowl) indicating that the temporary setting of the ATT section is completed
Send test command-1 to edge B as the (edge character).

G. Measurement of reception range (End B) d. Similarly, the maximum attenuation ATT _MAX and minimum ATT of the ATT unit that can receive the test command-1
_{Find MIN} .

C. Coarse adjustment of ATT part (B end) Set the value of the ATT part to the intermediate value ATT _TYP given by the following equation (2). The formula (2) is the same formula as the formula (1).

ATT _TYP = (ATT _MAX -ATT _MIN ) / 2 ---------- (2)

K. Notification of coarse adjustment end (B end → A end) As an ACK indicating that the temporary setting of the ATT unit is completed,
Send test command-2 to terminal A.

2) Main adjustment stage Start adjustment, send tone signal for adjustment (B end → A
End) The tone signal of 1.2 KHz, 0 dbm is transmitted from the oscillating unit for a certain period of time, and then the test command-3 which means that the tone signal is transmitted is transmitted from the modem unit. By the way, this composite signal is cyclically transmitted at fixed time intervals.

Service. Adjustment of ATT part (A end) The received 1.2KHz tone signal level becomes the optimum value A
Set the amount of attenuation in the TT section.

Shi. Notification of the adjustment end of the ATT section (A end → B
End) The test command-2 is transmitted to the B end as an ACK indicating that the setting of the ATT section is completed.

S. Transmission of adjustment tone signal (End A → B
End) The tone signal of 1.2 KHz, 0 dbm is transmitted from the oscillating unit for a certain period of time, and then the test command-3 which means that the tone signal is transmitted is transmitted from the modem unit. By the way, this composite signal is cyclically transmitted at fixed time intervals.

C. Adjustment of ATT part (End B) The received 1.2KHz tone signal level becomes the optimum value A
Set the amount of attenuation in the TT section.

So. Notification of adjustment completion of ATT part (B end → A
End) Send test command-4 to the A terminal as an ACK indicating that the setting of the ATT section is completed.

T. Adjustment command start of frequency equalizer section, transmission of adjustment tone signal (end B → end A) Test command meaning that tone signal of 3kHz, 0dbm was sent from oscillator for a certain period of time and then the tone signal was sent- Send 5 from the modem section. By the way, this composite signal is cyclically transmitted at fixed time intervals.

H. Adjustment of the frequency equalizer section (A terminal) Set the equalizing amount of the frequency equalizer section where the received 3KHz tone signal level becomes the optimum value.

Tsu. Notification of the end of adjustment of the frequency equalizer section (End A → End B) ACK indicating that the setting of the frequency equalizer section has been completed
As a result, the test command-4 is transmitted to the B end.

Te. Transmission of adjustment tone signal (End A → B
End) A tone signal of 3 KHz, 0 dbm is transmitted from the oscillating unit for a certain period of time, and then a test command-5, which means that the tone signal is transmitted, is transmitted from the modem unit. By the way, this composite signal is cyclically transmitted at fixed time intervals.

G. Adjustment of the frequency equalizer section (End B) Set the equalizing amount of the frequency equalizer section where the received 3KHz tone signal level becomes the optimum value.

Na. Transmission of correction end notification (B end → A end) A test command-6 is transmitted to the A end as an ACK indicating that the setting of the frequency equalizer unit and all correction work have been completed.

D. Completion of correction work (End A) Upon reception of the test command-6, it is recognized that all correction work has been completed, and the program shifts to a program for performing normal data communication processing.

[0081]

As described above, according to the terminal device and the line characteristic correction control method of the present invention, even a person who does not have specialized technology can automatically perform the dedicated line characteristic correcting operation. .. In addition, no artificial correction error occurs.

Further, since the characteristic correction work is performed while the terminal devices connected to both ends of the dedicated line communicate with each other, one worker can perform all the work.

Therefore, it is possible to inexpensively provide a terminal device having high communication quality and high reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the principle of the present invention.

FIG. 2 is a diagram for explaining the principle of the present invention, and is a communication procedure diagram for explaining how to perform characteristic correction control.

FIG. 3 is a diagram illustrating a configuration of an embodiment, and is a block diagram illustrating a configuration of a terminal device.

FIG. 4 is a diagram for explaining the operation of the embodiment and is a diagram showing a series of line characteristic correction control procedures. Note that FIG. 4 continues to FIG.

FIG. 5 is a diagram for explaining the operation of the embodiment and is a diagram showing a series of line characteristic correction control procedures. Note that FIG. 5 is a continuation of FIG. 4 and continues to FIG.

FIG. 6 is a diagram for explaining the operation of the embodiment and is a diagram showing a series of line characteristic correction control procedures. Note that FIG. 6 is a continuation of FIG.

FIG. 7 is a block diagram illustrating a conventional method for correcting characteristics of a dedicated line.

[Explanation of symbols]

1,2 Terminal equipment 3,5 ATT (Attenuater) section 4,6 Frequency equalizer section 7,9 Oscillator 8,10 Level meter 11,28 Dedicated line 12,13 Terminal equipment 14a, 14b Oscillation section 15a, 15b Characteristic correction section 16a , 16b Level detection section 17a, 17b Control section 18 Oscillation section 19 ATT section (electronic volume) 20 Frequency equalizer section 21 A / D (Analog to Digital) conversion section 22 Signal processing section 23 Switch section 24 Modem section 25,26 Buffer section 27 2-wire / 4-wire converter 29 Data processor 30 Adder S _TX Transmit signal S _RX Receive signal S _TA Transmit signal (transmit voice signal) S _RA Receive signal (receive voice signal) S _S test signal ENQ _-S line ENQ (Enquiry Character) ACK _-S which means to start correction control of characteristics ACK (Acknowledge Character) ACK _-E which means that preparation for correction control of line characteristics is completed ACK to

Claims (4)

[Claims] 1. A terminal device (2) connected to a dedicated communication line (8).
3), which is connected to the transmission path and is a test signal (S _S ) for measuring line characteristics
And an oscillation unit (25a) capable of variably controlling the oscillation frequency, and a characteristic correction unit (26a) connected to the reception path and capable of variably controlling at least the line frequency characteristic correction amount, A level detection unit (27a) for detecting the output signal level of the characteristic correction unit (26a), and a detection result of the level detection unit (27a) are input,
A terminal unit comprising: a control unit (28a) that performs variable control of the oscillation frequency of the oscillation unit (25a) and variable control of the line gain correction amount of the characteristic correction unit (26a). 2. A terminal device (2) connected to a dedicated communication line (8).
3), which is connected to the transmission path and is a test signal (S _S ) for measuring line characteristics
Which is capable of variably controlling the oscillation frequency, and a characteristic correction unit which is connected to the receiving path and which can variably control at least the line frequency characteristic correction amount and the line gain correction amount. (2
6a), a level detection unit (27a) for detecting the output signal level of the characteristic correction unit (26a), and a detection result of the level detection unit (27a) are input,
A control unit (28a) that performs variable control of the oscillation frequency of the oscillation unit (25a) and variable control of the line frequency characteristic correction amount and line gain correction amount of the characteristic correction unit (26a). Characteristic terminal device. 3. A terminal device (2) connected to a dedicated communication line (8).
3), which is connected to the transmission path and is a test signal (S _S ) for measuring line characteristics
And an oscillation unit (25a) capable of variably controlling the oscillation frequency, and a characteristic correction unit (26a) connected to the reception path and capable of variably controlling at least the line frequency characteristic correction amount, A level detection unit (27a) for detecting the output signal level of the characteristic correction unit (26a), and a detection result of the level detection unit (27a) are input,
A terminal unit comprising: a control unit (28a) for variably controlling the oscillation frequency of the oscillating unit (25a) and variably controlling the line gain correction amount of the characteristic correcting unit (26a). The control unit (28a), which has received the test signal (S _S ) of a predetermined frequency and a predetermined signal level transmitted from the device (24), receives the signal level detected by the level detection unit (27a). The line characteristic correction control method is characterized in that the line frequency characteristic correction amount of the characteristic correction unit (26a) is controlled so that the size of the line becomes a predetermined size. 4. A terminal device (2) connected to a dedicated communication line (8).
3), which is connected to the transmission path and is a test signal (S _S ) for measuring line characteristics
Which is capable of variably controlling the oscillation frequency, and a characteristic correction unit which is connected to the receiving path and which can variably control at least the line frequency characteristic correction amount and the line gain correction amount. (2
6a), a level detection unit (27a) for detecting the output signal level of the characteristic correction unit (26a), and a detection result of the level detection unit (27a) are input,
A terminal unit comprising: a control unit (28a) for variably controlling the oscillation frequency of the oscillating unit (25a) and variably controlling the line gain correction amount of the characteristic correcting unit (26a). The control unit (28a), which has received the test signal (S _S ) of a predetermined frequency and a predetermined signal level transmitted from the device (24), receives the signal level detected by the level detection unit (27a). The line characteristic correction control method is characterized in that the line frequency characteristic correction amount and the line gain correction amount of the characteristic correction unit (26a) are controlled so that the size of the line becomes a predetermined size.