JP2001217933A - Return loss measurement device, and return loss measuring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently and quickly measure the return loss of an analog phone terminal. SOLUTION: In the return loss measurement device 1 that measures the return loss of a device 5 to be measured, a controller 3 controls a changeover circuit 24 to switch the connection state so as to disconnect the device 5 from the return loss measurement device 1. Calibration data denoting leaked power and the reception loss of a measurement section 2 are acquired and stored in a memory 31. Then the controller 3 controls the changeover circuit 24 to connect the device 5 to the return loss measurement device 1. Then the return loss of the device 5 is measured on the basis of the calibration data stored in the memory 31 and a measurement value of a level meter LM1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a return loss measuring device for measuring a return loss of an analog telephone terminal device,
And a return loss measuring method.

[0002]

2. Description of the Related Art An analog telephone terminal connected to a public line network must satisfy a predetermined standard determined by the Telecommunications Terminal Equipment Examination Association or the like. For this reason, various measurements are performed at the time of manufacture, and a typical example is a return loss.

[0003] FIG. 7 shows a procedure of a conventional return loss measurement. Normally, return loss is measured by connecting an analog telephone terminal device as a device under test to a return loss measuring device.

First, in step S101, a return loss measuring device is used instead of an analog telephone terminal device.
For example, a standard terminator having a resistance of 600Ω (ohm) is switched and connected.

In step S102, measurement conditions such as a measurement frequency and a loss in a pseudo line are set. In step S103, under the measurement conditions set in step S102, the leakage power of the return loss measuring device, the reception loss, and the like are measured, and calibration data necessary for calibration is obtained.

Subsequently, in step S104, the device connected to the return loss measuring device is switched from the standard terminator to the analog telephone terminal device as the device under test, and in step S105, power supply to the analog telephone terminal device starts. Is done.

In step S106, step S103
The return loss is measured based on the calibration data obtained in step (1). In step S107, it is determined whether the measurement under all the measurement conditions has been completed. Generally, the return loss of an analog telephone terminal device is measured under 20 measurement conditions. If it is determined in step S107 that the measurement has not been performed under all the conditions, the process returns to step S101, and the return loss is measured under the next measurement condition.

[0008] In addition to the return loss during the standby operation of the analog telephone terminal device, the return loss during the hold operation and other various operations are measured.

[0009]

However, in the conventional return loss measurement, there is a problem that it takes time since calibration data acquisition and return loss measurement are repeated for each measurement condition. In particular, when measuring the return loss of a plurality of analog telephone terminal devices, calibration data must be acquired every time the analog telephone terminal devices are changed, and there is a problem that it takes a long time. The calibration data is hard to change unless a power OFF / ON operation of the return loss measuring device or a change in the device configuration is performed. Therefore, there is a problem that the procedure for acquiring the calibration data every time the analog telephone terminal device is changed is very inefficient.

In the conventional return loss measurement shown in FIG. 7, the power supply to the analog telephone terminal is turned off in step S101 every time the measurement conditions are changed. When measuring the return loss during the hold operation of the analog telephone terminal device, the hold operation is reset by turning off the power supply, and it is necessary to manually set the hold operation again. In addition, the timing of setting the hold state may affect the measurement, which may hinder accurate measurement. Thus, in the conventional return loss measurement procedure,
There is a problem that it is difficult to measure an accurate return loss in each operation state of the analog telephone terminal device, which is troublesome.

An object of the present invention is to efficiently and quickly measure the return loss of an analog telephone terminal device.

[0012]

In order to solve the above-mentioned problems, the invention according to claim 1 provides a return loss measuring device (1) for an analog telephone terminal device (for example, a device under test 5 shown in FIG. 1). A calibration means for acquiring calibration data of the return loss measuring device (for example, the control device 3 performing the processing shown in FIG. 5) and a storage means for storing calibration data acquired by the calibration means (for example, FIG. 1) And a measuring means (for example, the control device 3 for performing the processing shown in FIG. 6) for measuring the return loss of the analog telephone terminal device based on the calibration data stored in the storage means. It is characterized by the following.

Here, the analog telephone terminal device refers to, for example, a telephone, a facsimile or a modem connected to a public line network via an analog interface, but may be a device having other functions. In addition, the calibration data indicates the leakage power and the reception loss of the return loss measuring device itself, and indicates various data necessary for calibration.

According to the first aspect of the present invention, in the return loss measuring device for an analog telephone terminal device, the calibration data of the return loss measuring device is acquired by the calibration device, and the calibration data acquired by the calibration device is stored in the storage device. The return loss of the analog telephone terminal device is measured by the measurement unit based on the calibration data stored in the storage unit.

According to a fifth aspect of the present invention, there is provided a method for measuring return loss of an analog telephone terminal device, wherein the step of acquiring calibration data of the return loss measuring device and storing the acquired calibration data in a storage means. And a step of measuring a return loss of the analog telephone terminal device based on the calibration data stored in the storage means.

Therefore, when measuring the return loss, the calibration data stored in the storage means may be read, and it is not necessary to repeat the acquisition of the calibration data and the measurement of the return loss as in the conventional case. Therefore, the return loss of a plurality of analog telephone terminal devices can be measured in a short time by acquiring the calibration data only once in advance. As a result, the process and time involved in return loss measurement can be significantly reduced, efficiency can be improved, and work load can be reduced.

According to a second aspect of the present invention, in the return loss measuring apparatus according to the first aspect, the calibration means acquires calibration data under a plurality of measurement conditions, and the storage means
Each calibration data acquired by the calibration means is stored in association with a measurement condition.

According to the second aspect of the invention, calibration data under a plurality of measurement conditions is acquired by the calibration means, and the calibration data acquired by the calibration means is stored in the storage means in association with the measurement conditions.

Therefore, when measuring the return loss under a plurality of measurement conditions, the calibration data corresponding to the relevant measurement conditions may be read from the storage means. Also, since the calibration data is stored in association with the measurement conditions, it can be read out quickly. As a result, the return loss under a plurality of measurement conditions can be measured in a short time, and the efficiency can be further improved.

According to a third aspect of the present invention, in the return loss measuring apparatus according to the second aspect, the calibration means continuously acquires calibration data under the plurality of measurement conditions prior to the return loss measurement by the measurement means. It is characterized by doing.

According to the third aspect of the present invention, the calibration means continuously acquires calibration data under a plurality of measurement conditions prior to the return loss measurement by the measurement means.

Therefore, since the calibration data under a plurality of measurement conditions is acquired first, the return loss measurement of the analog telephone terminal device can be performed continuously and quickly thereafter. In particular, when there are a plurality of analog telephone terminal devices to be measured and the return loss is measured under a plurality of measurement conditions, the time required for the measurement can be greatly reduced, and the measurement can be performed more efficiently and quickly. Further, after the calibration data is continuously obtained, only the return loss measurement can be continuously performed, so that the analog telephone terminal device remains powered during the measurement. Therefore, there is no need to stop or interrupt the power supply to the analog telephone terminal device, and the return loss can be measured while maintaining a stable operation state.

According to a fourth aspect of the present invention, in the return loss measuring device according to any one of the first to third aspects, the calibration data obtained by the calibration means includes a leak power and a reception loss of the return loss measuring device. The data is characterized by:

According to the fourth aspect of the present invention, the calibration data acquired by the calibration means is data indicating the leakage power of the return loss measuring device and the reception loss.

Therefore, a return loss measuring apparatus which can quickly measure the return loss excluding the influence of the leakage power and the receiving loss of the return loss measuring apparatus is provided, which is more convenient, improves the efficiency and reduces the work load. it can.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of a return loss measuring device 1 to which the present invention is applied. As shown in FIG. 1, the return loss measuring device 1 includes a measuring unit 2 and a control device 3.
The measuring unit 2 includes the hybrid circuit 21, the power supply circuit 22, the pseudo line 23, the switching circuit 24, the standard terminator 25, the level meters LM1 and LM2, the resistance R, the oscillator OSC, and the like. . The control device 3 includes a memory 31 therein. Although not shown, each unit of the measurement unit 2 is connected to the control device 3 and operates according to the control of the control device 3.

The switching circuit 24 includes a hybrid circuit 21
And a pseudo line 23, and a standard terminator 25 and an oscillator OSC. When the measurement unit 2 measures the return loss of the device under test 5, the switching circuit 2
A device under test 5 is externally connected to 4. The switching circuit 24 switches the connection state of each device according to a control signal input from the control device 3. For example, hybrid circuit 2
1 is connected by switching either the standard terminator 25 or the oscillator OSC, and the pseudo line 23 is connected by switching any of the standard terminator 25, the oscillator OSC or the device under test 5.

The hybrid circuit 21 includes a level meter LM1, a resistor R, a power supply circuit 22, and a switching circuit 24.
Is connected. The hybrid circuit 21 is a so-called two-wire / four-wire conversion circuit. The device under test 5 to be measured is an analog telephone terminal device, and the measuring unit 2 and the device under test 5 are connected by a two-wire line. Therefore, the hybrid circuit 21 and the power supply circuit 22 are connected by a two-wire line. The hybrid circuit 21 interconnects a two-wire line on the power supply circuit 22 side and a four-wire line through which a signal including a control signal is transmitted,
Perform processing for signal separation or combination.

For example, the oscillator OS
When an oscillation signal is input from C, the hybrid circuit 2
1 outputs the oscillation signal to the power supply circuit 22. Also, for example, the power supply circuit 2 via a two-wire line
2 to separate the input signal from the level meter LM1.
Output to

The power supply circuit 22 is a hybrid circuit 2
1 and the pseudo line 23, and supplies power to the line on the side of the pseudo line 23. The power supplied by the power supply circuit 22 is, for example, a DC power of 48 V DC.

The pseudo line 23 is a line connecting the power supply circuit 22 and the switching circuit 24. The pseudo line 23 changes transmission characteristics under the control of the control device 3 and simulates various line characteristics. Therefore, the return loss measuring device 1 can change the characteristics of the pseudo line 23 and measure the return loss of the device under test 5 when various lines are used.

For example, the pseudo line 23 is a line having a loss of 0 dB (decibel), a line having a line length of 0.4 mm and a loss of 3 dB, and a line length of 0.4 dB.
Five characteristics can be reproduced: a line with a loss of 7 dB in mm, a line with a loss of 3 dB at a line of 0.65 mm, and a line with a loss of 7 dB at a line of 0.65 mm.

The standard terminator 25 is a terminator having a built-in resistor having a predetermined resistance value. In this embodiment, it is assumed that the standard terminator 25 has a resistance of 600Ω (ohm) as an example.

The oscillator OSC outputs a transmission signal of a predetermined frequency under the control of the control device 3. Note that the oscillator O
The oscillation frequency of the SC is variable under the control of the control device 3, for example, 0.3 kHz (kilohertz), 1.0 kHz, 2.0 kHz.
It can be set to four types of z and 3.4kHz.

The device under test 5 is an analog telephone terminal device, and is a device to be measured by the measuring section 2 for return loss measurement.

The level meters LM1 and LM2 measure the signal level. The level meter LM1 is connected to the hybrid circuit 21, and the level meter LM2 is connected to the line connecting the power supply circuit 22 and the pseudo line 23. It is connected.

The resistor R is a resistor connected to the hybrid circuit 21 and has a resistance value of, for example, 600Ω.

The control device 3 reads out and executes the control program stored in the built-in memory 31, and controls each unit of the measuring unit 2. The control device 3 executes a calibration measurement process (FIG. 5) to be described later, causes the return loss measuring device 1 to measure the leakage power and the reception loss, and stores the leakage power data and the reception loss data in the memory 31. Further, various related data are calculated based on the leakage power data and the reception loss data, and are stored in the memory 31. In the memory 31, the leakage power data, the reception loss data, and various related data are stored in association with measurement conditions such as the characteristics of the pseudo line 23 and the oscillation frequency of the oscillator OSC.

In the present embodiment, the memory 3
1, the leakage power data, the reception loss data,
And various related data are collectively referred to as calibration data.

Further, the control device 3 executes a return loss measuring process (FIG. 6), and based on the measured value of the level meter LM1 and the calibration data in the memory 31,
Find the return loss of

The memory 31 is a flash memory, EEP
It is constituted by a nonvolatile semiconductor storage element such as a ROM and an EPROM, and stores various programs executed by the control device 3 and data relating to the various programs. Further, the memory 31 stores calibration data acquired in a calibration measurement process (FIG. 5) described later. Note that the memory 31
Aside from the nonvolatile semiconductor memory element, a RAM (Rand
om Access Memory). Then, for example, various programs and data related to the programs may be stored in a non-volatile semiconductor storage element, and the calibration data may be temporarily stored in a volatile semiconductor storage element.

Here, various measuring methods in the return loss measuring device 1 will be described. FIG. 2 is a block diagram illustrating a connection state of the measuring unit 2 when acquiring leakage power data from among the calibration data of the return loss measuring device 1.

As shown in FIG. 2, when measuring the leakage power, the connection state in the switching circuit 24 (FIG. 1) is switched, and the oscillator OSC is connected to the hybrid circuit 21.
The standard terminator 25 is connected to the pseudo line 23. Therefore, the power supply circuit 22 supplies power to the standard terminator 25.

In the return loss measuring device 1 shown in FIG. 2, when a predetermined oscillation signal is output from the oscillator OSC,
The oscillating signal is output by the hybrid circuit 21 to the power supply circuit 22 side as indicated by the symbol B in the figure.

Here, when the signal level is measured by the level meter LM1, the measured value of the level meter LM1 is
It shows the power leaking in the direction indicated by the symbol A in the figure. Therefore, the leakage power can be measured by measuring the leakage power of the return loss measuring device 1 from the measurement value of the level meter LM1, and the leakage power data can be acquired by the control device 3.

FIG. 3 is a block diagram showing the connection state of the measuring unit 2 when acquiring the reception loss data from the calibration data of the return loss measurement device 1. As shown in the figure,
At the time of reception loss data measurement, the connection state in the switching circuit 24 (FIG. 1) is switched, and the oscillator OS
C is connected, and the standard terminator 25 is connected to the hybrid circuit 21.
Is connected.

In the return loss measuring device 1 shown in FIG. 3, when a predetermined oscillation signal is output from the oscillator OSC,
The oscillation signal is output to the level meter LM1 by the hybrid circuit 21. That is, the oscillating signal output from the oscillator OSC includes a pseudo line 23, a power supply circuit 22, and a hybrid
1 to the level meter LM1.

Here, the power supply circuit 22 and the pseudo line 23
When the signal level is measured by the level meter LM2 connected between the two and the level meter LM1 connected to the hybrid circuit 21, the measured value of each level meter may show a different value.

The difference between the measured values of the level meters LM1 and LM2 indicates the reception loss when a signal is transmitted via the power supply circuit 22 and the hybrid circuit 21. Accordingly, in the state shown in FIG. 3, the signal level is measured by the level meters LM1 and LM2 under the control of the control device 3,
By calculating the difference between the measured values, the reception loss of the return loss measuring device 1 can be measured, and the reception loss data can be obtained.

FIG. 4 is a block diagram showing a connection state of the measuring unit 2 when the return loss measuring device 1 measures the return loss of the device under test 5. In the state shown in the figure, the hybrid circuit 2 is switched via the switching circuit 24 (FIG. 1).
1 is connected to the oscillator OSC, and the device under test 5 is connected to the pseudo line 23.

When measuring the return loss, the oscillator O
When a predetermined oscillation signal is output from the SC, the oscillation signal is output by the hybrid circuit 21 to the device under test 5 via the power supply circuit 22 and the pseudo line 23.

That is, the oscillation signal output from the oscillator OSC is transmitted to the device under test 5 through the hybrid circuit 21, the power supply circuit 22, and the pseudo line 23, and the pseudo line 23 and the power supply The response is returned to the hybrid circuit 21 via the circuit 22. Here, the signal measured by the level meter LM1 is attenuated via the device under test 5. Therefore, the level meter LM1
The signal level is measured by the hybrid circuit 2
1 is obtained, including the influence of the leakage power and the loss due to passing through the hybrid circuit 21 and the power supply circuit 22.

For this reason, if the control device 3 performs an arithmetic process excluding the effects of the leakage power of the return loss measuring device 1 and the reception loss, only the return loss of the device under test 5 is obtained from the measured value of the level meter LM1. Can be

Next, the operation of the return loss measuring device 1 will be described. FIG. 5 is a flowchart showing a calibration data acquisition process executed in the return loss measuring device 1.

In step S11 of the calibration data acquisition process,
The control device 3 disconnects the device under test 5 from the measuring unit 2 by controlling the switching circuit 24 to switch the connection state. By the process of step S11, the pseudo line 23 and the device under test 5 are disconnected even if the device under test 5 is set in the measurement section 2, and the device under test 5 is not supplied with power.

In step S12, the control device 3 sets the measurement conditions, and controls the oscillation frequency of the oscillator OSC and the characteristics of the pseudo line 23 according to the set conditions. The measurement conditions include the oscillation frequency of the oscillator OSC and the transmission characteristics of the pseudo line 23. As exemplified above, four frequencies can be set in the oscillator OSC,
When five types of characteristics can be set in the pseudo line 23, 20 types of conditions can be set depending on the combination. In step S12, a condition that has not been measured among the 20 conditions is set.

In step S13, the control device 3 measures the leakage power of the measuring section 2 under the conditions set in step S12 to acquire the leakage power data, and obtains various related data from the acquired leakage power data. calculate. In addition, the control device 3 measures the reception loss of the measurement unit 2 to obtain the reception loss data, and calculates various related data from the reception loss data. In step S13, the leakage power data is obtained as data in mA (milliampere), and the reception loss data is obtained as data in dB (decibel).

In step S14, the control device 3 stores the leakage power data and the reception loss data acquired in step S13 and the various data related in step S13 in the memory in association with the measurement conditions set in step S12. 31 is stored.

In step S15, the control device 3 determines whether or not measurement has been performed under all measurement conditions. And said 2
If there is a condition that has not been measured among the 0 types of measurement conditions, the process returns to step S11, and if the measurement under all the measurement conditions has been completed, the process ends.

After the above-described calibration data acquisition processing is completed, the calibration data of the return loss measuring device 1 under all measurement conditions is stored in the memory 31.

Subsequently, the control device 3 executes a return loss measuring process shown in FIG. FIG. 6 is a flowchart illustrating the return loss measurement process.

Step S21 of Return Loss Measurement Processing
Then, the control device 3 switches the connection state of the switching circuit 24 to connect the pseudo line 23 and the device under test 5. Here, the device under test 5 is supplied with power by the power supply circuit 22.

In step S22, control device 3 determines whether or not the communication state of device under test 5 has been set.
The return loss of the device under test 5 is measured for a plurality of communication states of the device under test 5 such as a non-communication state and a hold state. For this reason, in step S22, it is determined whether or not the target communication state is set in the device under test 5.

If the communication state is not set in step S22, the process waits until the communication state is set, and if the communication state is set, the process proceeds to step S23.

In step S23, the control device 3 sets measurement conditions, and controls the oscillation frequency of the oscillator OSC and the characteristics of the pseudo line 23 according to the set conditions. The measurement conditions are the 20 types of measurement conditions described in step S12 of the calibration data acquisition process in FIG. In step S23, conditions that are not measured among the above 20 conditions are set.

In step S24, the control device 3 measures the return loss of the device under test 5 under the conditions set in step S23. That is, as shown in FIG. 4, in a state where the oscillation signal is output from the oscillator OSC to the device under test 5, the signal level of the signal returned from the device under test 5 is measured by the level meter LM1. Then, the calibration data of the return loss measuring device 1 under the same measurement conditions is read out from the data stored in the memory 31, and the return of the device under test 5 is performed based on the read calibration data and the measurement value of the level meter LM1. Ask for loss.

In step S25, the control device 3 determines whether or not the return loss measurement under all the measurement conditions has been completed. Then, if there is a condition that has not been measured among the 20 types of measurement conditions, the process returns to step S23, and if the measurement under all the measurement conditions has been completed, the process ends.

Therefore, when measuring the return loss of the device under test 5, the calibration data stored in the memory 31 is read, and the return loss is obtained from the calibration data and the value measured by the level meter LM1. Therefore, if the calibration data acquisition process shown in FIG. 5 is performed once and the data is stored in the memory 31, only the return loss measurement process shown in FIG. 6 can be continuously performed. As a result, the step of measuring the return loss is greatly reduced, and the return loss can be measured efficiently and in a short time.

In particular, when the return loss is measured for a plurality of devices under test 5, if the calibration data is stored in the memory 31, only the return loss measurement process of FIG. It can measure very efficiently.

Since the data measured in the calibration data acquisition processing of FIG. 5 is stored in association with the measurement conditions, when measuring the return loss under a plurality of measurement conditions, the data measured under each measurement condition is used. May be read from the memory 31. In addition, since the calibration data is stored in association with the measurement conditions, the reading of the calibration data can be performed quickly. Therefore, the return loss under a plurality of measurement conditions can be measured in a short time, and the efficiency can be further improved.

Further, in the calibration data acquisition processing shown in FIG. 5, calibration data under a plurality of measurement conditions is continuously measured and stored. For this reason, much calibration data can be quickly acquired and stored in the memory 31.

In the return loss measuring apparatus 1, during the calibration data acquisition process shown in FIG.
As a result, the device under test 5 is disconnected, and the device under test 5 is connected to the pseudo line 23 during the return loss measurement process shown in FIG. During the return loss measurement process, step S2
After the communication state is set in step 2, the device under test 5 is continuously supplied with power, so that the supply of power is not stopped or interrupted.
For this reason, since the device under test 5 is kept in a stable operation state, the return loss of the device under test 5 can be measured efficiently and accurately.

In the above embodiment, the oscillation frequency of the oscillator OSC is 0.3 kHz (kilohertz) and 1.
0 kHz, 2.0 kHz, and 3.4 kHz can be set, and the pseudo line 23 has a line with a loss of 0 dB (decibel) and a line length of 0.4.
This example shows five characteristics that can be set: a line with a loss of 3 dB in mm, a line with a loss of 7 dB in a line of 0.4 mm, a line with a loss of 3 dB in a line of 0.65 mm and a line with a loss of 7 dB in a line of 0.65 mm. This is a condition for measuring the return loss in accordance with the standards of the Telecommunications Terminal Function Examination Association, and it is of course possible to set other conditions in the return loss measuring device 1. Further, the device that can set a plurality of states as the measurement condition is not limited to the pseudo line 23 and the oscillator OSC.

Further, the oscillator OSC, the standard terminator 25, and the device under test 5 are all connected to the switching circuit 24. However, the present invention is not limited to this, and a plurality of switching circuits are provided. The configuration may be such that the device connected to the hybrid circuit 21 and the device connected to the pseudo line 23 are switched by a different switching circuit, and the specific power supply voltage can of course be appropriately changed. is there.

[0076]

According to the first and fifth aspects of the present invention, when measuring the return loss, the calibration data stored in the storage means may be read, and the acquisition of the calibration data and the measurement of the return loss are performed as in the related art. There is no need to repeat. For this reason,
By obtaining the calibration data only once in advance, the return loss of a plurality of analog telephone terminal devices can be measured in a short time. As a result, the process and time involved in return loss measurement can be significantly reduced, efficiency can be improved, and work load can be reduced.

According to the second aspect of the present invention, when measuring the return loss under a plurality of measurement conditions, the calibration data corresponding to the relevant measurement conditions may be read from the storage means. Also, since the calibration data is stored in association with the measurement conditions, it can be read out quickly. As a result, the return loss under a plurality of measurement conditions can be measured in a short time, and the efficiency can be further improved.

According to the third aspect of the present invention, since the calibration data under a plurality of measurement conditions is obtained first, the return loss measurement of the analog telephone terminal device can be continuously and quickly performed. In particular, when there are a plurality of analog telephone terminal devices to be measured and the return loss is measured under a plurality of measurement conditions, the time required for the measurement can be greatly reduced, and the measurement can be performed more efficiently and quickly. Further, after the calibration data is continuously obtained, only the return loss measurement can be continuously performed, so that the analog telephone terminal device remains powered during the measurement. Therefore, there is no need to stop or interrupt the power supply to the analog telephone terminal device, and the return loss can be measured while maintaining a stable operation state.

According to the fourth aspect of the present invention, the return loss excluding the influence of the leakage power and the reception loss of the return loss measuring device can be quickly measured, so that the convenience is higher.
A return loss measuring device capable of improving efficiency and reducing the work load can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a return loss measuring device 1 according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a connection state of a measurement unit 2 when acquiring calibration data.

FIG. 3 is a block diagram showing a connection state of a measurement unit 2 when acquiring calibration data.

FIG. 4 is a block diagram showing a connection state of a measurement unit 2 at the time of return loss measurement.

FIG. 5 is a flowchart showing a calibration data acquisition process in the return loss measuring device 1 of FIG.

FIG. 6 is a flowchart showing a return loss measuring process in the return loss measuring device 1 of FIG.

FIG. 7 is a flowchart showing a procedure of a conventional return loss measurement.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Return loss measuring device 2 Measuring part 21 Hybrid circuit 22 Power supply circuit 23 Pseudo-line 24 Switching circuit 25 Standard terminator OSC oscillator LM1 / LM2 Level meter R Resistance 3 Control device 31 Memory 5 Device under test

Claims (5)

[Claims] 1. A return loss measuring device for an analog telephone terminal device, comprising: a calibration unit for acquiring calibration data of the return loss measuring device; a storage unit for storing calibration data acquired by the calibration unit; Measuring means for measuring the return loss of the analog telephone terminal device based on the calibration data stored in the means. 2. The method according to claim 1, wherein the calibration unit acquires calibration data under a plurality of measurement conditions, and the storage unit stores each calibration data acquired by the calibration unit in association with the measurement conditions. Item 2. The return loss measuring device according to Item 1. 3. The return loss measuring device according to claim 2, wherein the calibration means continuously acquires calibration data under the plurality of measurement conditions before the return loss measurement by the measurement means. 4. The return according to claim 1, wherein the calibration data acquired by the calibration means is data indicating a leakage power and a reception loss of the return loss measuring device. Loss measuring device. 5. A method for measuring return loss of an analog telephone terminal device, comprising: a step of acquiring calibration data of a return loss measuring device; a step of storing the acquired calibration data in a storage unit; Measuring the return loss of the analog telephone terminal device based on the obtained calibration data.