JP5465743B2 - Optical pulse tester - Google Patents

Description

In the present invention, an optical pulse is incident on an optical fiber, and reflected return light (backscattered light, Fresnel reflected light) returning from the optical fiber is received and signal analysis is performed. More particularly, the present invention relates to an optical pulse tester capable of simplifying the measurement work and reducing the work burden on the measurement operator.

In an optical communication system that realizes a high-speed and large-capacity optical communication system, an optical pulse tester (Optical Time Domain Reflectmeter) is used for the maintenance of the optical fiber that is the communication medium or for the maintenance after the installation. Searches for fiber failure points and loss distribution monitoring.

FIG. 8 is a block diagram showing a basic configuration of a conventional optical pulse tester 100.
In response to the timing signal Et generated by the timing generator 103, the drive circuit 102 generates a drive signal Ed. Upon receiving this drive signal, the pulse light source 101 emits an optical pulse Po to the measured optical fiber 130 connected to the optical connector 105 via the optical directional coupler 104 such as an optical coupler. Then, the backscattered light such as Rayleigh scattered light or the reflected return light Pr such as Fresnel reflected light from the breaking point of the optical fiber is different from the optical path to which the pulse light source 101 is connected via the optical directional coupler 104. The light is received by the light receiver 106 connected to, and is converted into an electric signal corresponding to the light reception level. The A / D converter 107 sequentially converts the electrical signal output from the light receiver 106 into a digital signal at a constant sampling interval at the timing of the timing signal Et of the timing generator 103.

The digital signal is stored in the waveform data memory 108 as measurement data in which the distance of the optical fiber to be measured from the optical connector 105 and the reflection level from each distance position are associated with each other.
The display data generation unit 110 creates the loss distribution waveform data 110a for displaying the waveform on the display screen 113 and the event list data 110b for displaying the measurement result in a tabular format based on the measurement data, and the display control unit 111 displays either the loss distribution waveform or the event list selected by the display changeover switch 112 on the display screen 113 as a measurement result.

FIGS. 9 and 10 are examples schematically showing a state in which the loss distribution waveform and the event list are displayed on the display screen 113 of the optical pulse tester 100, respectively.
In FIG. 9, the rectangular display screen has the long side down, the horizontal axis is the distance from the optical connector 105 of the optical fiber 130 to be measured, and the vertical axis is the level of the reflected return light Pr, that is, the optical fiber 130 to be measured. A loss distribution waveform 118 is displayed as a loss level at each distance from the optical connector 105.

If there is no bending or breakage in the optical fiber, only reflected return light based on Rayleigh scattered light exists and the loss distribution waveform becomes a straight line with a downward slope, but in the example of FIG. 9, loss due to bending of the optical fiber Reflection due to optical fiber breakage and connector connection, and Fresnel reflection at the end of the optical fiber are observed as inflection points 118a, 118b, and 118c, respectively.
In the outer frame of the display screen 113, various operation buttons, for example, a START button 115 for starting measurement and a display changeover switch 112 for switching display of the loss distribution waveform and the event list are arranged. In the example of FIG. The display changeover switch 112 is pressed to switch to the event list display.

In FIG. 10, the event list 119 is displayed with the long side of the display screen as the height direction.
In the left column of the event list 119, for example, identification numbers 119a for identifying various events 118a to 118c appearing in the loss distribution waveform in FIG. 9 are shown. In the middle column and the right column, the distance 119b of each event and the loss Level 119c is displayed. The reason that the event list 119 is displayed with the long side of the display screen 113 as the height direction is that the measurement results can be confirmed without scrolling or the like for more events at a time.
The display of the event list 119 is switched to the loss distribution waveform by pressing the display changeover switch 112.

Japanese Patent Laid-Open No. 2001-21451

In general, the event list automatically detects events with the auto search function, and the list is displayed in order, reducing the work load on the measurer. On the other hand, the auto search function is not universal. There may be a case where an event is erroneously detected or not detected. At that time, the measurer switches the display to the loss distribution waveform with the display changeover switch, and tilts the main body of the optical pulse tester so that the display screen is in landscape orientation, and then visually confirms the presence of the event with the loss distribution waveform. After that, the operation of pressing the display switch again to switch the display to the event list and tilting the optical pulse tester is repeated, but each time the display is switched, the display switch is pressed to tilt the optical pulse tester. It was forced to repeat the operation, and it was cumbersome for the measurer.

In view of the above problems, an object of the present invention is to provide an optical pulse tester capable of reducing the operation burden of a measurer who switches the display of a loss distribution waveform and an event list and confirms a measurement result. To do.

In order to achieve the above object, according to the first aspect of the present invention, the pulsed light P0 is emitted to the measured optical fiber 130, and the loss distribution characteristic of the measured optical fiber is based on the reflected return light Pr from the measured optical fiber. Either the loss distribution waveform that represents the loss distribution characteristics with the two axes of the distance and loss level of the optical fiber to be measured, or the event list that represents the loss component characteristics with a two-column list of the distance and loss level of the optical fiber to be measured In the optical pulse tester that selectively displays the image on the display screen, the gravity detection unit 4 that detects the gravity direction G and the first axis Lx parallel to the display screen and the angular difference between the gravity direction A direction detection unit 5 that detects an angle difference θx of 1, a second axis Ly that is perpendicular to the first axis and parallel to the display screen, and a second angle difference θy that is an angle difference between the gravitational directions; The event list is displayed on the display screen. In the displayed state, when the first angle difference is equal to or smaller than the first angle αx, the loss waveform is selected, and in the state where the loss distribution waveform is displayed on the display screen, the second angle difference is the second angle. a display determination unit 6 that selects an event list when αy or less, and when the display determination unit selects a loss distribution waveform, the loss distribution waveform is displayed with the axis direction of the loss level as the first axis. When the display determination unit selects an event list, the event list is displayed on the display screen with the column direction of the list being the direction of the second axis.

To achieve the above object, according to a second aspect of the present invention, in the optical pulse tester according to the first aspect, the display screen is substantially rectangular and the first axis is parallel to the short side of the display screen. It is characterized by.

In order to achieve the above object, the invention according to claim 3 is characterized in that pulse light is emitted to the optical fiber to be measured, and the loss distribution characteristic of the optical fiber to be measured is measured based on the reflected return light from the optical fiber to be measured. Displays either the loss distribution waveform that shows the loss distribution characteristics with the two axes of the measured optical fiber distance and loss level, or the event list that shows the loss characteristics as a two-column list of the measured optical fiber distance and loss level. In the display method of the optical pulse tester selectively displayed on the screen, a step of detecting the gravity direction G and a first angle which is an angle difference between the first axis Lx parallel to the display screen and the gravity direction Detecting a difference θx, a second axis Ly that is perpendicular to the first axis and parallel to the display screen, and a second angle difference θy that is an angle difference between the gravity directions, and an event list on the display screen In the state where is displayed, When the angle difference of 1 is equal to or less than the first angle αx, the loss angle waveform is selected, and the loss distribution waveform is displayed on the display screen, the second angle difference is equal to or less than the second angle (αy). When selecting the event list, and when the loss distribution waveform is selected, the loss distribution waveform is displayed on the display screen with the axis direction of the loss level as the first axis, and when the event list is selected, the list of the list is displayed. The event list is displayed on the display screen with the column direction as the direction of the second axis.

  According to the present invention, since it is possible to alternately switch the display of the loss distribution waveform and the event list by tilting the optical pulse tester main body, the pressing operation of the display changeover switch, which has been conventionally required, is omitted, and measurement is performed. The work burden on the person can be reduced.

It is a block diagram which shows the structure of the optical pulse tester which concerns on this invention. It is a figure for demonstrating the positional relationship of the optical pulse tester which concerns on this invention, and gravity. It is a figure for demonstrating a gravity detection part. It is a figure for demonstrating the relationship between gravity and a display screen. It is a figure for demonstrating switching of the display to a loss distribution waveform. It is a figure for demonstrating switching of the display to an event list. It is a figure for demonstrating switching of the display of a loss distribution waveform and an event list. It is a block diagram which shows the structure of the conventional optical pulse tester. It is a figure for demonstrating the display of the loss distribution waveform in the conventional optical pulse tester. It is a figure for demonstrating the display of the event list | wrist in the conventional optical pulse tester.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a block diagram showing an internal configuration of an optical pulse tester 1 according to the present invention. The same components as those of the conventional optical pulse tester 100 are denoted by the same reference numerals.
In this embodiment, instead of the display changeover switch 112 in the conventional optical pulse tester 100, the gravity detection unit 4, the direction detection unit 5, and the display determination unit 6 perform a screen display switching function.

In this optical pulse tester, an optical pulse Po emitted from a pulse light source 101 in response to a drive signal Ed from a drive circuit 102 is connected to an optical connector 105 via an optical directional coupler 104 such as an optical coupler. The reflected return light Pr emitted to the optical fiber 130 is received by the light receiver 106 connected to an optical path different from the optical path to which the pulse light source 101 is connected, and converted into an electrical signal. The electrical signal output from the light receiver is converted into digital data by the A / D converter 107 and stored in the measurement data memory 108 as measurement data.

The display data generation unit 110 generates loss distribution waveform data 110a and event list data 110b, which are display data for displaying the measurement results on the display screen 113, based on the data stored in the measurement data memory 108.

The gravity detection unit 4 is, for example, an acceleration sensor mounted on a printed circuit board inside the optical pulse tester, and detects the direction of the ground as viewed from the optical pulse tester 1, that is, the gravity direction G.

The direction detection unit 5 calculates the angle of the display screen 113 with respect to the ground based on the gravity direction G detected by the gravity detection unit 4.

The display determination unit 6 determines which of the long side and the short side of the rectangular display screen 113 is upward from the inclination angle of the display screen 113 detected by the direction detection unit 5, that is, the display screen is lateral to the ground. It is determined whether the optical pulse tester is held or held vertically. When the display screen 113 is in landscape orientation, the display of the loss distribution waveform is selected. When it is determined that the display screen 113 is in portrait orientation, the event list is selected. Is displayed and the display control unit 111 is instructed.

The display control unit 111 displays the measurement result of the selected display format on the display screen 113 according to the instruction of the display determination unit 6.

Based on FIGS. 2-7, an example of the process from detection of the gravity direction G to selection of a display format is explained in full detail.
2 shows the gravity detector 4 mounted on the optical pulse tester 1, the first axis Lx parallel to the display screen 113 and parallel to the short side of the display screen 113, and the display screen 113. The positional relationship between the optical pulse tester 1 and the second axis Ly that is parallel and parallel to the long side of the display screen 113, that is, that is perpendicular to the first axis Lx is shown.

The gravity detection unit 4 is, for example, an acceleration sensor, which is installed on a printed circuit board 10 mounted inside the optical pulse tester as shown in FIG. 3, and detected in accordance with the inclination of the optical pulse tester. The direction of gravity G is detected from the direction of (4x, 4y, 4z).

FIG. 4A is a diagram showing the positional relationship between the gravity direction G detected by the acceleration sensor and the first axis Lx and the second axis Ly. The direction detection unit 5 is detected by the gravity detection unit 4. Based on the gravity direction, the angle difference θx between the first axis Lx and the gravity G and the angle difference θy between the second axis Ly and the gravity G are calculated.

FIG. 4B is a diagram showing the positional relationship between the first axis Lx and the gravity direction G viewed from the AA direction in FIG. 4A, and FIG. 4C is the diagram in FIG. It is a figure which shows the positional relationship of the 2nd axis | shaft Ly and the gravity direction G seen from the BB direction.

With the event list 119 displayed on the display screen 113, the display controller 6 changes the first axis Lx calculated by the direction detector as shown in FIG. When the angle difference θx with respect to the gravity direction G is equal to or less than the arbitrarily set angle αx, it is determined to switch to the loss distribution waveform instead of the event list, and the display control unit 111 selects FIG. As shown, the loss distribution waveform 118 is displayed on the display screen 113 in the horizontal direction.

In addition, the display control unit 6 sets the second axis Ly according to the inclination of the optical pulse tester 1 in a state where the loss distribution waveform 118 is displayed on the display screen 113, as shown in FIG. When the angle difference θy with respect to the gravitational direction G is less than or equal to an arbitrarily set angle αy, it is determined to switch the display to the event list 119, and the display control unit 111 displays the display as shown in FIG. An event list 119 is displayed on the screen 113 in the vertical direction.

As described above, the optical pulse tester 1 according to the present invention alternately switches the display of the loss distribution waveform 118 and the event list 119 based on the inclination of the main body with respect to gravity as shown in FIG. The display changeover switch 112 for changing the display of the loss distribution waveform 118 and the event list 119, which was essential in the tester 100, is unnecessary, and it is possible to reduce the work load of the measurer who presses the display changeover switch. did.

DESCRIPTION OF SYMBOLS 1,100 ... Optical pulse tester 4 .... Gravity detection part 5 .... Direction detection part 6 .... Display determination part 10 .... Printed circuit board 101, Pulse light source 102 ... Driving circuit 103 ... Timing generator, Et ... Timing signal, Ed ... Drive signal, 104 ... Optical directional coupler, 105 ... Optical connector, 106 ... Photo detector, 107 ... A / D converter, 108 ... Measurement data memory, 110... Display data generation unit, 110 a .. Loss distribution waveform data, 110 b .. Event list data, 111... Display control unit, 112... Display changeover switch, 113. Loss distribution waveform, 119 ... Event list, 130 ... Optical fiber G to be measured G ... Gravity, Po ... Light pulse, Pr ... Reflected return light

Claims (3)

Pulse light (Po) is emitted to the measured optical fiber (130), the loss distribution characteristic of the measured optical fiber is measured based on the reflected return light (Pr) from the measured optical fiber, and the loss distribution characteristic is measured. A display screen that displays either a loss distribution waveform that represents the measured optical fiber distance and loss level on two axes or an event list that represents the loss characteristics as a two-column list of the measured optical fiber distance and loss level In the optical pulse tester that selectively displays
A gravity detector (4) for detecting the direction of gravity (G);
A first angle difference (θx) that is an angle difference between the first axis (Lx) parallel to the display screen and the gravity direction, and perpendicular to the first axis and parallel to the display screen A direction detector (5) for detecting a second angle difference (θy) that is an angle difference between the second axis (Ly) and the gravity direction;
In a state where the event list is displayed on the display screen, when the first angle difference is equal to or smaller than a first angle (αx), the loss waveform is selected, and the loss distribution waveform is displayed on the display screen. And a display determination unit (6) that selects the event list when the second angle difference is equal to or smaller than a second angle (αy).
When the display determination unit selects a loss distribution waveform, the loss distribution waveform is displayed on the display screen with the axis direction of the loss level being the first axis direction, and the display determination unit selects an event list Sometimes, the event list is displayed on the display screen with the column direction of the list being the direction of the second axis. 2. The optical pulse tester according to claim 1, wherein the display screen is substantially rectangular, and the first axis is parallel to a short side of the display screen. Pulse light is emitted to the optical fiber to be measured, the loss distribution characteristic of the optical fiber to be measured is measured based on the reflected return light from the optical fiber to be measured, and the loss distribution characteristic is determined as the distance of the optical fiber to be measured. An optical pulse test that selectively displays either a loss distribution waveform represented by two axes of loss levels or an event list representing the loss characteristics as a two-line list of the measured optical fiber distance and loss level on a display screen In the display method of the vessel,
Detecting the direction of gravity (G);
A first angle difference (θx) that is an angle difference between the first axis (Lx) parallel to the display screen and the gravity direction, and perpendicular to the first axis and parallel to the display screen Detecting a second angle difference (θy) that is an angle difference between the second axis (Ly) and the gravity direction;
In a state where the event list is displayed on the display screen, when the first angle difference is equal to or smaller than a first angle (αx), the loss waveform is selected, and the loss distribution waveform is displayed on the display screen. When the second angle difference is equal to or smaller than a second angle (αy), the event list is selected.
When the loss distribution waveform is selected, the loss distribution waveform is displayed on the display screen with the axis direction of the loss level being the direction of the first axis, and when the event list is selected, the column direction of the list is A display method for an optical pulse tester, characterized in that the event list is displayed on the display screen in the direction of a second axis.

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