JPS6140069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for testing communication cables for disconnection and cross-linking.

In recent years, a method has been developed in which the core wires are taken out one by one in order to automate the disconnection test for multi-pair communication cables, but the processing methods for other terminals are different when performing a disconnection test and when performing a crosstalk test. However, there was a drawback that the core wire had to be taken out twice.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a test method in which a wire breakage test is performed simultaneously in order to remove the core wire only once.

In other words, the gist of the present invention is to send a pulse from one end of the core wire under test of a communication cable, and to instantly check for the presence or absence of disconnection or crosstalk from the one-hour waveform of the reflected voltage, thereby making it possible to simultaneously test for disconnection or crosstalk. This is a test method.

An embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a simultaneous disconnection/crossing tester 2 is connected to a core wire 11 under test of a multi-pair communication cable 1.

In the multi-pair communication cable 1, the core wires 12, 13, .
2', 13', 14', 15',... are insulated.

In the simultaneous disconnection/crossing tester 2, pulses are introduced from a pulse generator 21 to a well-known hybrid transformer 22 (for example, a transformer consisting of a coil as shown in the drawing). A pulse is sent to a pseudo circuit 23 which can be adjusted according to the time, and an unbalanced voltage 22' with respect to time caused by each reflected wave is extracted.

That is, when a step input pulse 31 as shown in FIG. 2 is applied from the pulse generator 21, the pulses are divided into two by the coil and sent to the core wire under test 11 and the pseudo circuit 23, respectively.

If the core wire 11 under test is normal, the core wire end 1
At 1', the pulse wave is reflected and returns to the coil.

On the other hand, in the pseudo circuit 23, a reflected wave is also generated at a normal time and returns to the coil, so that both reflected waves are balanced, and the output 22' of the hybrid transformer 22 becomes as shown in FIG. 234. It becomes a waveform.

Next, if there is a break in the core wire 11, the step input pulse 31 is reflected at the break and returns to the coil early, so a time difference occurs between the reflected wave at the pseudo circuit 23 and the second pulse. This results in an unbalanced voltage waveform as shown in FIG.

In addition, if there is crosstalk in the core wire 11, the step input pulse 31 has no reflected wave at the core wire 11, and
Since a reflected wave occurs only in the pseudo circuit 23, an unbalanced voltage waveform as shown in FIG. 233 is obtained.

Therefore, based on this unbalanced voltage 22', the time axis setting section 24 sets the controllable gate 25 to compare the voltage at this unbalanced voltage waveform part, and the voltage comparison section 26 with the set voltage is used to detect the disconnection. The presence or absence can be determined instantly and at the same time.

Note that the horizontal axis of each waveform in FIG. 2 is a time axis.

According to the present invention, it is possible to perform a disconnection test and a cross-wire test at the same time, which of course eliminates the need to take out the core wire twice in the past, and furthermore, it is possible to significantly shorten the test time and terminal preparation time. Become.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an example of an apparatus configuration for carrying out the communication cable disconnection test method of the present invention, and FIG. 2 is an explanatory diagram showing an example of a response waveform that can withstand the presence or absence of disconnection. 1...Multi-pair communication cable, 2...Simultaneous disconnection/crossing tester, 11, 11', 12, 12', 13, 1
3', 14, 14', 15, 15'... Core wire, 19
...Shield, 21...Pulse generator, 22...
Hybrid transformer, 23...Pseudo circuit network, 2
4... Time axis setting section, 25... Gate, 26...
Voltage comparison section, 31...Input pulse, 32, 33,
34...Unbalanced voltage waveform.

Claims (1)

[Claims] 1. By applying a pulse to the core wire under test of a communication cable and the pseudo-circuit network of this cable, extracting the unbalanced voltage from both, and observing the response waveform of this unbalanced voltage over time, the disconnection and crosstalk can be detected. A communication cable disconnection/crosstalk test method characterized by simultaneous determination.