DE102005018865A1 - Method and apparatus for measuring using a main and a remote unit - Google Patents

Abstract

A test instrument uses a main and a remote test unit at respective ends of a cable being tested. The units operate in an active or passive measurement mode, with one of the units starting as an active unit, applying test signals to the cable under test to make a set of measurements associated therewith, while the other unit measures on the basis of the first End applied signals. After a set of measurements has been completed, the units then interchange the roles and the original passive end becomes the active end, applying test signal stimuli, while the original active end now becomes passive and a series of corresponding measurements based on the test distance of active end. The measurements are thereby overlapped and carried out from both ends of the cable, which saves time.

Description

background the invention

These Invention relates to the test and measurement and in particular network cable testing.

A quick exam time is in the cable test important in local area networks (LAN), as in a special audit scenario 36 individual frequency response measurements each with 1168 test frequencies over one Range from 1 to 600 MHz must be performed. These considerable Number of exams may require a significant amount of time to complete. A Method to increase the measuring time So far, it has been to use a system in simultaneous measurements by providing two different ones Check signals different conductor pairs of a cable are performed, with two different not disturbing oneself test frequencies be used, the frequencies are offset, so that the first test signal and the second test signal Do not disturb the special respective other exam. These Art System imposes the test, the same time can be restrictions because the requirement does not comply with disturbing frequencies must become.

Summary the invention

According to the invention a main and a remote test module work together, with a Module, for example, the main module, acts to test signals and to provide measurements while the other module, in this case the remote, takes measurements at the same time Time like the main module at the test license, which is supplied by the main module performs. A series of tests will be carried out, whereupon the main module and the remote module exchange the functions can, so that then removed module the test signal and performs a series of measurements while the main module performs the various exams based on the signal stimulus from the remote module. A larger number of exams This can be done in a given period of time.

consequently It is an object of the present invention to provide an improved test instrument to enable an improved exam time provide.

It Another object of the present invention is an improved one Method of testing a network cable that uses time more efficiently.

It is yet another object of the present invention, an improved System and method for testing of network cables.

Of the The subject of the present invention is in the final part This description particularly highlighted and clearly claimed. Either the organization as well as the procedure of the company together with However, other benefits and tasks thereof can best be achieved by Reference is made to the following description taken in conjunction with the accompanying drawings be understood, in which like reference numerals to like elements Respectively.

Summary the drawings

1 is a diagram of main components of a test instrument according to the invention;

2 is the test instrument of 1 which is adapted to perform a reference path measurement;

3 is the test instrument of 1 wherein a NEXT measurement is performed;

4 is the test instrument of 1 wherein an error attenuation measurement is performed;

5 Figure 12 is a diagram of the main and remote instruments when connected to a tested cable;

6 FIG. 12 is a diagram illustrating exemplary measurements performed by the main and remote devices in a preferred embodiment and their timing.

Full description

The System according to one preferred embodiment of the present invention comprises a Netzwerkprüfinstrument for testing from LAN cables. A tester for cables For example, four line pairs are provided.

Regarding 1 , a circuit diagram showing the configuration of the test instrument 10 are four pairs of cables 12 . 12 ' . 12 '' and 12 ''' via respective baluns 14 with switches 16 connected to a test signal transmission switch 16a , one Test signal-receive switch 16b and a communication transmission switch 16c (not shown). The transmission switch 16a receives test signals from the measuring signal source 18 while the reception desk 16b with the receiver 20 connect, which includes a receiver and Impulsrauschvergleicher in the illustrated embodiment.

Between the receiver 20 and the measuring signal source 18 there is a return path system 26 that has a directional coupler 26a and switches 26 comprising, wherein a switch 26b the receiver input connects to the directional coupler, another switch 26c the receiver input with a third switch 26d couples with the signal source 18 and with the transmitters 16a is connected, and in the preferred embodiment has a signal attenuation of -20 dB. The directional coupler is between the signal source 18 and the entrance to the receiver 20 and also has a signal attenuation of -20 dB.

A DSP / a CPU 24 is also conveniently provided and coupled with the various components of the instrument to receive and process data, send data and control and operate the inspection operations.

With reference now to 2 is the test instrument of 1 designed to perform a reference path measurement, where the instrument is calibrated, etc. In this configuration, the switches are 16 all open and the switches 26c and 26d are closed ( 26b is open), whereupon test signals are supplied from the signal source directly to the receiver.

In 3 For example, the instrument is designed to perform close-up crosstalk on cable pairs 1 and 2 (NEXT 1,2). Here are the switches 16a and 16b ' closed so that the test signal from the signal source 18 is sent on the cable pair 1 and the received information from the cable pair 2 is supplied to the receiver.

4 shows the switch configuration for measuring the error attenuation on the cable pair 1, wherein the transmit switch 16a closed is ( 16b . 16c (not shown) are open), 26b closed is ( 26c and 26d are open). In this configuration, the test signal is from the signal source 16 supplied to cable pair 1 and a reflected signal is received from the receiver 20 over the directional coupler 26a added.

Having observed some specific switch configurations for enabling certain measurements, the timing and various tests performed in the preferred embodiment are in conjunction with FIG 5 , a diagram illustrating the configuration of the main and the remote instrument, and with reference to FIG 6 to see the exemplary measurements performed by the main and the remote device and their timing in a preferred embodiment.

In operation, the instrument uses a first instrument part at one end of a tested cable 32 and a second instrument part 34 at the opposite end of the cable. The two parts 30 . 34 alternate between working as source end and non-source ending. Thus, in the upper part of 5 the instrument part 30 the source end, while the part 34 the non-source end is, and in the lower part of 5 have the two reversed roles, so that the instrument part 34 now the source end is and the part 30 the non-source end is. This operation allows a complete set of measurements to be made from both ends of the cable.

Regarding 6 For example, the measurements are made simultaneously by the source and non-source ends, with the measurement set 36 the source end detail is and the timing and measurement set 38 the detail and timing of the non-source end is. The measurements are subdivided into time slots, where the source end in a first time slot is a reference path measurement (which is used in conjunction with 2 previously discussed) to calibrate the device for other tests. The non-source unit does not take measurements in this time slot since no test signal is yet applied to the cable being tested. In the following slot, the source unit measures NEXT 1.2 (close crosstalk of cable pairs 1 to 2) while the non-source unit measures FEXT 1.3 (far crosstalk of cable pair 1 to 3), taking advantage of the test signal applied by the source unit power. In the following slot, near end crosstalk of cable pair 1 to 3 is measured by the source unit and FEXT 1,2 is measured by the non-source end. Thereafter, the source end applies a test signal to measure NEXT 1.4 (the transmit switch 16a is closed to apply the test signal to cable pair 1, and the receive switch 16b ''' is closed to receive the return crosstalk on the cable pair 4). In this time slot, the non-source unit measures the insertion loss of cable pair 1 (IL 1), which provides end-to-end transmission loss of the cable.

Next, the source unit performs an error attenuation measurement on cable pair 1 (RL 1) by determining the ratio of the reflected signal to the incident signal, while the Non-source uses the test signal provided by the source to measure far-end crosstalk from cable pair 1 to 4 (FEXT 1,4). The measurement continues with the source end NEXT 2, 3; NEXT 2,4; RL 2; NEXT 3.4 and RL 3, while the corresponding sequence for the non-source end FEXT 2.4; IL 2; FEXT 2.3; IL 3 and FEXT is 3.4.

In the slot corresponding to the RL3 source and FEXT3.4 non-source measurement slot follows, the source has a slot in which no measurement of this End takes place while the non-source end the insertion loss of cable pair 4 (IL 4). Then in the following slot the source measurement RL4 (error attenuation of the Cable pair 4) instead of while the non-source end is in passive termination mode, with a passive termination impedance from 100 ohms to the tested cable is created. The next 4 slots at the source end are Ruhe 1, Ruhe 2, Ruhe 3 and Ruhe 4, while the non-source end the slits has quiet 4, rest 3, rest 2 and rest 1. In each of these Slots observe both the source end and the non-source end at rest the signal source from the test instrument is turned off, and measurements are made on the particular cable pair (e.g., measures REST 1 cable pair 1, REST 2 measures cable pair 2, etc.) determine whether any electromagnetic interference or other There is noise caused by an external source could.

After the test sequence described above has ended, the source and non-source ends are now interchanged so that the end 34 now the source end is and the check slot sequence 36 performs while the end 32 which was the source end before, now becomes the non-source end, that is the probe slot sequence 38 performs. In this way, the sequences of tests are performed from each end of the cable.

Still referring to 6 a particular detail of the measurement of a slot sequence is shown, in this case the slot NEXT 2, 3 of the source unit. The particular slot begins with a gain adjustment section which, in the illustrated embodiment, lasts for 64 μs, so that the instrument gain is adjusted to an appropriate level. Next, a set of N measurements is made at 64 μs to provide an averaging capability, where N is the averaging factor.

The above-described operations are performed by the CPU 24 in the respective source and non-source unit 30 and 34 controlled. The units communicate with each other via the cable pairs of the cable under test using a circuit, not shown, to exchange data for synchronizing the start of the measurements, the measurement results, fault conditions, and the like. The various switches are all controllable by the CPUs in the respective units.

According to the invention Consequently, measurements are made simultaneously on both ends of a cable being tested carried out, being an active audit permit is provided at one end and measurements related to the stimulus, be done at this end, while at the other end passive measurements using the test signals performed from the first end become. After a series of measurements have been made, the two ends interchange the rollers and the measurements of the active one Endings are now from the original one second end performed and the measurements of the passive end are made at the end that first the active end was.

Even though a preferred embodiment It has been shown and described in the present invention for professionals you can see that many changes and modifications can be made without departing from the invention to deviate in their broader aspects. The appended claims are intended therefore all such changes and modifications that are within the true thought and scope fall of the invention, capture.

Claims (12)

Method for operating a test instrument to perform of measuring operations at a tested Cable comprising: Providing a first module for coupling with a first end of a cable to provide a test index to this and to performing of measurements; and Providing a second module for coupling with a second end of the cable for making measurements on the Basis of the stimulus provided by the first module. The method of claim 1, wherein the second module the measurements in coordination with the stimulus and the measurement time course of the first module. The method of claim 1, further comprising performing Take measurements with the first and second modules by supplying one Test codes from first module and based on the measurement thereon. The method of claim 3, wherein the second module is also provided with the capability to provide a test clearance to the cable being tested and Mes to carry out this work. The method of claim 4, further according to Carry out measurements based on the stimulus provided by the first module supplying a stimulus from the second module and performing Measurements from the first and second modules based on it includes. The method of claim 1, wherein the measuring operations of the first module selected from the group consisting of near-end crosstalk and error damping consists. Method according to claim 6, wherein the measuring operations of the first module further comprise measurements of the electromagnetic interference. The method of claim 1, wherein the measuring operations of the second module are selected from the group consisting of far-end crosstalk, return loss and electromagnetic interference consists. The method of claim 8, wherein the measuring operations of the second module further comprise electromagnetic interference measurements. The method of claim 1, wherein the second module is designed to provide a passive termination on the tested cable. test instrument With: a first inspection license and measuring module, which is designed to be coupled to a first end of a cable under test; one second test approval and measuring module, which is designed to be coupled to a second end of the cable under test; in which the test instrument used a first mode in which the first test module a Stimulus to cable supplies and measurements based on the stimulus of first module, while the second test module simultaneously measurements based on the stimulus from the first module and over time with the stimulus from the first module. test instrument according to claim 11, wherein the test instrument further uses a second mode in which the second test module a Stimulus to the cable supplies and measurements based on the stimulus forward second module, while the first test module simultaneous measurements based on the stimulus from the second module and over time with the stimulus from the second module.