CN2436941Y

CN2436941Y - Fault dectecting instrument for communication line

Info

Publication number: CN2436941Y
Application number: CN00215683U
Authority: CN
Inventors: 李坤
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-27
Filing date: 2000-07-27
Publication date: 2001-06-27
Anticipated expiration: 2010-07-27

Abstract

The utility model discloses a fault detecting instrument for telecommunication lines, which comprises a line inspecting machine, a wiring terminal, a range switch, a data measuring circuit, a D/A conversion circuit and a display device, wherein the wiring terminal is connected with a static contact of the range switch, the line inspecting machine and the data measuring circuit are respectively connected to two moving contacts, and the data measuring circuit comprises a resistance measuring circuit which is connected with the input end of the D/A conversion circuit by a changeover switch, a voltage measuring circuit, a short circuit distance measuring circuit and an open circuit distance measuring circuit. Fault points in the lines can be visually and accurately judged by measuring the resistance and the capacitance values of the faulty lines, therefore the utility model provides a cheap and easily used tool for the maintenance of outdoor communication lines.

Description

The telecommunication line fault locator

The utility model relates to electrical communication technology, particularly a kind of telecommunication line fault locator.

Generally can only lean on technician's experience to cooperate line inspection machine (miniature phone machine) to judge the cable that breaks down for the short circuit of outdoor circuit in the communication line and opening circuit property fault, judge that certain a pair of cable breaks down the back owing to can not determine the trouble spot, can't keep in repair, need also a pair of on the line heart yearn to replace the cable that breaks down, because the outdoor communication cable is all very long usually, changes cable and will cause great waste.For the cable that damages is keeped in repair, just must there be a kind of instrument to teach and measures the trouble spot that cable breaks down exactly.

The purpose of this utility model provides the telecommunication line fault locator of the trouble spot of a kind of open circuit of the heart yearn that can judge communication cable more exactly or short circuit.

For achieving the above object, the technical solution adopted in the utility model is as follows:

Telecommunication line fault locator described in the utility model comprises line inspection machine and connection terminal, it also comprises waver, the DATA REASONING circuit, D/A converting circuit and display device, connection terminal is connected on the fixed contact of waver, line inspection machine and DATA REASONING circuit are connected on two moving contacts, the DATA REASONING circuit comprises the resistance measuring circuit that is connected with the input end of D/A converting circuit by a switch, tension measuring circuit, the short circuit range-measuring circuit, range-measuring circuit opens circuit, the input end of D/A converting circuit is connected on the fixed contact of waver, resistance measuring circuit, tension measuring circuit, the short circuit range-measuring circuit, the range-measuring circuit that opens circuit is connected on the different moving contacts, and the output terminal of D/A converting circuit is connected with display device.

As to further improvement of the utility model, described short circuit range-measuring circuit comprises the short-circuit signal processing module that is connected between resistance value circuit and the D/A converting circuit.

As further improving of the present utility model, described short-circuit signal processing module comprises the negative-feedback circuit that is made of operational amplifier and peripheral circuit thereof and is connected the wave filter of its input end and output terminal.

As further improving of the present utility model, the described range-measuring circuit that opens circuit comprises the chopping signal processing module that is connected between electric capacity value circuit and the D/A converting circuit.

As further improving to of the present utility model, described chopping signal processing module comprises the negative-feedback circuit that is made of an operational amplifier and one 555 timers and peripheral circuit thereof, 555 timers and peripheral circuit thereof constitute multi-harmonic-oscillations, and its 5th pin connects the output terminal of operational amplifier by resistance.

After adopting technique scheme, can tentatively judge whether to exist fault, further the heart yearn of opening circuit property of existence fault be measured its electric capacity again, the distance of the big or small failure judgement point by its electric capacity by the operating voltage of measuring cable cores; The heart yearn that has the short-circuit fault is measured its resistance value, the distance of the big or small failure judgement point by its resistance value.

Further specify the utility model below in conjunction with drawings and Examples:

Fig. 1 is the block scheme of an embodiment of the present utility model;

Fig. 2 is the electrical schematic diagram of the short circuit range-measuring circuit among the embodiment of Fig. 1;

Fig. 3 is the electrical schematic diagram of the short-circuit signal processing module among the embodiment of Fig. 1;

Fig. 4 is the electrical schematic diagram of the range-measuring circuit that opens circuit among the embodiment of Fig. 1;

Fig. 5 is the electrical schematic diagram of the chopping signal processing module among the embodiment of Fig. 1;

Principle of work of the present utility model is based on the telecommunication cable that breaks down to be had only short circuit usually and opens circuit two kinds of situations, and can have certain resistance value and electric capacity respectively in a pair of cable of generation both of these case, and the size of resistance value and electric capacity is directly proportional with the length of cable, is specifically to be directly proportional with the distance of measurement point to the trouble spot.

As shown in Figure 1, telecommunication line fault locator described in the utility model comprises line inspection machine 1, connection terminal, it also comprises waver, the DATA REASONING circuit, D/A converting circuit 6 and display device 7, connection terminal is connected on the fixed contact of waver, line inspection machine 1 and DATA REASONING circuit are connected on two moving contacts, the DATA REASONING circuit comprises the resistance measuring circuit 2 that is connected with the input end of D/A converting circuit 6 by a switch, tension measuring circuit 3, short circuit range-measuring circuit 4, range-measuring circuit 5 opens circuit, the input end of D/A converting circuit 6 is connected on the fixed contact of waver, resistance measuring circuit 2, tension measuring circuit 3, short circuit range-measuring circuit 4, the range-measuring circuit 5 that opens circuit is connected on the different moving contacts, and the output terminal of D/A converting circuit 6 is connected with display device 7.

During use, judging on telephone exchange and the trouble-free basis of telephone set, disconnect telecommunication cable and telephone wire at the coupling box place, the waver of this telecommunication line fault locator is pushed the position of DATA REASONING circuit, switch is pushed the position of voltage measurement, whether the voltage at measuring circuit two ends is normal, is transformed into the monitoring of line inspection machine again and has or not telephone dial tones, judges whether telecommunication cable has fault.As be strictly that telecommunication cable has fault, and waver can be pushed the position of DATA REASONING circuit, and switch is pushed the position of resistance measurement, as the resistance of measuring is zero or very little, then can conclude to have the short-circuit fault in the circuit; As the resistance of measuring for infinitely great or, then can conclude to have opening circuit property fault in the circuit; When having the short-circuit fault in the circuit, switch can be pushed the position of short circuit range-measuring circuit, extrapolate trouble spot in the circuit and the distance between the measurement point by the resistance value of measuring.When having opening circuit property fault in the circuit, switch can be pushed the range-measuring circuit that opens circuit, extrapolate trouble spot in the circuit and the distance between the measurement point by the capacitance of measuring failure cable.

Resistance measuring circuit 2 in the present embodiment and voltage measurement 3 circuit adopt is circuit in the common multimeter, is not described in detail in this.

As shown in Figure 2, short circuit range-measuring circuit 4 comprises the short-circuit signal processing module 8 that is connected between resistance value circuit 10 and the D/A converting circuit 6.Resistance value circuit 10 can be the constant flow method resistance measuring circuit in the common multimeter, this circuit produces a constant electric current, when flowing through testee, this electric current produces certain voltage at its two ends, this voltage is delivered to the input end of short-circuit signal processing module 8, short-circuit signal processing module 8 is handled the back to it and is produced a metastable signal, by D/A converting circuit 6 and display device 7 reading is shown intuitively again.

Short-circuit signal processing module 8 as shown in Figure 3 comprises the negative-feedback circuit that is made of operational amplifier IC1 and peripheral circuit thereof and is connected the wave filter 11 of its input end and output terminal.The effect of this partial circuit is by sending display device 7 outputs after the voltage signal filtering clutter steady that has clutter of negative feedback with 10 outputs of resistance value circuit.When the voltage signal of resistance value circuit 10 outputs is unstable, the inverting input of this signal input operational amplifier IC1, amplify after resistance R 7, R2 feed back to the inverting input of operational amplifier IC1 through operational amplifier, form the negative feedback of signal, play the effect of stabilization signal.The input end of negative-feedback circuit and output terminal also are connected with wave filter.

As shown in Figure 4, the range-measuring circuit 5 that opens circuit comprises the chopping signal processing module 9 that is connected between electric capacity value circuit and the D/A converting circuit 6.Electric capacity value circuit can adopt the capacitance measurement circuit in the common multimeter, and this capacitance measurement circuit is made up of 5 operational amplifiers.Operational amplifier A 1, A2 forms a constant ac signal which, produce a constant ac voltage signal at its two ends during this signal process measured capacitance, this signal process is by operational amplifier A 3, after the amplifying circuit that A4 forms amplifies, deliver to the signal input part of chopping signal processing module 9 through resistance R 16, make the signal of operational amplifier A 4 output become corresponding to failure cable length, stable ac voltage signal shows reading to delivering to D/A converting circuit 6 and display device 7 after operational amplifier A 5 is done the adjustment of alternating current-direct current conversion of signals intuitively through R6 then.

As shown in Figure 5, chopping signal processing module 9 comprises the negative-feedback circuit that is made of an operational amplifier IC2 and one 555 timer IC3 and peripheral circuit thereof, 555 timer IC3 and peripheral circuit thereof constitute multi-harmonic-oscillations, and its 5th pin connects the output terminal of operational amplifier IC2 by resistance R 3.Arrive the inverting input of operational amplifier IC2 when the signal of sending from electric capacity value circuit, amplify after resistance R 3 is delivered to the 5th pin of 555 timers, by resistance R 9, triode D9, diode D4, D5, resistance R 10 constitutes a negative-feedback circuit, by triode D8, diode D2, D3 constitutes another negative-feedback circuit, because the effect of two-stage negative-feedback circuit, make with 555 timer IC3 to be that the output signal of the multi-harmonic-oscillations of core changes with the variation of the input signal of operational amplifier IC2, but its output valve is relatively stable, metastable signal is delivered to display device 7 through D/A converting circuit 6 promptly can obtain more stable reading.

Claims

1, a kind of telecommunication line fault locator, comprise line inspection machine (1) and connection terminal, it is characterized in that: it also comprises waver, the DATA REASONING circuit, D/A converting circuit (6) and display device (7), connection terminal is connected on the fixed contact of waver, line inspection machine (1) and DATA REASONING circuit are connected on two moving contacts, the DATA REASONING circuit comprises the resistance measuring circuit (2) that is connected with the input end of D/A converting circuit (6) by a switch, tension measuring circuit (3), short circuit range-measuring circuit (4), range-measuring circuit (5) opens circuit, the input end of D/A converting circuit (6) is connected on the fixed contact of waver, resistance measuring circuit (2), tension measuring circuit (3), short circuit range-measuring circuit (4), the range-measuring circuit (5) that opens circuit is connected on the different moving contacts, and the output terminal of D/A converting circuit (6) is connected with display device (7).

2, telecommunication line fault locator according to claim 1 is characterized in that: described short circuit range-measuring circuit (4) comprises the short-circuit signal processing module (8) that is connected between resistance value circuit (10) and the D/A converting circuit (6).

3, telecommunication line fault locator according to claim 2 is characterized in that: described short-circuit signal processing module (8) comprises negative-feedback circuit that is made of operational amplifier (IC1) and peripheral circuit thereof and the wave filter (11) that is connected its input end and output terminal.

4, telecommunication line fault locator according to claim 1 is characterized in that: the described range-measuring circuit that opens circuit (5) comprises the chopping signal processing module (9) that is connected between electric capacity value circuit and the D/A converting circuit (6).

5, telecommunication line fault locator according to claim 4, it is characterized in that: described chopping signal processing module (9) comprises the negative-feedback circuit by an operational amplifier (IC2) and one 555 timers (IC3) and peripheral circuit formation thereof, 555 timers (IC3) and peripheral circuit thereof constitute multi-harmonic-oscillations, and its 5th pin connects the output terminal of operational amplifier (IC2) by resistance (R3).