JPH0595344A - Fault detection system - Google Patents

Abstract

PURPOSE:To easily detect a fault location by providing a generating circuit for a test signal, a loopback switch for each system and a fault detection control circuit so as to loop back a standby side automatically depending on the function when an active side is in use. CONSTITUTION:The system is provided with a fault detection control circuit 1, a signal changeover switch 2, a signal generating circuit 3, loopback switches 6, 8, 10, a signal reception circuit 11 and a fault location detection circuit 16. The fault detection control circuit 1, for example, outputs a loopback switching control signal (h) for discriminating a fault location. The signal reception circuit 11 receives a test signal (b) without an error for a prescribed time to discriminate it that the transmission interface circuit 4 and the reception interface circuit 12 are normal. Then the fault detection control circuit 1 stops the loopback switching signal (h) and when a signal (i) is outputted, since the signal (b) cannot be received without error, a fault detection signal (k) is outputted to the fault location detection circuit 16. A transmission code processing circuit 5 or a reception code processing circuit 13 is discriminated to be a circuit fault.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a fault detection system,
In particular, it relates to a failure detection method capable of identifying a failure point in a digital wireless communication system.

[0002]

2. Description of the Related Art As shown in FIG. 2, a digital wireless communication system subject to fault detection has a transmission interface circuit 4, a transmission code processing circuit 5, a modulation circuit 7, and a transmission circuit as a transmission side on each of a working side and a protection side. 9 and is switched by the changeover switch 18. As the receiving side, each of the working side and the spare side has a reception interface circuit 12, a reception code processing circuit 13, a demodulation circuit 14, and a transmission circuit 15, which are switched by a changeover switch 17. Here, in the conventional fault detection method, each of the transmission interface circuit 4, the transmission code processing circuit 5, the modulation circuit 7, the transmission circuit 9, the reception circuit 15, the demodulation circuit 14, the reception code processing circuit 13, and the reception interface circuit 12 Fault information signals m, n, p, q, r, caused by the presence / absence of pulses such as input, output, and signal interruption for each circuit
s, t, u were output, and the faulty part was judged from the output state. For example, when the failure information signal r is output from the reception interface circuit 12, since the circuit quality cannot be confirmed, the failure location is the reception interface circuit 12 that has output the failure information signal or the reception signal processing circuit of the preceding circuit. It is conceivable that the reception code processing circuit 13 that outputs an apparently erroneous signal in spite of the internal failure in 13 and does not output the failure information signal S may be in failure. Such a method of separating the two parts uses a failure detection method in which a failure part is determined by replacing the reception code processing circuit 13 of the standby circuit which operates normally.

[0003]

This conventional fault detection method has a drawback that the fault location cannot be easily specified because the fault location is judged without the circuit quality being directly confirmed by the fault information signal.

[0004]

A fault detection system according to the present invention has a transmission circuit system of two systems of a working side and a protection side, and a reception circuit system of two systems of a working side and a protection side. In the fault detection method of the digital radio communication system in which each of the system and the receiving circuit system selects and operates either the working side or the protection side, a fault detection signal is sent to at least the input part on the protection side of the transmission circuit system. A fault detection signal generating circuit for switching the main signal to the fault detection signal, a loopback switch that loops back the fault detection signal from the transmission side circuit system to the reception side circuit system, and the fault detection signal A signal receiving circuit for receiving a signal, a fault detection control circuit for controlling the loopback switch, a loopback circuit quality signal of each system, and a fault location of each circuit. Enter a signal output and a failure location detecting circuit for identifying failure location.

[0005]

The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the present invention. Figure 1
2, the same reference numerals as those in the conventional example in FIG. 2 have exactly the same configuration and functional operation. That is, in the present embodiment, the fault detection control circuit 1, the signal changeover switch 2, the signal generation circuit 3, the loopback switches 6, 8 and 10, the signal reception circuit 11, and the fault location detection circuit 16 are added.

The fault location detection on the spare side during the operation on the active side will now be described. The test signal b output from the signal generation circuit 3 is selected by the signal changeover switch 2 by the failure detection control signal a output from the failure detection control circuit 1 and output as the test signal c. The transmission interface circuit 4 outputs the test signal c as a signal d to the transmission code processing circuit 5 and the loopback switch 6. The transmission code processing circuit 5 processes various additional bits e and outputs them as a multiplexed signal f to the modulation circuit 7 and the loopback switch 8. The modulation circuit 7 modulates the multiplexed signal f and outputs it as a modulation signal g to the transmission circuit 9 and the loopback switch 10. The loopback switching control signal j from the failure detection control circuit 1
Is output, the modulated signal g is selected by the loopback switch 10 and input to the demodulation circuit 14, and the reception code processing circuit 1
The test signal e is input to the signal receiving circuit 11 via the signal receiving circuit 3 and the receiving interface circuit 12. The signal receiving circuit 11 can confirm the circuit quality by judging that the test signal b can be received for a certain period of time without error, and can judge that this route is normal. For the fault location determination, for example, the fault detection control circuit 1 outputs a loopback switching control signal h. Since the signal receiving circuit 11 can receive the test signal b without any error for a certain period of time, the signal receiving circuit 11 determines that the area between the transmitting interface circuit 4 and the receiving interface circuit 12 is normal as described above. Next, the failure detection control circuit 1 stops the loopback switching signal h and outputs i. Since the signal receiving circuit 11 cannot receive the test signal b without error for a certain period of time, it outputs the failure detection signal k to the failure location detection circuit 16. The fault location detection circuit 16 determines that the transmission code processing circuit 5 or the reception code processing circuit 13 in this route has a circuit fault, and when the fault information S is output next, the fault location is the reception code processing circuit 13 It is determined that In this way, the failure point detection circuit 16 can automatically detect the failure point from the failure information signals m, n, p, r, s, and t while confirming the circuit quality of each loopback route. Although the present embodiment has described the method of automatically detecting the faulty portion on the spare side when the active side is used in the hot standby system, the reverse configuration can also have the same configuration and function to perform automatic fault detection.

[0007]

As described above, the present invention has the test signal generating circuit, the loopback switch for each circuit system, and the fault detecting control circuit in the digital radio communication system, so that the standby side can be used when the working side is used. Can be automatically looped back by function. Therefore, it is possible to confirm the circuit quality while operating the line and easily detect the device failure location in advance.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a block diagram of a conventional fault detection method.

[Explanation of symbols]

 1 Fault Detection Control Circuit 2 Signal Changeover Switch 3 Signal Generation Circuit 4 Transmission Interface Circuit 5 Transmission Code Processing Circuit 6, 8, 10 Loopback Switch 7 Modulation Circuit 9 Transmission Circuit 11 Signal Reception Circuit 12 Reception Interface Circuit 13 Reception Code Processing Circuit 14 Demodulation circuit 15 Reception circuit 16 Fault location detection circuit 17, 18 Changeover switch

Claims (1)

[Claims] 1. A transmission circuit system of two systems, a working side and a standby side, and a receiving circuit system of two systems, a working side and a standby side, each of the transmitting circuit system and the receiving circuit system being a working side. Alternatively, in a fault detection method for a digital radio communication system that operates by selecting either the spare side, a fault detection signal generating circuit for sending a fault detection signal to at least the spare side input section of the transmission circuit system, and a main signal. To the fault detection signal, a loopback switch that loops back the fault detection signal from the transmission side circuit system to the reception side circuit system, a signal receiving circuit that receives the fault detection signal, and the loop A failure detection control circuit for controlling the back switch, a circuit quality signal of each looped back system, and a detection signal of a failure point of each circuit are input to identify the failure point. A fault detection method comprising a fault location detection circuit.