JPS61148943A - Pulse code modulation two-way communication equipment - Google Patents

Abstract

PURPOSE:To locate a faulty repeater with simple constitution by allowing an intermediate repeater to transmits reversely a signal modulated by a frequency specific to the intermediate repeater and allowing a terminal station repeater to identify the signal. CONSTITUTION:When a main signal from the terminal station repeater 1 is intermitted in the intermediate repeater 2, a main signal input interruption detecting circuit 23 detects it to control a signal switch 25 and an output of a modulation circuit 31 is inputted to a transmitter 27. An electric signal indentified and recovered from the main signal from a terminal station repeater 1, by a receiver 22 is branched and inputted to the circuit 31 and branch signal is subjected to mark rate modulation by using a low frequency signal specific to the intermediate repeater outputted from an oscillator 29. Thus, the output of the oscillator 27 is a signal formed by applying mark rate modulation to the main signal from the terminal station repeater 1' by low frequency signal inherent to the intermediate repeater. The repeater 1' uses an LPF to separate a low frequency component from the received signal, identifies the separated low frequency signal as to which intermediate repeater the signal comes from and the repeater having a fault is decided.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pulse code modulation bidirectional communication device in which end station relay devices are connected via a bidirectional signal line and a plurality of intermediate relay devices. In particular, the present invention relates to a configuration for automatically locating the location of a fault in a line or relay device in such a device.

〔overview〕

The present invention provides a pulse code modulation bidirectional communication device in which end station relay devices are connected via a bidirectional signal line and a plurality of intermediate relay devices, wherein the intermediate relay device receives a unidirectional signal input from the line. When a signal line is interrupted, a signal modulated at a frequency unique to that intermediate relay device is sent back in the other direction, and the end station relay device identifies this unique frequency to locate the fault location in the signal line. It is something to do.

[Conventional technology]

In the conventional monitoring method of pulse code modulation two-way communication equipment, ■ Providing an intervening line for monitoring, ■ Receiving the signal (main signal) from the terminal relay device at the intermediate relay device.
The fault location signal from the end station repeater is looped back at each intermediate repeater to locate the faulty repeater.

[Problem that the invention seeks to solve]

However, the method (2) has the disadvantage that it requires an additional intervening line in addition to the signal line for transmitting the main signal. Furthermore, the method (2) requires frame synchronization between the main signal and the failure information, which has the disadvantage of increasing the circuit scale of the intermediate relay device. Furthermore, the method (2) requires the terminal relay device to have a function to send out a special pattern signal for the fault position signal, and the intermediate relay device has the disadvantage that it requires a function to detect and identify this signal. Furthermore, there is a drawback that it is not possible to locate a failed relay device unless bidirectional main signal transmission is stopped.

The present invention solves the above drawbacks and provides pulse code modulation bidirectional communication that does not require additional intervening lines and can automatically locate a faulty relay device using a simple device. The purpose is to provide equipment.

[Means for solving problems]

The pulse code modulation bidirectional communication device of the present invention comprises a pair of bidirectional signal lines that transmit pulse code modulated signals in each direction, and terminals connected to both ends of this line that transmit and receive pulse code modulated signals. In a pulse code modulation two-way communication device comprising a station relay device and a plurality of intermediate relay devices that are inserted into this line and that identify and reproduce signals on this line for each direction and output the same, the intermediate relay device The method includes a means for detecting the interruption of the input signal from the line, a means for branching the input signal of the line in the direction opposite to the direction in which the input signal was interrupted, and a means for branching the branched signal at a characteristic low frequency. The terminal relay device includes a means for performing mark rate modulation with a modulated signal, and a means for transmitting the output of the means for performing mark rate modulation to a line in the opposite direction to the direction in which the input signal is interrupted. The present invention is characterized by comprising means for identifying the frequency of the modulated signal from the signal.

[Effect]

In the pulse code modulation two-way communication device of the present invention, when the intermediate relay device detects that the signal from the end station relay device is interrupted, each intermediate relay device Outputs a signal that has been subjected to mark rate modulation at a frequency specific to . The terminal relay device receives this signal and identifies its modulation frequency, thereby locating the relay device in which the fault has occurred.

〔Example〕

FIG. 1 is a block diagram of a pulse code modulation bidirectional communication device according to an embodiment of the present invention.

The terminal relay device 1.1' is connected via a bidirectional signal line and a plurality of intermediate relay devices 2.2'.

The intermediate relay device 2.2' includes a main signal input disconnection detection circuit 23 that detects when the input of the main signal from the signal line is interrupted.
．． 24, a branch circuit that branches the main signal in the opposite direction to the direction of the interrupted main signal, an oscillation circuit 29 that generates a low frequency signal at a unique frequency, and a branch circuit that branches the signal branched by the branch circuit into the oscillation circuit 29. A modulation circuit 30 that performs mark rate modulation on its output.
31.

Details of the intermediate relay device 2.2' will be explained later.

The terminal relay devices l, 1' include detection circuits 1) for receiving pulse code modulated main signals. 1)' is provided, and this detection circuit 1). 1)' are connected to detection and identification circuits 12 and 12'. This detection/identification circuit 12, 12' detects a low frequency signal specific to each intermediate relay device and locates the relay device in which the fault has occurred.

FIG. 2 is a block diagram of the intermediate relay device 2. As shown in FIG.

The main signal from the terminal relay device 1 is input to the receiver 21 . A main signal input disconnection detection circuit 23 is connected to the receiver 21 . The main signal input disconnection detection circuit 23 controls the connection of the signal switch 25. The signal switch 25 switches and connects the input of the transmitter 27 to the output of the receiver 21 or the output of the modulation circuit 31. The output of the transmitter 27 is transmitted to the terminal relay device 1
′. The output of the receiver 21 is branched and input to a modulation circuit 30.

An oscillator 29 is connected to the modulation circuit 30.

The main signal from the terminal relay device 1' is input to the receiver 22. A main signal input disconnection detection circuit 24 is connected to the receiver 22 . The main signal input disconnection detection circuit 24 is a signal switch 26
Connect and control. The signal switch 26 switches and connects the input of the transmitter 28 to the output of the receiver 22 or the output of the modulation circuit 30. The output of the transmitter 28 is sent toward the terminal relay device 1 . The output of the receiver 22 is branched and input to the modulation circuit 31.

An oscillator 29 is connected to the modulation circuit 31 .

Since this intermediate relay device 2 is configured symmetrically with respect to the signal transmission direction, here, the case where the main signal from the terminal station relay device 1 to the terminal station relay device 1' is interrupted will be explained as an example. .

The main signal from the terminal relay device 1 is sent to the terminal relay device 1' side via the receiver 21 and the transmitter 27, and the main signal from the terminal relay device 1' is sent to the receiver 22 and the transmitter 27. 2
8 to the terminal relay device 1 side. When the main signal from the terminal relay device 1 is interrupted, the main signal input interruption detection circuit 23 detects this, controls the signal switch 25, and inputs the output of the modulation circuit 31 to the transmitter 27. The modulation circuit 31 transmits the main signal from the terminal relay device 1' to the receiver 2.
The electrical signal identified and reproduced in step 2 is branched and inputted, and this branched signal is subjected to mark rate modulation with a low frequency signal of a frequency specific to the intermediate repeater outputted by an oscillator 29. Therefore, the output of the transmitter 27 is a signal obtained by modulating the main signal from the terminal repeater 1' with a low frequency signal unique to the intermediate repeater.

The terminal relay device 1' uses a low-pass filter to separate low frequency components from the received signal, identifies the frequency of the separated low frequency signal, and identifies which intermediate relay device the signal is from. , locate the failed relay device.

〔Effect of the invention〕

As explained above, the pulse code modulation two-way communication device of the present invention can be used in a simple manner, without using additional intervening lines, without interfering with transmission in the direction opposite to the direction in which a fault has occurred, and moreover, automatically It is possible to locate a relay device in which a failure has occurred. In particular, since the equipment added to a large number of intermediate relay devices is small, the cost of the entire device can be kept low. INDUSTRIAL APPLICATION This invention has a great effect on the maintenance and operation of the relay device of a pulse code modulation two-way communication device.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a pulse code modulation bidirectional communication device according to an embodiment of the present invention. FIG. 2 is a block diagram of the intermediate relay device. 1.1'...Terminal relay device, 2.2'...Intermediate relay device, 21.22...Receiver, 23.24...Main signal input disconnection detection circuit, 25.26...・Signal switcher,
27.28... Transmitter, 29... Oscillator, 30.3
1... Modulation circuit.

Claims (1)

[Claims] (1) A pair of bidirectional signal lines that transmit pulse code modulated signals in each direction, end station relay equipment connected to both ends of this line that transmits and receives pulse code modulated signals, and In a pulse code modulation two-way communication device equipped with a plurality of intermediate relay devices that are inserted and that identify and reproduce the signals on this line in each direction and output the signals, the intermediate relay device receives an input signal from the line. means for detecting the interruption; means for branching the input signal of the line in the direction opposite to the direction in which the input signal is interrupted; and the branching means subjects the branched signal to mark rate modulation with a modulation signal of a unique low frequency. and means for transmitting the output of the means for applying mark rate modulation to a line in the opposite direction to the direction in which the input signal is interrupted, and the terminal relay device is configured to detect the frequency of the modulated signal from the received signal. A pulse code modulation two-way communication device, characterized in that it comprises identification means.