JPS62146048A - Repeater - Google Patents

Abstract

PURPOSE:To shorten the restoration time of a repeater and to prevent a relay transmission system from stopping the function for a long time, by inserting dummy data to the position of momentary break to transmit this data when the occurrence of momentary break during relay transmission is detected and shortening the time of momentary break thereby. CONSTITUTION:A receiving circuit 2 receives a signal (a) from a transmission line to reproduce data and clocks. If the reception signal (a) to be continuously received is dropped out for a certain time, the reception stop due to momentary break is detected by a signal break detecting circuit 5 to output a signal break detection signal (c). When the signal (c) is logic '1', it indicates the reception stop, and a signal selecting circuit 4 selects dummy data (f) and a dummy clock (g) supplied from a signal generating circuit 3. As the result, most of the momentary break position of the reception signal is compensated with dummy data (f) in a transmission signal (d) which a transmission circuit 6 transmits to the transmission line.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a relay device, and particularly to a relay device that serves as a repeater in data transmission or as a node stage that constitutes a loop network.

[Conventional technology]

In a data transmission line in which multiple repeaters are connected in cascade or in a loop network in which multiple nodes/stages are connected in a ring, the functions of the repeaters, nodes, and stages may be momentarily interrupted due to a momentary power outage, etc. Sometimes.

In conventional relay devices, when such a momentary interruption occurs, the signal on the transmission line is momentarily interrupted, and this signal interruption state is relayed and transmitted by a repeater or a node/stage.

[Problem that the invention seeks to solve]

For this reason, the conventional nine relay devices have a drawback in that the number of signal disconnections increases during relay transmission.

For example, literature (Re5ults of the At1a
uta Expe-riment”, the Be1l
System Technical Jour-na
l, pp, 1,857-1,879, July-
In an optical repeater having an AGC circuit and an AC-coupled amplifier circuit, as shown in Fig. 13 of August 1978), it may take a long time to recover from a momentary interruption of the received signal. A transmission line in which such original repeaters are connected in cascade has the disadvantage that once a signal disconnection occurs, the number of signal interruptions increases, and it takes a long time to restore the normal function of the transmission line.

[Means for solving problems]

The relay device of the present invention includes a receiving circuit that receives a signal from the transmission path, a signal disconnection detection circuit that detects when the signal from the transmission path has stopped, and a signal disconnection detection circuit that sends out a certain data signal when the received signal has stopped. a signal generating circuit for selecting a receiving circuit output signal and a signal generating circuit output signal based on the output signal of the signal disconnection detecting circuit; and a transmitting circuit for sending the signal of the signal selecting circuit to a transmission path. It consists of:

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

The relay device shown in FIG. 1 is an example of a digital baseband relay device.

The receiving circuit 2 is connected to a transmission line via a receiving signal terminal 1 to which a received signal a is supplied, receives a signal from the transmission line, and reproduces data and a clock. A signal disconnection detection circuit 5 connected to the receiving circuit 2 detects the termination of the received signal, generates a signal disconnection detection signal C, and controls the signal selection circuit 4. The signal selection circuit 4 is connected to the reception image NI2 and the signal generation circuit 3, and the transmission data h and transmission clock i selected by the signal selection circuit 4 are supplied to the transmission circuit 6. A transmission signal d, which is the output of the transmission circuit 6, is sent out to a transmission path via a transmission signal terminal 7.

FIG. 2 is an operation timing chart of the digital baseband repeater according to the embodiment shown in FIG.

In the time chart shown in FIG. 2, the received signal a, the received data b1, and the transmitted signal d indicate the envelope rope of the signals. In the operation example shown in FIG. 2, the received signal a, which should originally be received continuously, is missing for a certain period of time. When such reception signal a is received, as shown in reception data b, it takes time to return to a normal reception state when reception is resumed.

In the relay device of the present invention, the signal interruption detection circuit 5 detects reception stoppage due to such a momentary interruption of the received signal a, and outputs a signal interruption detection signal C. When the signal disconnection detection signal C is logic “1”, it indicates that the reception is stopped, and at this time, the signal selection circuit 4
selects dummy data f and dummy clock g supplied from the signal generation circuit 3. As a result, in the transmission signal d that the transmission circuit 6 sends out to the transmission path, most of the instantaneous interruptions in the reception signal are compensated for by the dummy data f.

〔Effect of the invention〕

The relay device of the present invention has the advantage that when a momentary interruption occurring during relay transmission is detected, dummy data is inserted and disconnected at the point of momentary interruption, thereby eliminating the need for a long-term suspension of function.

Furthermore, the relay device of the present invention is effective not only in relay transmission systems but also in optical loop networks.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the embodiment shown in FIG. l... Reception signal terminal, 2... Receiving circuit, 3... Old signal generation circuit, 4... Signal selection circuit, 5... Signal disconnection. Detection circuit, 6...Transmission circuit, 7...Transmission signal terminal, a...Reception signal, b...Reception data,
C: signal loss detection signal, d: transmission signal, e: reception clock, f: dummy data, g: dummy Clock, h...
...Transmission data, i...Transmission clock.

Claims (1)

[Claims] a receiving circuit that receives a received signal from a transmission path and outputs received data and a received clock; a signal loss detection circuit that detects that the received data has stopped and outputs a signal loss detection signal; and dummy data and a dummy signal. a signal generation circuit that generates a clock; and a signal that selects the dummy data and the dummy clock instead of the reception data and the reception clock to output transmission data and the transmission clock when the signal disconnection detection signal is supplied. A relay device comprising: a selection circuit; and a transmission circuit that sends a transmission signal to a transmission path in response to the transmission data and the transmission clock.