JPH03212035A - Multiplex transmission system via remote equipment - Google Patents

Abstract

PURPOSE:To keep an error of a transmission phase of a subscriber within an allocated channel and to prevent effect on other channels even when the error takes place in the transmission phase of the subscriber by using a remote equipment to give a multiplex phase of each subscriber. CONSTITUTION:A digital signal from each subscriber is subjected to bit multiplex in the order of subscribers 31-34 by a multiplex circuit 11 in a remote equipment 1 in a transmission system from the subscribers 31-34 to a master set 2 via the remote equipment 1 and the result is sent to the master set 2 through a transmission line 13. The master set 2 uses a demultiplex circuit 21 to expand the bit multiplex and a detection circuit 24 monitors the expanded output and uses an outgoing transmission line to inform reception disabled state to a subscriber sending a channel from which a normal transmission frame is received. The subscriber receiving the notice varies a phase of a transmission clock. Thus, even when the setting of the transmission phase of the subscriber is incomplete, no effect is given to other channels.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multiplex transmission system in a transmission system in which a plurality of transmitting devices are multiplexed by a remote device and then accommodated.

[Conventional technology]

As a system for accommodating subscribers via remote equipment, there is an optical transmission system shown in FIG. Main device 2 is subscriber 31.32
．． Downlink signals to ... (signal blocks A, B, C
) is multiplexed and supplied to the remote device 1.

An optical splitter 15 in remote unit l distributes this signal to each subscriber. The subscriber extracts only his own channel from the multiplexed signal and supplies it to the receiving end within the subscriber. on the other hand,
Regarding transmission, each subscriber receives bursty signals (signal blocks a, b,
c) - This signal is sent to the optical coupler 1 in the remote device 1.
4 and is supplied to the main device 2 in a multiplexed form.

To implement this transmission method, each subscriber must
It is necessary to control the transmission phase so that time division multiplexing is performed correctly on the upstream transmission path 13 from the main device 2 to the main device 2.

This monitors the multiplexed transmission signal received by the main device 2 and notifies subscribers who are not multiplexed at the assigned position via the downstream transmission path to control the transmission phase.
This is achieved through control.

[Problems to be Solved by the Invention] The above-mentioned conventional technology has the advantage of being able to process digital signals as they are as light, but if a certain subscriber's transmission phase is not set correctly or malfunctions,
There is a problem that it affects other channels. Additionally, the subscriber's transmission rate must be multiplexed by the remote device and transmitted at the transmission rate, requiring circuits operating at commercial speeds.

An object of the present invention is to provide a multiplex transmission method via remote equipment that is suitable for handling digital signals as optical signals and that does not affect other channels even if the transmission phase setting of one subscriber is incomplete. It's about doing.

[Means to solve the problem]

The present invention is a multiplex transmission method for a system in which N transmitting devices are accommodated in a main device via a remote device. , the main device notifies the transmitting device that is transmitting the channel signal that is not normally received among the N channel signals that it cannot receive the signal, and the transmitting device that has received the notification changes its transmission phase. It is characterized by

According to the present invention, a transmitting device attaches a channel number that identifies itself to a transmitted digital signal and transmits it, and the main device selects a transmitting device whose channel number is not detected among N channels from a remote device. , is the transmitting device that is transmitting the channel signal that was not normally received, and it is preferable to notify this transmitting device that reception is not possible.

〔Example〕

FIG. 1 shows a transmission system implementing the invention. To simplify the explanation, only the transmission system from the subscriber 3132, 33, 34 to the main device 2 via the remote device 1 is shown.

In this transmission system, the digital signal from each subscriber is transmitted to subscriber 31 in multiplex circuit 11 in remote unit I.
．． The signals are bit-multiplexed in the order of 32, 33, and 34 and sent to the main device 2 via the transmission line 13.

FIG. 2 shows the structure of the digital signal transmitted from each subscriber. A frame synchronization signal F and a channel ID identifying each subscriber are given.

In the main device 2, the demultiplexing circuit 21 expands bit multiplexing, and the detection circuit 24 monitors the expanded output and detects a channel from which a normal transmission frame is not received, for example, a channel whose channel ID is not detected. A control unit (not shown) notifies the subscriber transmitting this channel, using the downlink transmission path, that reception is not possible and controls the phase of the transmission clock. The notification method using this downlink transmission path is the same as the above-mentioned conventional example.

Multiplexing in the remote device 1 and separation control in the main device 2 will be explained using the received signal in the remote device 1 and the operation timing of multiplex control shown in FIG. This figure shows a case where the transmission phase of each subscriber is set correctly. Transmitted digital signals S31. from subscribers 31, 32, 33, 34. S32°S33. Multiplexed pulse Pi generated by counter 12 corresponding to S34
, P2. P3. P4 is supplied to multiplex circuit 11 and subscriber 3
Bit signal (al, a2) from 1.32.33.34
, (bl, b2), (cl.

c2), (di, d2) are multiplexed at 4 times the transmission speed,
A multiplexed signal S13 is output.

In the main device 2, it is necessary to supply a prescribed signal, for example, a signal from the subscriber 3L 32.33.34, to the expansion outputs 41, 42, 43, 44, and this control is performed as follows. conduct. Now, assume that the channel ID of the subscriber 34 is detected in the expanded output 41. In the remote device 1, the bits are multiplexed in the order of subscribers 31, 32, 33, and 34, so the expanded output 42, 43, and 44 are
Channel IDs of 32 and 33 are detected in sequence. Based on this detection result, the control circuit 23 controls the counting operation of the counter 22, and outputs the expanded outputs 41, 42, 43, 44 to the subscriber 3.
1.32.33.34 digital signals are supplied.

The above is an explanation of the case where the transmission phase of each subscriber is set correctly. Next, the case where the transmission phase of each subscriber is not set correctly will be explained using FIGS. 4 and 5. In Figure 4,
The transmission clock 03'' of the subscriber 31 and the transmitted digital signal S31' at that time are shown, and this digital signal 831' is converted into the multiplexed signal S by the multiplexed pulse P1.
The signals are multiplexed as shown in the shaded area No. 13. In the case of the figure, the digital signal S31' changes in the multiplexed channels shown in the shaded area, and even if this multiplexed signal is separated in the main device 2, it cannot be correctly restored. The detection circuit 24 that has detected this notifies the subscriber 31 of the change in the transmission phase using a downstream communication means.

The subscriber 31 who received the notification changes the phase of the transmitting clock to 18.
Shift by 0° and change to the illustrated transmission clock 03''.

The transmission digital signal 331'' generated by the changed transmission clock C, -3'' at the phase shown in the figure is sent to the multiplex circuit 11.
supply to. This makes it possible to eliminate changes in data within the multiplex channel shown by the shaded area. in this case,
As in the case shown in FIG. 3, the main device 2 can correctly separate the received signals.

FIG. 5 shows an example of a transmission clock phase control circuit within a subscriber, and transmission data is latched by a flip-flop 52 and sent out as a transmission digital signal. The output clock is supplied to the flip-flop 52 via the exclusive OR gate 51.

By controlling one input of the exclusive OR gate 51 by the controller 53 within the subscriber, the phase of the transmission clock is shifted by 180°, that is, the transmission clock C in FIG.
Control is realized to change the transmission clock from C3' to C3''.

〔Effect of the invention〕

In accordance with the present invention, each subscriber's multiplexing phase is provided at the remote unit, so that if an error occurs in the transmit phase of one subscriber, the error remains within the assigned channel and is not transmitted to other channels. No impact. Furthermore, the transmission rate of each subscriber may be the same as the signal rate of the transmitted digital signal and does not require high speed operation. Furthermore, since the processing within the remote device is limited to bit multiplexing, by applying an optical switch, it is possible to multiplex the transmission signals without converting them into electricity.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a diagram showing transmission frames from each subscriber, Figs. 3 and 4 are diagrams showing operation timing, and Fig. 5 is a diagram showing transmission frames from each subscriber. FIG. 6 is a diagram showing a conventional example. ■...Remote device 2...Main device 31, 32.33.34...Subscriber 11...Multiple circuit 12, 22...Counter 13...Transmission 14. . . . . 15. . . . 21. . Circuit, control circuit, detection circuit, gate, flip-flop, control section

Claims (2)

[Claims] (1) A multiplex transmission method in a system in which N transmitting devices are accommodated in the main device via remote devices, in which the remote device bit-multiplexes the transmitted digital signals from each transmitting device and transmits them to the main device, The main device notifies the transmitting device that is transmitting the channel signal that was not normally received among the N channel signals that reception is not possible;
A multiplex transmission system via a remote device, characterized in that the transmitting device that has received the notification changes its transmission phase. (2) The transmitting device attaches a channel number that identifies itself to the transmitted digital signal and transmits it, and the main device normally sends the transmitting device whose channel number is not detected among the N channels from the remote device. 2. The multiplex transmission system via a remote device according to claim 1, wherein the transmitting device is a transmitting device that is transmitting a channel signal that is not received, and the transmitting device is notified that reception is not possible.