JPS60154736A - Burst synchronism system for digital subscriber's line - Google Patents

Abstract

PURPOSE:To decrease as less as possible an ineffective power consumption by allowing a subscriber's device to synchronize the bit synchronism depending on a digital subscriber's circuit and allowing the digital subscriber's circuit to synchronize the burst synchronism depending on the subscriber's device. CONSTITUTION:The subscriber's device DCE synchronizes the bit synchronism depending on the digital subscriber's circuit DLC. Moreover, the digital subscriber's circuit DLC synchronizes the burst synchronism depending on the subscriber' device DCE. Since the subscriber's device DCE decides independently the time of transmission of a subscriber burst Bs, it is possible for the digital subscriber's circuit DLC to stop the transmission of a station burst Bo when the subscriber burst Bs is stopped. That is, the power consumption mainly depending on a driver DV is decreased attended with the transmission of the station burst Bo.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a two-wire time-division transmission system subscriber line, and particularly to a digital subscriber line burst synchronization system that can stop transmitting burst signals when unnecessary.

(bl Technological Background) With the progress of digital switching technology in recent years, attempts have been made to digitize subscriber line transmission systems. Figure 1 is a diagram showing an example of a subscriber transmission system that is the subject of the present invention. 2 is a diagram showing an example of the subscriber line transmission system in FIG. 1.

In FIG. 1, a terminal device DT installed in a subscriber's premises
It is accommodated in the digital subscriber circuit DLC provided in the exchange sw via a device consisting of a subscriber circuit DCE and an in-house line termination device DCE. In FIG. 2, the digital subscriber circuit DLC adds a frame signal F and a DC balance bit B to a data signal D and a control signal S transmitted from the network NW to generate a station parse }Bo, Data signals and control signals S are transmitted from the terminal device DTE to the subscriber line SL at every burst cycle Tb.
A subscriber burst Bs is generated by adding a frame signal F and a DC balance bit B to the subscriber burst Bs, and is sent to the subscriber line SL every burst cycle Tb. In order to make it possible for the station burst BO and the subscriber burst Bs to be transmitted via the two-wire subscriber line SL without colliding with each other, the transmission timing of the station burst Bo in the digital subscriber circuit DLC, Subscriber berth (BS) in the home line terminal equipment DCE
It is necessary to perform so-called burst synchronization, which adjusts the transmission timing of the data.

(C1 Prior art and problems) In the conventional digital subscriber line burst synchronization system, the home equipment SE was dependent on the exchange SW to perform burst synchronization. In other words, the digital subscriber circuit DLC was connected to the station parse.) Bo sending timing The home line termination device DCE detects the arrival time of the office burst BO by extracting the frame signal F from the office burst BO transmitted via the subscriber line SL, and determines the arrival time. The timing for sending out subscriber burst Bs from its own device was determined based on the criteria.

However, in such a digital subscriber line burst synchronization system, if the subscriber is absent, it is also possible to turn off the power to the terminal device DTE and the home line termination device DCE, and stop sending subscriber burst Bs. However, if the digital subscriber circuit DLC does not always send out the station parse) Bo, the timing of sending the subscriber burst BS cannot be determined when the power is turned on to the home line termination device DCE, so the digital subscriber Since the circuit DLC transmits the station-based I-Bo even when the home equipment SE is out of function, power is wasted, and the noise level imparted to adjacent subscriber lines due to crosstalk also increases. There was a drawback.

(d) Object of the Invention An object of the present invention is to eliminate the drawbacks of the conventional digital subscriber line burst synchronization system as described above, and to minimize the reactive power consumption in the digital subscriber circuit and the noise level imparted to adjacent subscriber lines. The goal is to realize means that can reduce the amount of damage.

(el) Structure of the Invention The purpose of this invention is to implement a two-wire time-division transmission system in which a digital subscriber circuit connected to a two-wire subscriber line and an in-home device transmit burst signals to each other in a time-division manner at a predetermined period. In the subscriber line, the subscriber equipment has means for independently determining when to send out the burst signal from the subscriber circuit, and a means for extracting a clock signal generated within the subscriber unit from the burst signal transmitted from the digital subscriber circuit. means for synchronizing with a clock signal transmitted from the home device, and the digital subscriber circuit includes a means for detecting a burst signal transmitted from the home device, and a means for transmitting a burst signal from the own device based on the arrival time of the burst signal detected by the means. This is achieved by providing a means for determining when to do so.

That is, in the present invention, the bit synchronization is carried out by the in-home device being subordinated to the digital subscriber circuit, while the burst synchronization is being carried out by the digital subscriber circuit being subordinated to the in-home device. Therefore, even if the digital subscriber circuit stops transmitting bursts when the domestic device stops transmitting bursts, there is no problem for the domestic device to resume transmitting bursts.

(f) Examples of the invention An embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a diagram showing a digital subscriber line burst synchronization method according to an embodiment of the present invention, and FIG. 4 is a diagram showing an example of the subscriber line transmission method in FIG. 3. Note that the same reference numerals refer to the same objects throughout the plan. In FIG. 3, the home line termination device DCE is a station (perspective) B arriving from the subscriber line SL.

bit synchronization, which extracts the clock signal on the exchange SW side from the station burst BO received by the reception circuit RC and synchronizes the clock signal supplied from the clock generation circuit CG in the residential line termination device DCE. circuit BS, frame synchronization circuits F and S that detect frame signal F from station burst BO, separate data signal and control signal S, and transmit them to terminal device DTE (not shown); A transmitting circuit SD generates a subscriber burst BS by adding a frame signal F and a DC signal line B to a data signal and a control signal S, and sends the subscriber burst BS to a subscriber line SL via a driver DV; The digital subscriber circuit DLC includes a receiving circuit RC for receiving the subscriber no.BS arriving from the subscriber line SL. The receiving circuit RC extracts the clock signal of the subscriber's device SE side from the BS (subscriber parse) received by the receiving circuit RC, and sends it to the digital subscriber circuit DLC.
A bit-node synchronization circuit BS synchronizes clock signals supplied from a clock generation circuit CG provided therein, and a receiver circuit RC temporarily stores the subscriber burst Bs received.
Extracted by station clock signal OC and sent to frame synchronization circuit F
A frame signal F is detected from the subscriber burst Bs transmitted from the Elastane Inkstore ES and the Elastane Inkstore BS, and a data signal and a control signal S are separated, and the frame is transmitted to a network NW (not shown). A frame signal F and a DC balance signal node B are added to the data signal and control signal S transmitted from the synchronous circuit FS and the network NW to create a station berth I-BO.
The transmission circuit SD generates the frame signal F and sends it to the subscriber line SL via the driver D■, and the reception circuit RC receives the frame signal F from the subscriber burst) Bs, thereby determining the arrival time of the subscriber burst Bs. The subscriber monitoring circuit SP detects and transmits it to the burst timing circuit BT, and based on the arrival timing of the subscriber purse (Bs) transmitted from the subscriber monitoring circuit SP, the sending timing of the station purse (Bo) to the subscriber line SL is determined. It is equipped with a burst timing circuit BT for determining the burst timing. In FIGS. 3 and 4, the bit synchronization circuit BS in the residential line termination device DCE extracts a clock signal from the station burst BO received by the reception circuit RC, and extracts the clock signal from the station burst BO received by the reception circuit RC, and extracts the clock signal from the clock generation circuit CG. are synchronized and supplied to the frame synchronization circuit FS and the burst timing circuit BT. Nost timing circuit BT
independently determines the sending timing of the subscriber's purse (Bs) every burst period Tb in synchronization with the clock signal supplied from the bit synchronization circuit BS, and transmits the transmission circuit SD and the reception circuit R.
Communicate to C.

Based on the sending timing, the sending circuit SD sends the generated subscriber burst Bs to the subscriber line SL via the driver DV, and the receiving circuit RC determines the receiving timing of the station burst Bo arriving from the subscriber line SL. do.

The subscriber burst B s arrives at the digital subscriber circuit DLC via the subscriber line SL. The focus synchronization circuit BS in the digital subscriber circuit DLC extracts a clock signal from the subscriber hearth (Bs) received by the receiving circuit RC, synchronizes the clock signal supplied from the clock generation circuit CG, and converts the clock signal to the subscriber monitoring circuit SP. and communicate to Elastic Store ES. The subscriber monitoring circuit SP receives a frame signal F from the subscriber burst Bs received by the receiving circuit RC.
By extracting the subscriber burst Bs, the arrival time of the subscriber burst Bs is detected and transmitted to the burst timing circuit BT. The burst timing circuit BT controls the station burst B at every burst period Tb in synchronization with the station clock signal oc from the arrival time of the subscriber's purse (Bs) transmitted from the subscriber monitoring circuit SP.
The sending timing of O is determined and transmitted to the transmitting circuit SD. The transmitting circuit SD transmits the generated office burst Bo to the subscriber line SL via the driver DV based on the transmitting timing transmitted from the burst timing circuit BT. In such a state, when the subscriber is absent and the power to the residential line terminating device DCE is cut off, each circuit of the residential line terminating device DCE stops functioning, and the subscriber burst B to the subscriber line SL is turned off.
Sending of s is also stopped. In the digital subscriber circuit DLC, the subscriber monitoring circuit SP detects that transmission of the subscriber burst BS has stopped since the frame signal F can no longer be extracted, and transmits the arrival timing of the subscriber burst Bs to the burst timing circuit BT. Stop.

As a result, the burst timing circuit BT is connected to the transmitter circuit SD.
The transmission circuit SD stops transmitting the transmission timing of the station burst Bo to the subscriber line SL via the driver DV. When the subscriber takes a seat in this state and turns on the power to the home line terminating device DCE, the focus synchronization circuit BS in the home line terminating device DcE generates a clock because the station burst Bo has not yet arrived from the subscriber line SL. A clock signal supplied from circuit CG is transmitted to its side frame synchronization circuit FS and burst timing circuit BT. Burst timing times 11BT
Based on the clock signal transmitted from the bit synchronization circuit BS, the subscriber burst signal Bs is sent to the transmission circuit SD in the above-mentioned process.
is sent to subscriber line SL. When the subscriber purse (BS) arrives from the subscriber line SL, the digital subscriber circuit DL
C starts transmitting the station burst Bo to the subscriber line SL in the process described above.

As is clear from the above explanation, according to the present embodiment, since the home line termination equipment WDcE independently determines the transmission timing of the subscriber burst BS, the digital subscriber circuit DLC is configured to transmit the subscriber burst BS when the subscriber burst BS stops. It is now possible to stop the transmission of the station burst Bo, and the power consumption centered on the driver DV can be reduced as the station burst Bo is transmitted. Also, while the station burst Bo is stopped, the subscriber line SL
The noise level due to crosstalk to other subscriber lines (not shown) can also be reduced.

It should be noted that FIGS. 3 and 4 are only one embodiment of the present invention, and the configurations of, for example, the residential line termination device DCE and the digital subscriber circuit DLC are not limited to those shown in the figures. Many other modifications may be considered, but the effects of the present invention will not change in any case. Also, the configurations of the subscriber burst Bs and the station purse (Bo) are not limited to those shown in the drawings; Although many variations are considered,
In either case, the effects of the present invention remain the same. Furthermore, it goes without saying that the subscriber transmission system to which the present invention is applied is not limited to that shown in the drawings.

fg) Effects of the Invention According to the present invention, in the two-wire time-division transmission system subscriber line, the digital subscriber circuit can stop transmitting the station burst when the subscriber burst stops, It is possible to reduce reactive power consumption in digital subscriber circuits and the noise level imparted to adjacent subscriber lines.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an example of a subscriber transmission system to which the present invention is applied, Fig. 2 is a diagram showing an example of the subscriber line transmission system in Fig. 1, and Fig. 3 is a diagram according to an embodiment of the present invention. Figure 4 shows the digital subscriber line burst synchronization method.
It is a figure which shows an example of the subscriber line transmission system in a figure. In the figure, B is a DC balance bit, Bo is a station burst, Bs is a subscriber burst, BS is a pinto synchronization circuit, and B
T is burst timing circuit, CG is clock generation circuit, D is data signal, DCE is home line termination equipment, DLC
is a digital subscriber circuit, DTE is a terminal device, DV is a driver, BS is an elastic store, F is a frame signal, FS is a frame synchronization circuit, oc is a station clock signal,
RC is a receiving circuit, S is a control signal, SD is a transmitting circuit, SE
is the home equipment, SL is the subscriber line, SP is the subscriber monitoring circuit,
SW indicates a switch, and T'b indicates a burst cycle. Number! Close-up? Shumine 3 Shoryo 4 rooms

Claims (1)

[Claims] In a two-wire time-division transmission system subscriber line in which a digital subscriber circuit and a home device connected by a two-wire subscriber line transmit burst signals to each other in a time-division manner at a predetermined period, the home device means for independently determining when to send out the burst signal from the own device; and means for synchronizing a clock signal generated within the own device with a clock signal extracted from the burst signal transmitted from the digital subscriber circuit. and the digital subscriber circuit is provided with means for detecting a burst signal transmitted from the home device and means for determining when to send out the burst signal from the own device based on the arrival time of the burst signal detected by the means. A digital subscriber line burst synchronization method characterized by: