JPH0427229A - Transmitter - Google Patents

Abstract

PURPOSE:To detect a slip with a transmitter itself by constituting the transmitter so that a test pattern checking means generates periodically a data error, when an inputted test pattern is shifted from a test pattern generated by itself. CONSTITUTION:For instance, a slip is generated in the clock of a transmission line 3-1, and when it is selected by a selector 10, a PLO 11 generates a clock synchronized therewith. A test pattern generating means 12 generates a test pattern synchronized with the clock of the PLO 11, and it is written in a buffer memory 13. On the other hand, a PLO 21 generates a clock synchronized with a clock from a transmission line 1-1 selected by a selector 20, it is sent to a test pattern checking means 14, and also, becomes a read-out clock from a memory 13, and it is read out and inputted to the checking means 14. The means 14 generates the same one as the test pattern generated from the means 12, and when the inputted test pattern is shifted from that which is generated by itself, a data error is generated periodically, and the slip can be detected.

Description

[Detailed Description of the Invention] [Summary] The master clock communicates with a plurality of transmission devices that operate in synchronization with the same master clock using clocks extracted from respective transmission paths between the plurality of transmission devices. This selector selects the clock extracted from each transmission path, with the purpose of detecting a slip in a transmission device that operates in synchronization with the transmission path, even if no alarm is generated, by the transmission device itself. A phase-locked oscillator (hereinafter referred to as PLO) that operates in accordance with the clock selected by the selector, a test pattern generation means driven by the output clock of the PLO, and a test pattern generation means generated by the test pattern generation means. A buffer memory in which the test pattern is written using the output clock of the PLO and read out using the extracted clock from one of the transmission lines, and a test pattern read from the buffer memory is input and checked, driven by the extracted clock. The present invention has a configuration in which a slip detection device is added, which has a test pattern check means for checking, and a switching means for switching the selection of the selector.

[Industrial Application Field] The present invention relates to a plurality of transmission devices that operate in synchronization with the same master clock, and a master clock that communicates between the plurality of transmission devices using clocks extracted from respective transmission paths. This invention relates to an improvement in a transmission device that operates in synchronization with the .

[Conventional technology]

FIG. 4 is a block diagram of a conventional transmission system.

In FIG. 4, time division multiplexers (hereinafter referred to as TDMs) l, 2, 3, and 4° operate with a clock from a master clock generator 5, and TDM4' is TDMl, 2.3°.
are connected to the transmission line 1-1.2-1゜3-1, and the clock extraction section 1-2゜2-2.
．． 2-1. A clock is extracted from 3-1, and data is received using this extracted clock.

In this case, it has a selector 20 and a PLO 21, and the selector 20 selects a clock extraction section in which no alarm is detected, and when an alarm is detected in the selected clock extraction section, it selects a clock extraction section in which no alarm is detected. Switch to the clock extraction section. However, the alarm referred to here is a circuit alarm such as RFC, and since a clock slip is not detected, it does not become a factor for switching the selector.

[Problem to be solved by the invention]

However, in the conventional TDM4', even if a slip occurs in the clock of a certain transmission line due to a transmission line failure, the slip will not occur in TDM4' unless this slip causes a failure in other operations and an alarm is issued. TD is used to detect slip when it cannot be detected and does not issue an alarm.
There is a problem that a slip can only be detected by performing a data communication test between M4' and, for example, TDM1.

The present invention enables the transmission device (
TDM) aims to provide a transmission device that can detect slips only by itself.

[Means to solve the problem]

FIG. 1 is a block diagram of the principle of the present invention.

As shown in FIG. 1, each transmission between a plurality of transmission devices 1, 2, 3, . Road 1-
1.2-1.3-1. In the transmission device 4 that operates in synchronization with the master clock and communicates using extracted clocks from the respective transmission lines 1-1. 2-1. 3-1.・・・
a selector 10 that selects a clock extracted from the selector 10, a PLOII that operates in accordance with the clock selected by the selector 10, a test pattern generation means 12 driven by the output clock of the PLOII, and the test pattern generation means. A buffer memory 13 in which the test pattern generated from 12 is written using the output clock of the PLO II and read out using the extracted clock from any of the transmission lines; A slip detection device 30 having a test pattern checking means 14 driven by an extraction clock and a switching means 6 for switching the selection of the selector 10.
The configuration includes the following.

[For production]

In the slip detection device 30 of the present invention, for example, the transmission line 3-
Suppose that a slip occurs in the clock of selector 10.
If the clock of transmission line 3-1 is selected in , PL
OII generates a clock synchronized with this clock.

Therefore, from the test pattern generating means 12, this PLO
A test pattern synchronized with the clock of PLOll is generated, and the generated test pattern is written into the buffer memory 13 using the clock of PLOll.

On the other hand, the PLO 21 generates a clock synchronized with the clock selected by the selector 20 and extracted from the transmission line 1-1, for example, and the output clock of the PLO 21 is supplied to the test pattern checking means 14 and , becomes the read clock from the buffer memory 13,
The written test pattern is read from the buffer memory IJ13 and input to the test pattern checking means 14.

The test pattern check means 14 generates the same test pattern as the test pattern synchronized with the output clock of the PLO 21 generated by the test pattern generation means 12, and the input test pattern deviates from the test pattern generated by itself. Since data errors occur periodically, slips can be detected using this.

In addition, the transmission path 1-1 at the selector IO by the switching means 6
．． By switching the selection of clocks extracted from 2-1.3-1, it is possible to detect slips in clocks extracted from other transmission paths.

That is, by adding this slip detection device 30 to the transmission device 4, the transmission device itself can detect a slip even if no alarm is generated.

〔Example〕

FIG. 2 is a block diagram of a time division multiplexing device mainly including a slip detection device according to an embodiment of the present invention, and FIG. 3 is a diagram showing the status of read and write clocks and data of the buffer memory in FIG. 2. .

TDMl operating in synchronization with the same master clock; 2.
3 and 4 are connected through transmission lines 1-1, 2-1 and 3-1, and in TDM4, the clock extraction unit 1-
2. 2-2. In step 3-2, the clock is extracted, and the extracted clock of, for example, 8 KHz is input to the selector 20 and selected by the selection signal, and the PLO 21 generates a clock synchronized with the selected clock.

In this case, when the TDM 4 communicates with the TDMI and 2.3, the selector 20 uses the clock extraction units 1-1.2-1.3-1, respectively, as explained in the conventional example of FIG.
The PLO 21 is synchronized with the selected clock, and data is received using the generated clock.

One-way lock extraction unit 1-1.2-1. The clock extracted in step 3-1 is input to the selector 10, selected and
PLOII is synchronized with the input clock, is divided by the m frequency divider 15, becomes a 4 MHz clock, for example, and is input to the test pattern generation circuit 12,
A test pattern synchronized with this clock is generated and serves as a write clock to the buffer memory 13, and the test pattern is written into the buffer memory 13.

The clock generated by the PLO 21 is frequency-divided by the m frequency divider 19 to become a 4 MHz clock, which is manually input to the test pattern check circuit 14.

Here, write data to the buffer memory 13.

The states of the write clock, read data, and read clock are shown in FIG. 3, where the write data shown in (C) is written using the write clock shown in (D), and (
The data is read out using the read clock shown in B), and the read data is as shown in (A).

In this case, if a slip occurs in the write clock, (D
) continues to move to the right or left, and the write data also moves accordingly.

Therefore, in the test pattern check circuit 14, when the input test pattern deviates from the test pattern generated by itself, a data error is periodically generated and written in the register 16.

Since the microcomputer regularly monitors the contents of the register 16 during the day, it is possible to detect the occurrence of a slip.

The microcomputer 18 periodically selects the clock extracted by the clock extractor 3-2 via the register 17, for example, by the clock extractor 1-2.
The second selection of the clock extracted by the clock extraction section 2-
By sending a selection signal such as the selection of the clock extracted in step 2, the selection in the selector 10 is switched, and the transmission line 3-1
It is also possible to automatically detect the slip at 1-1.2-1.

Of course, the selection on the selector 10 may be switched manually.

In this way, by adding the slip detection device 30 to the TDM 4, the TDM 4 itself can detect a slip even without the occurrence of an alarm.

Although the above description has been made in the case of TDM, this is not limited to TDM and can of course be applied to any transmission device that transmits data.

(Effects of the Invention) As explained in detail above, according to the present invention, the transmission device (T
DM) It has the effect of being able to detect a slip by itself without generating an alarm.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is a block diagram of a time division multiplexing device mainly including a slip detection device according to an embodiment of the present invention, and FIG. 3 is a block diagram of the buffer memory read in FIG. FIG. 4, which shows the state of write clocks and data, is a block diagram of a conventional transmission system. In the figure, 1.2 and 3.4 are transmission equipment 1 time division multiplexing device, 1-1
．． 2-1.3-1 is a transmission line, 1-2.2-2.3-2 is a clock extractor, 4' is a time division multiplexer, 5 is a master clock generator, 6 is a switching means, 10. 20 is a selector, 11.21 is a phase synchronized oscillator, 12 is a test pattern generation means, a test pattern generation circuit, 13 is a buffer memory, 14 is a test pattern check means, a test pattern check circuit, 15.19 is an m frequency divider, 16 and 17 are registers, 18 is a microcomputer, and 30 is a slip detection device. (A) Lee F stage (B) Masudoku skin relief 3 diagram Conventional fda 1 11th system professional...F diagram 4 diagram

Claims (1)

[Claims] A plurality of transmission devices (1, 2, 3, etc.) that operate in synchronization with the same master clock, and a plurality of transmission devices (1, 2, . . . ) that operate in synchronization with the master clock. , 3,...) in a transmission device (4) that extracts clocks from each transmission path (1-1, 2-1, 3-1, . . . ) between the respective transmission paths (1-1, 3-1, . . . 1, 2-1, 3-1,...), and a phase synchronized oscillator (11) that operates in accordance with the clock selected by the selector (10). , a test pattern generating means (12) driven by the output clock of the phase synchronized oscillator (11), and a test pattern generating means (12) driven by the output clock of the phase synchronized oscillator (11).
2) The test pattern generated by the phase synchronized oscillator (
The buffer memory (13) is written using the output clock of 11) and read using the extracted clock from any of the above transmission lines.
), test pattern checking means (14) driven by the extraction clock, which inputs and checks the test pattern read from the buffer memory (13), and switching means (6) for switching the selection of the selector (10).
A transmission device characterized in that a slip detection device (30) is added.