KR100280210B1 - Clock generation / distribution apparatus and method in ATM switching system - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clock generation / distribution apparatus and method in an Asynchronous Transfer Mode (ATM) switching system. In particular, the system clock provided to a switch block and various matching blocks can be generated and distributed within one board. And a clock generation / distribution apparatus and method in an ATM switching system.

Conventionally, since the clock generation means and the clock distribution means are connected by separate cables, there is a problem that jitter occurs in the clock input from the clock distribution means, or that the clock stability due to synchronization loss is unreliable. As a distribution board is used, component cost and manufacturing cost have been increased.

The present invention performs the clock generation and distribution function for the system clock required in the switch block and various matching blocks of the ATM switching system on a pattern within a board, and by performing the redundancy distribution function in the triplex generation unit, the corresponding system clock It is possible to prevent delays, jitter, and wander, which can provide a stable system clock.

Description

Clock generation / distribution apparatus and method in ATM switching system

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clock generation / distribution apparatus and method in an Asynchronous Transfer Mode (ATM) switching system. In particular, the system clock provided to a switch block and various matching blocks can be generated and distributed within one board. And a clock generation / distribution apparatus and method in an ATM switching system.

In general, a clock generation / distribution apparatus in an ATM switching system includes a clock generation means 10 for generating a system clock and a clock distribution means 20 for distributing a generated clock, as shown in FIG. 1. It consists of

The clock generation means 10 generates a system clock synchronized with an external synchronization reference clock provided from the outside, and provides the clock distribution means 20 with a digital processing phase locked loop (DP-PLL) synchronization method.

The clock distribution means 20 distributes the system clock provided from the clock generation means 10 to a switch block and various matching blocks through an intermodule interface.

Here, the clock generating means 10 is divided into one master board 11 and two slave boards 12 and 13 in consideration of the stability and reliability of the clock, and is configured in triple, and in the corresponding master board 11 The generated clock Clock0 is selected as the system reference clock by the clock distribution means 20, and each slave board 12 and 13 selects the clock Clock0 of the master board 11 as the internal synchronization reference clock and PLL. The clock distribution means 20 is provided in a synchronous manner.

In addition, each clock port of the clock generation means 10 and the clock distribution means 20 outputs a system clock at an ECL (Emitter Coupled Logic) differential level, and the clock distribution means 20 is a master to maintain reliability. The board 21 and the slave board 22 are dualized, and the clock Clock0 provided from the master board 11 of the clock generating means 10 is selected as the system reference clock.

The clock generation and distribution operation in the conventional ATM switching system configured as described above is performed as follows.

First, when the clocks Clock 0 to Clock 2 are provided from the master board 11 and the slave boards 12 and 13 of the clock generating means 10 to the clock distribution means 20, the corresponding clock distribution means 20 is clocked. The master clock (Clock0) provided from the master board 11 is selected as the system reference clock among the clocks provided from the generating means 10 and distributed to the switch block and various matching blocks through the inter-module interface, and each slave board 12 , The slave clocks Clock1 and Clock2 provided from 13 only receive.

In other words, in the conventional ATM switching system, the clock generation board of the clock generation means 10 composed of triplexing receives an external synchronization reference clock to generate a system clock in a DP-PLL synchronization manner and provides the clock to the clock distribution means 20. The clock distribution board of the corresponding clock distribution means 20 is configured to receive a system clock from each clock generation board, select one of them as a system reference clock, and then switch the block block in the corresponding ATM switching system. The clock distribution means 10 and the clock distribution means 20 are connected through separate cables, so that there is a disadvantage in that jitter occurs or synchronization is lost in the corresponding clock.

As described above, conventionally, the clock generation means and the clock distribution means are connected by a separate cable, there is a problem that jitter occurs in the clock input from the clock distribution means, or the clock stability due to synchronization loss is unreliable. As a plurality of clock generations or distribution boards are used, component cost and manufacturing cost increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to perform a clock generation and distribution function for a system clock required in a switch block and various matching blocks of an ATM switching system on a pattern within a board. In addition, by performing the redundancy distribution function in the triplex generation unit, it is possible to prevent the delay, jitter and wonder of the system clock and to provide a stable system clock.

1 is a block diagram illustrating a clock generation / distribution apparatus in a conventional ATM switching system.

2 is a block diagram of a clock generation / distribution apparatus in an ATM switching system according to the present invention;

3 is a detailed block diagram of a clock generation and distribution board in FIG. 2;

Explanation of symbols on the main parts of the drawings

30: clock generation board 40-1, 40-2: clock generation and distribution board

41: clock generator 42, 43: clock divider

In order to achieve the above object, a feature of the present invention is a clock generation / distribution apparatus of an ATM switching system that distributes system clocks to a switch block and various matching blocks. A clock generation board for generating and providing a synchronous reference clock with good stability and accuracy; And a redundant clock generation and distribution board for generating a system clock synchronized with the synchronization reference clock provided from the clock generation board and distributing the same to a switch block and various matching blocks.

On the other hand, the clock generation and distribution board, the clock generator for generating a system clock synchronized with the synchronization reference clock provided from the clock generation board; The apparatus may further include a redundant clock divider that receives a system clock from the clock generator and distributes the system clock to a switch block and various matching blocks through an interface between modules.

Another aspect of the present invention is a clock generation / distribution method of an ATM switching system that distributes system clocks to switch blocks and various matching blocks, wherein the clock generation board generates a synchronous reference clock and duplicates the clock generation and distribution board. The clock generation unit of each clock generation and distribution board generates a system clock synchronized with the synchronous reference clock provided from the clock generation board, and provides the clock clock to the redundant clock distribution unit. Generating a triplex clock by the distribution board; Distributing the system clock provided from the clock generator through an interface between modules, and outputting the corresponding system clock through a predetermined number of ports to distribute the redundant clock to the corresponding switch block and various matching blocks. .

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The clock generation / distribution apparatus in the ATM switching system according to the present invention includes one clock generation board 30 and two clock generation and distribution boards 40-1 to 40-2 as shown in FIG. 2. It is made.

The clock generation board 30 is interfaced with each of the clock generation and distribution boards 40-1 and 40-2, and receives an external synchronization reference clock to generate a synchronization reference clock with good stability and accuracy in a DP-PLL synchronization method. To the respective clock generation and distribution boards 40-1 and 40-2.

Each of the clock generation and distribution boards 40-1 and 40-2 distributes the synchronous reference clock provided from the clock generation board 30 to the switch block and various matching blocks, as shown in FIG. 3. And a clock generator 41 and two clock dividers 42 and 43. The clock generator 41 is a system clock synchronized with a synchronous reference clock provided from the clock generator board 30. To the respective clock distribution units 42 and 43, and each of the clock distribution units 42 and 43 receives a system clock from the clock generator 41 and switches through the interface between modules. Distribute to various matching blocks.

Referring to the clock generation and distribution operation in the ATM switching system according to the present invention configured as described above are as follows.

First, the clock generation board 30 generates a stable and accurate synchronization reference clock using a DP-PLL synchronization method by using an external synchronization reference clock provided from the outside and an oscillation clock of a self-correcting oscillator. 40-1 and 40-2, and the clock generator 41 of each of the clock generation and distribution boards 40-1 and 40-2 corresponds to the synchronous reference clock provided from the clock generation board 30. Synchronized system clock is generated and provided to each clock distribution unit 42, 43, so that it is tripled by the corresponding clock generation board 30 and two clock generation and distribution boards 40-1 and 40-2. In this case, the clock generation board 30 performs a master function of providing a synchronous reference clock to each of the clock generation and distribution boards 40-1 and 40-2. The generation and distribution boards 40-1 and 40-2 perform a slave function.

On the other hand, the clock distribution unit (42, 43) of the clock generation and distribution board (40-1, 40-2) is a switch block and the system clock (clock) provided from the clock generator 41 through the interface between modules and In this case, the clock distribution units 42 and 43 output the system clocks in pairs through a predetermined number of ports and provide them to the corresponding switch blocks and various matching blocks. The two clock generation and distribution boards 40-1 and 40-2 perform redundant clock distribution functions.

That is, the clock generation and distribution boards 40-1 and 40-2 that perform the clock generation and clock distribution functions of the highly accurate synchronous reference clock in the clock generation board 30 among the boards that perform the tripled clock generation function. By reducing the synchronization loss, the cell loss rate is reduced, and the clock generation and distribution boards 40-1 and 40-2 that perform the corresponding redundant clock distribution functions are distributed to switch blocks and various matching blocks. The number of clock output ports is increased, allowing stable clock distribution in ATM systems and systems requiring network clocks.

In addition, the clock generator 42 and 43 are included in the clock generation and distribution boards 40-1 and 40-2 to distribute clocks with stable impedance and noise.

As described above, the present invention performs a clock generation and distribution function for the system clock required in the switch block and various matching blocks of the ATM switching system on a pattern within a board, and by performing a redundant distribution function in the triple generation unit Therefore, it is possible to prevent the delay, jitter and wonder of the system clock, thereby providing a stable system clock.

Claims (3)

A clock generation / distribution apparatus of an ATM switching system for distributing system clocks to switch blocks and matching blocks, A clock generation board that receives an external synchronization reference clock and generates and provides a stable and accurate synchronization reference clock in a DP-PLL synchronization manner; Clock generation / distribution in an ATM switching system, comprising: a redundant clock generation and distribution board for generating a system clock synchronized with a synchronization reference clock provided from the clock generation board and distributing it to switch blocks and various matching blocks; Device. The method of claim 1, The clock generation and distribution board may include: a clock generator for generating a system clock synchronized with a synchronous reference clock provided from the clock generation board; And a redundant clock divider configured to receive a system clock from the clock generator and distribute the divided system to a switch block and various matching blocks through an interface between modules. A clock generation / distribution method of an ATM switching system that distributes system clocks to switch blocks and matching blocks, A clock generation board generates a synchronization reference clock to provide a redundant clock generation and distribution board, and a clock generator of each clock generation and distribution board generates a system clock synchronized with the synchronization reference clock provided from the clock generation board. Generating a redundant clock by the clock generation board and the two clock generation and distribution boards; Distributing a system clock provided from the clock generator through an interface between modules, and dually outputting a corresponding system clock through a predetermined number of ports to distribute a redundant clock to a corresponding switch block and various matching blocks. A clock generation / distribution method in an ATM switching system.