JPH01228229A - Frame synchronizing system - Google Patents

Abstract

PURPOSE:To automatically recover a state to a normal state by taking majority by using three elastic memories. CONSTITUTION:The three elastic memories 2 are arranged in parallel, and a comparator 3 and a selector 4 are provided, A digital input signal 5 transmitted from an opposite device in an arbitrary frame phase is received, and the frame synchronization of the input signal 5 is established by a frame synchronization circuit 1, and a frame synchronization signal 6 is outputted. The input signal 5 is written on each of the three elastic memories 2 which receive the same control by the frame synchronization signal 6, respectively. Three output signals 7 read out from the elastic memories 2 are compared by the comparator 3, then, coincidence/noncoincidence is detected. And the majority of detected results is taken by the selector 4, and either the three output signals 7 is selected, then, is outputted as an output signal 8.

Description

[Detailed description of the invention] [Industrial application field] The present invention is utilized in the field of digital data communications.

The present invention relates, in the field of digital data communications, to a frame synchronization system having an elastic memory that converts a digital signal arriving at an arbitrary phase into a reference frame phase within a device.

〔overview〕

The present invention provides a frame synchronization method having an elastic memory that converts the phase of an input signal into a reference frame phase within the device, in which three of the elastic memories are arranged in parallel, and coincidence and mismatch of their output signals is detected. However, by selecting one of the three output signals as the output signal based on a majority vote of the detected results, even if one elastic memory fails, it can be automatically restored to normal state. This is what I did.

[Conventional technology]

In the conventional frame synchronization method, one elastic memory was used to perform the conversion to the internal phase of the device.

[Problem that the invention seeks to solve]

The above-described conventional frame synchronization method can notify an abnormality in case of a failure of a cell in an elastic memory, but has the drawback that it cannot be recovered unless the elastic memory is replaced.

An object of the present invention is to provide a frame synchronization method that can automatically restore the normal state even if the elastic memory fails by eliminating the above-mentioned drawbacks.

[Means for solving problems]

The present invention provides a frame synchronization method including an elastic memory that converts the phase of an input signal into a reference frame phase within the device, in which three elastic memories are arranged in parallel, and the output signal of each elastic memory is and a selection means for outputting one of the output signals by majority vote based on the detection result of the comparison means.

[Effect]

Three elastic memories are arranged in parallel, and a comparison means detects whether or not the three output signals from each elastic memory match. Then, the selection means takes a majority vote on the detection results and outputs any one of the three output signals as an output signal.

Therefore, even if one elastic memory fails, it is possible to switch to another elastic memory and automatically restore the normal state.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.

The figure is a block diagram showing the main parts of an embodiment of the present invention.

This embodiment includes a frame synchronization circuit 1 that establishes frame synchronization of an input signal 5 and outputs a frame synchronization signal 6, and three circuits that convert the phase of the input signal 5 into a reference frame phase within the device using the frame synchronization signal 6. an elastic memory 2 and a comparator 3 as a comparison means for detecting coincidence or mismatch between the output signal 7 of each elastic memory 2;
It includes a selector 4 as a selection means that outputs any one of the three output signals 7 as an output signal 8 based on a majority vote based on the detection result of the comparator 3.

The feature of the present invention is that in the figure, elastic memory 2
The reason is that three of them are arranged in parallel, and a comparator 3 and a selector 4 are provided.

Next, the operation of this embodiment will be explained. A digital input signal 5 transmitted with an arbitrary frame phase from the opposite device is received, a frame synchronization circuit 1 establishes frame synchronization of the input signal 5, and outputs a frame synchronization signal 6.

The input signal 5 is written into each of the three elastic memories 2 which are under the same control by the frame synchronization signal 6.

The three output signals 7 read from each elastic memory 2 are compared by a comparator 3 to detect coincidence and mismatch. Then, the selector 4 takes a majority vote of the detection results, and one of the three output signals 7 is selected and output as the output signal 8.

〔Effect of the invention〕

As explained above, the present invention uses three elastic memories, so that when one elastic memory fails, it can be automatically switched to another elastic memory that is operating normally. This has the effect of restoring normal conditions.

[Brief explanation of the drawing]

The figure is a block diagram showing the main parts of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Frame synchronization circuit, 2... Elastic memory, 3... Comparator, 4... Selector, 5...
...Input signal, 6...Frame synchronization signal, 7...(
Elastic memory) output signal, ... output signal.

Claims (1)

[Claims] 1. In a frame synchronization method including an elastic memory that converts the phase of an input signal into a reference frame phase within the device, three elastic memories (2) are arranged in parallel, Comparing means (3) for detecting coincidence and mismatch of output signals of each elastic memory; and selecting means (4) for outputting one of the output signals by majority vote based on the detection result of the comparing means. A frame synchronization method characterized by including.