Channel skew identification and notification

摘要

Embodiments of the present invention analyze a plurality of parallel channels and identify specific channel(s) that have skew outside of an acceptable skew error margin. In certain embodiments, this skew is identified by determining the timing misalignment between a channel under test and a deskew channel. Other channels within the plurality of channels are masked by transmitting a repeating masked bit pattern. This timing misalignment may be measured by comparing a segment within the channel under test to a corresponding segment within the deskew channel and identifying a time differential between the two segments.

主权项

1. A method comprising:
operating a demultiplexer in a first mode and a second mode, the demultiplexer having a plurality of outputs; in the first mode, the demultiplexer receives a client signal and supplies each of plurality of portions of the client signal at a respective one of the plurality of outputs, and in the second mode:
the demultiplexer transmits a first bit sequence on a first channel supplied from a first one of the plurality of outputs of the demultiplexer, within a plurality of channels, the first bit sequence having a first width, which is greater than a width of a skew error margin,the demultiplexer transmits each of a plurality of data streams on a corresponding one of a group of channels, within the plurality of channels, each of the plurality of data streams including a repeating second bit sequence, the second bit sequence having a second width, which is less than the width of the skew error margin, each of the plurality of data streams being output from a corresponding one of remaining ones of the plurality of outputs of the demultiplexer, the repeating second bit sequence being input to the demultiplexer, andthe demultiplexer transmits successive bit segments on a second channel, within the plurality of channels, each of the bit segments is a copy of a portion of a respective one of the plurality data streams, such that one of the bit segments includes a portion of the first bit sequence, each said copy of the portion of the respective one of the plurality of data streams having a third width, which is greater than the skew error margin; measuring a skew value between the first bit sequence and said one of the bit segments; and generating an alarm if the skew value is greater than the skew error margin, the alarm including an identifier that identifies the first channel.