Method and apparatus for receiving data

A method to asynchronously receive a stream of data comprising:

• detecting a plurality of edges within the stream of data;
• tracking a transmitted clock with a plurality of locally-generated clock phases;
• determining whether each edge arrives early or late relative to an expected arrival time;
• using the determination whether an edge arrived early or late in a receiver decision process;
• qualifying the plurality of detected edges for use in subsequent processing using historical information;
• and
• incrementing a count in a counter, one counter for each of the plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

A method to asynchronously receive a stream of data comprising:

• detecting a plurality of edges within the stream of data;
• tracking a transmitted clock with a plurality of locally-generated clock phases;
• determining whether each edge arrives early or late relative to an expected arrival time;
• using the determination whether an edge arrived early or late in a receiver decision process;
• qualifying the plurality of detected edges for use in subsequent processing using historical information;
• and
• assigning a counter for each of the plurality of locally-generated clock phases, incrementing a particular counter associated with a particular clock phase each time a qualified detected edge is closest in time to said particular clock phase and determining a moving average phase of the qualified detected edges based on values in the counter.

A method to asynchronously receive a stream of data comprising:

• detecting a plurality of edges within the stream of data;
• tracking a transmitted clock with a plurality of locally-generated clock phases;
• determining whether each edge arrives early or late relative to an expected arrival time;
• using the determination whether an edge arrived early or late in a receiver decision process;
• qualifying the plurality of detected edges for use in subsequent processing using historical information;
• and
• assigning a counter for each of the plurality of locally-generated clock phases, incrementing a particular counter associated with a particular clock phase each time a qualified detected edge is closest in time to said particular clock phase, said selecting one of the plurality of locally-generated clock phases whose assigned counter is a maximum as a moving average phase of the qualified detected edges.

An apparatus to recover a clock from a stream of data comprising:

• a) an edge buffer to receive the data stream and output an edge signal that indicates detection of a plurality of edges within the data stream;
• b) an edge processor coupled to the edge buffer to determine an average phase of the detected edges and output a data signal and the average phase;
• c) a multi-phase clock coupled to the edge processor to output a plurality of clock phases offset from each other by a predetermined amount;
• and
• d) an elastic buffer coupled to the edge processor and the multi-phase clock to output the data and the average phase.

An asynchronous receiving method to receive a data stream in a received waveform comprising:

• detecting a plurality of edges of the received waveform;
• using a local clock to determine an average phase of the plurality of edges of the received waveform;
• predicting a time when a next edge should be received based on the calculated average and determining whether the next edge was received early or late relative to the predicted time;
• and
• incrementing a count in a counter, one counter for each of a plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

An apparatus to recover a clock from a stream of data encoded as a positive differential signal and a negative differential signal, comprising:

• a) an edge buffer to receive the positive and negative differential signals and output a positive zero crossing signal to indicate an occurrence of a rising edge of the positive differential signal and a negative zero crossing signal to indicate an occurrence of a rising edge of the negative differential signal;
• b) an edge processor coupled to the edge buffer to determine an average phase of the positive and negative zero crossing signals and output a data signal and the average phase;
• and
• c) a multi-phase clock coupled to the edge processor to output a plurality of clock phases offset from each other by a predetermined amount.

A computer system including a plurality of modular components communicating with each other, each of the modular components employing an asynchronous receiving method to receive a data stream from another modular component, said asynchronous receiving method comprising:

• detecting a plurality of edges within the stream of data;
• tracking a transmitted clock with a plurality of locally-generated clock phases;
• determining whether each edge arrives early or late relative to an expected arrival time;
• using the determination whether an edge arrived early or late in a receiver decision process;
• and
• incrementing a count in a counter, one counter for each of the plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

A communications system including a plurality of components communicating with each other, each of the components employing an asynchronous receiving method to receive a data stream from another component, said asynchronous receiving method comprising:

• detecting a plurality of edges within the stream of data;
• tracking a transmitted clock with a plurality of locally-generated clock phases;
• determining whether each edge arrives early or late relative to an expected arrival time;
• using the determination whether an edge arrived early or late in a receiver decision process;
• and
• incrementing a count in a counter, one counter for each of the plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

A method to receive a stream of data comprising:

• detecting a plurality of edges within the stream of data;
• generating a plurality of locally-generated clock phases;
• tracking at least some of the edges with the locally-generated clock phases;
• selecting one of the plurality of locally-generated clock phases based upon the tracking;
• and
• incrementing a count in a counter, one counter for each of the plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

An asynchronous receiving method to receive a data stream in a received waveform comprising:

• detecting a plurality of edges of the received waveform;
• using a local clock to determine an average phase the plurality of edges of the received waveform;
• and
• incrementing a count in a counter, one counter for each of a plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.

An asynchronous receiving method to receive a data stream in a received waveform comprising:

• detecting a plurality of edges of the received waveform;
• outputting a data stream based upon the detected plurality of edges;
• and
• incrementing a count in a counter, one counter for each of a plurality of locally-generated clock phases, every time a qualified detected edge is closest to one of the plurality of locally-generated clock phases and determining an average phase of the qualified detected edges based on the counts in the counter.