| 摘要 |
A multi-edge clock recovery method is provided that may be used with data streams having at least three (3) levels. According to the invention, when each threshold is crossed, it generates data edges for that particular threshold. These data edges latching the polarity of the recoverd clock at the time the corresponding threshold was crossed, thereby indicating the "late" and "early" edge information for that threshold crossing with respect to the falling edge of the recovered clock. Immediately following the decoding of the most recent multi-level symbol, the appropriate threshold for the data transition is determined. The decoded values of the sumbols preceding and following the data edges determine which threshold should be selected for "late" and "early" edge indications. The recorded late/early data edge status for this selected threshold is then used for determining when it is necessary to correct the phase of the recovered clock. If clock phase correction required, it is done so prior to the next falling edge of recovered clock to avoid corrupting the next "late" or "early" edge data with the "old" phase of recovered clock.
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