Automatic skew correction for differential signals
AssigneeWarpspeed Chips, LLC
InventorArnold M. Frisch
Life of this patent
Estimating the term…
Abstract
A skew correction system incorporated into a transmitter forwarding a differential signal on a differential lane monitors returning signal reflections when the receiving end of the differential lane is appropriately terminated. Based on an analysis of the reflections, the skew correction system adjusts the relative timing of complementary edges of the differential signal departing the transmitter so as to substantially eliminate skew at the receiving end of the differential lane.
Claims15
For a differential lane forwarding a differential signal arriving at its transmitting end to its receiving end, the differential lane being terminated at its receiving end such that any skew in the differential signal causes reflections of the differential signal to return from the receiving end to the transmitting end, an apparatus for reducing skew in the differential signal at the receiving end, the apparatus comprising:
- a skew adjuster circuit for adjustably skewing the differential signal at the transmitting end, and
- a skew detection circuit for monitoring reflections of the differential signal at the transmitting end and for signaling the skew adjuster circuit co adjust skew in the differential signal at the transmitting end so as to reduce skew in the differential signal at the receiving end, thereby reducing reflections in the differential signal at the transmitting end.
For a differential lane forwarding a differential signal arriving at its transmitting end to its receiving end, a method for reducing skew in the differential signal at the receiving end, the method comprising the steps of:
- a. terminating the differential lane at its receiving end with a differential termination such that any skew in the differential signal causes reflections of the differential signal to return from the receiving end to the transmitting end,
- b. detecting reflections of the differential signal at the transmitting end, and
- c. adjusting skew in the differential signal at the transmitting end of the differential lane in response to reflections detected at step b so as to reduce skew in the differential signal at the receiving end of the differential lane.
Dependencies are inferred from the claim text.