Recent detection schemes use clock- less over sampling techniques in which the receiver compares bits sampled at several times the bit rate.Physical Layer Testing of PCI-Express Signals Using Consecutive Bits LeCroy Corporation Booth 600 Intel Developers Forum Press and Analyst Dr. Michael Lauterbach, Director, Product Management Introduction Traditionally, serial data signals such as Fibrechannel and Infiniband have used recovered clocks in their receiver circuits to detect the incoming data bits. More recent detection schemes use clock-less over sampling techniques in which the receiver compares bits sampled at several times the bit rate. The bits from each phase of the over sampled signal are then polled to determine the correct bit values. The development of the serial ATA standard and now PCI-Express, account for these different detection schemes through specification of the use of consecutive UI in the measurement of bo……