Seagate ST300MM0026 Savvio 10K.1 SAS Product Manual - Page 69

9.5.2.1.3 Jitter tolerance masks Figure 20 describes the receive tolerance eye masks and is constructed using the X2 and Z2 values given in table 29. X1OP is half the value for total jitter intable 29 and X1TOL is half the value for total jitter in table 30, for jitter frequencies above ((bit rate) / 1.667). Absolute amplitude (in V) (additional sinusoidal jitter) / 2 Z2 Z1OP Z1TOL 0 V -Z1TOL -Z1OP -Z2 0 X1OP X2 1 1-X1OP X1TOL 1-X1TOL Normalized time (in UI) Outline of eye mask before adding sinusoidal jitter Outline of eye mask after adding sinusoidal jitter Figure 20. Reveive tolerance eye mask The leading and trailing edge slopes of figure 19 shall be preserved. As a result the amplitude value of Z1 is less than that given in table 28 and Z1TOL and Z1OP shall be defined from those slopes by the following equa- tion: Z1TOL = Z1OP x -X----2---O----P 0---,----5---)---x---a---d---d----i-t--i-o---n----a---l---s---i-n----u---s---o---i--d---a---l---j--i-t--t-e----r--)---------X-----1---O----PX2OP - X1OP where: Z1TOL is the value for Z1 to be used for the tolerance masks; and Z1OP, X1OP, and X2OP are the values in table 28 for Z1, X1, and X2. The X1 points in the receive tolerance masks are greater than the X1 points in the receive masks, due to the addition of sinusoidal jitter. Savvio SAS Product Manual, Rev. D 63