Seagate ST936751SS, ST973451SS manual Jitter tolerance masks, Reveive tolerance eye mask

9.5.2.1.3Jitter tolerance masks

Figure 17 describes the receive tolerance eye masks and is constructed using the X2 and Z2 values given in

table 19. X1OP is half the value for total jitter intable 19 and X1TOL is half the value for total jitter in table 20, for jitter frequencies above ((bit rate) / 1.667).

Absolute
amplitude			(additional sinusoidal jitter) / 2
(in V)
Z2
Z1OP
Z1TOL
0 V			Outline of eye mask
			before adding
-Z1TOL			sinusoidal jitter
-Z1OP
-Z2			Outline of eye mask
			after adding
			sinusoidal jitter
0	X1OP	X2	1
			1-X1OP
	X1TOL		1-X1TOL

Normalized time (in UI)

Figure 17. Reveive tolerance eye mask

The leading and trailing edge slopes of figure 16 shall be preserved. As a result the amplitude value of Z1 is less than that given in table 18 and Z1TOL and Z1OP shall be defined from those slopes by the following equa- tion:

Z1TOL	X2OP – ((0, 5)xadditional sinusoidal jitter) – X1OP
	= Z1OPx---------------------------------------------------------------------------------------------------------------------------------------
	X2OP – 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 18 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 15K SAS Product Manual, Rev. B 61