Seagate ST973402SS, ST9146802SS manual Receive eye mask, Jitter tolerance masks

9.5.2.1.2Receive eye mask

Figure 15 describes the receive eye mask. This eye mask applies to jitter after the application of a single pole high-pass frequency-weighting function that progressively attenuates jitter at 20 dB/decade below a frequency of ((bit rate) / 1.667).

Absolute amplitude (in V)

Z2

Z1

0 V

-Z1

-Z2

0 X1 X2 1-X1 1

1-X2

Normalized time (in UI)

Figure 15. Receive eye mask

Verifying compliance with the limits represented by the receive eye mask should be done with reverse channel traffic present in order that the effects of crosstalk are taken into account.

9.5.2.1.3Jitter tolerance masks

Figure 16 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			(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 16. Reveive tolerance eye mask

62 Savvio 10K.2 SAS Product Manual, Rev. D