Seagate ST3450856SS, ST3146356SS Receive eye mask, Jitter tolerance masks, Absolute amplitude

9.5.2.1.2Receive eye mask

Figure 17 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

0V

-Z1

-Z2

0X1 X2 1-X1 1

1-X2

Normalized time (in UI)

Figure 17. 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 18 describes the receive tolerance eye masks and is constructed using the X2 and Z2 values given in

table 18. X1OP is half the value for total jitter intable 18 and X1TOL is half the value for total jitter in table 19, for jitter frequencies above ((bit rate) / 1.667).

Absolute amplitude (in V)

Z2

Z1OP

Z1TOL

0 V

-Z1TOL -Z1OP

-Z2

(additional sinusoidal jitter) / 2

Outline of eye mask before adding sinusoidal jitter

Outline of eye mask after adding sinusoidal jitter

0 X1OP	X2	1
		1-X1OP
X1TOL		1-X1TOL

Normalized time (in UI)

Figure 18. Receive tolerance eye mask

Cheetah 15K.6 SAS Product Manual, Rev. A 65