Seagate ST3400755SS manual Receive eye mask, Jitter tolerance masks, Absolute amplitude

9.5.2.1.2Receive eye mask

Figure 30 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 30. 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 31 describes the receive tolerance eye masks and is constructed using the X2 and Z2 values given in

table 16. X1OP is half the value for total jitter intable 16 and X1TOL is half the value for total jitter in table 17, 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 31. Receive tolerance eye mask

Cheetah NS SAS Product Manual, Rev. B 57