Seagate ST973451SS, ST936751SS manual Maximum allowable jitter, Receiver jitter tolerance

9.5.2.3.1Jitter

Table 19 defines the maximum allowable jitter.

Table 19: Maximum allowable jitter

1.5 Gbps m, n		3.0 Gbps m, n
Deterministic jitterq	Total jitterc,d,e,f	Deterministic jittere	Total jitterc,d,e,f
0.35	0.55	0.35	0.55

aUnits are in UI.

bThe values for jitter in this section are measured at the average amplitude point.

cTotal jitter is the sum of deterministic jitter and random jitter. If the actual deterministic jitter is less than the maximum specified, then the random jitter may increase as long as the total jitter does not exceed the specified maximum total jitter.

dTotal jitter is specified at a probability of 10-12.

eThe deterministic and total values in this table apply to jitter after 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).

fIf total jitter received at any point is less than the maximum allowed, then the jitter distribution of the signals is allowed

to be asymmetric. The total jitter plus the magnitude of the asymmetry shall not exceed the allowed maximum total jitter. The numerical difference between the average of the peaks with a BER < 10-12and the average of the individual events is the measure of the asymmetry. Jitter peak-to-peak measured < (maximum total jitter - Asymmetry).

9.5.2.3.2Receiver jitter tolerance

Table 20 defines the amount of jitter the receiver shall tolerate .

Table 20:	Receiver jitter tolerance
1.5 Gbpsa				3.0 Gbpsa
Sinusoidal		Deterministic	Total	Sinusoidal	Deterministic	Total
jitterb,c		jittere,f,h	jitterh	jitterb,d	jittere,g,h	jitterh
0.10		0.35	0.65	0.10	0.35	0.65

aUnits are in UI.

bThe jitter values given are normative for a combination of deterministic jitter, random jitter, and sinusoidal jitter that receivers shall be able to tolerate without exceeding a BER of 10-12. Receivers shall tolerate sinusoidal jitter of progressively greater amplitude at lower frequencies, according to the mask in figure 18 with the same deterministic jitter and random jitter levels as were used in the high frequency sweep.

cSinusoidal swept frequency: 900 kHz to > 5 MHz.

dSinusoidal swept frequency: 1.800 kHz to > 5 MHz.

eNo value is given for random jitter. For compliance with this standard, the actual random jitter amplitude shall be the value that brings total jitter to the stated value at a probability of 10-12. The additional 0.1 UI of sinusoidal jitter is added to ensure the receiver has sufficient operating margin in the presence of external interference.

fDeterministic jitter: 900 kHz to 750 MHz.

gDeterministic jitter: 1.800 kHz to 1.500 MHz.

hThe deterministic and total values in this table apply to jitter after 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).

9.5.2.3.3Compliant jitter test pattern (CJTPAT)

The CJTPAT within a compliant protocol frame is used for all jitter testing unless otherwise specified. See the SAS Interface Manual for definition of the required pattern on the physical link and information regarding spe- cial considerations for scrambling and running disparity.

64 Savvio 15K SAS Product Manual, Rev. B