9.5.2.2Transmitter signal characteristics

Table 16 specifies the signal requirements at the transmitter end of a TxRx connection as measured into the zero-length test load. All specifications are based on differential measurements.

The OOB sequence is performed at signal voltage levels corresponding to the lowest supported transfer rate. Table 16 specifies the signal characteristics.

Table 16: Transmitter signal characteristics

Signal characteristica

Units

1.5 Gbps

3.0 Gbps

Skewb

ps

20

15

Tx Off Voltagec

mV(P-P)

< 50

< 50

Maximum rise/fall timed

ps

273

137

Minimum rise/fall timed

ps

67

67

Maximum transmitter output imbalancee

%

10

10

OOB offset deltaf

mV

± 25

± 25

OOB common mode deltag

mV

± 50

± 50

aAll tests in this table shall be performed with zero-length test load shown in figure 20.

bThe skew measurement shall be made at the midpoint of the transition with a repeating 0101b pattern on the physical link. The same stable trigger, coherent to the data stream, shall be used for both the Tx+ and Tx- signals. Skew is defined as the time difference between the means of the midpoint crossing times of the Tx+ signal and the Tx- signal.

cThe transmitter off voltage is the maximum A.C. voltage measured at compliance points when the transmitter is unpowered or transmitting D.C. idle (e.g., during idle time of an OOB signal).

dRise/fall times are measured from 20 % to 80 % of the transition with a repeating 0101b pattern on the physical link.

eThe maximum difference between the V+ and V- A.C. RMS transmitter amplitudes measured on a CJTPAT test pattern (see 9.5.2.3.3) into the test load shown in figure 20, as a percentage of the average of the V+ and V- A.C. RMS amplitudes.

fThe maximum difference in the average differential voltage (D.C. offset) component between the burst times and the idle times of an OOB signal.

gThe maximum difference in the average of the common mode voltage between the burst times and the idle times of an OOB signal.

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Seagate ST3750630SS, ST31000640SS, ST3500620SS manual Transmitter signal characteristics

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