Seagate ST31000340AS Acoustics, Electromagnetic immunity, Test for Prominent Discrete Tones PDTs

2.9Acoustics

Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All mea- surements are consistent with ISO document 7779. Sound power measurements are taken under essentially free-field conditions over a reflecting plane. For all tests, the drive is oriented with the cover facing upward.

Note. For seek mode tests, the drive is placed in seek mode only. The number of seeks per second is defined by the following equation:

(Number of seeks per second = 0.4 / (average latency + average access time)

Table 4:	Fluid Dynamic Bearing (FDB) motor acoustics
		Idle*	Performance Seek	Quiet Seek
ST31000340AS, ST31000640AS,		2.9 bels (typ)	3.2 bels (typ)	3.1 bels (typ)
ST3750330AS and ST3750630AS		3.1 bels (max)	3.3 bels (max)	3.2 bels (max)
ST3500320AS, ST3500620AS and		2.7 bels (typ)	3.1 bels (typ)	3.0 bels (typ)
ST3500820AS		2.9 bels (max)	3.2 bels (max)	3.1 bels (max)

*During periods of drive idle, some offline activity may occur according to the S.M.A.R.T. specification, which may increase acoustic and power to operational levels.

2.9.1Test for Prominent Discrete Tones (PDTs)

Seagate follows the ECMA-74 standards for measurement and identification of PDTs. An exception to this process is the use of the absolute threshold of hearing. Seagate uses this threshold curve (originated in ISO 389-7) to discern tone audibility and to compensate for the inaudible components of sound prior to computation of tone ratios according to Annex D of the ECMA-74 standards.

2.10Electromagnetic immunity

When properly installed in a representative host system, the drive operates without errors or degradation in performance when subjected to the radio frequency (RF) environments defined in the following table:

Table 5:	Radio frequency environments
Test		Description	Performance level	Reference standard
Electrostatic		Contact, HCP, VCP: ± 4 kV; Air: ± 8 kV	B	EN 61000-4-2: 95
discharge
Radiated RF		80 to 1,000 MHz, 3 V/m,	A	EN 61000-4-3: 96
immunity		80% AM with 1 kHz sine		ENV 50204: 95
		900 MHz, 3 V/m, 50% pulse modulation @ 200 Hz
Electrical fast		± 1 kV on AC mains, ± 0.5 kV on external I/O	B	EN 61000-4-4: 95
transient
Surge immunity		± 1 kV differential, ± 2 kV common, AC mains	B	EN 61000-4-5: 95
Conducted RF		150 kHz to 80 MHz, 3 Vrms, 80% AM with 1 kHz sine	A	EN 61000-4-6: 97
immunity
Voltage dips,		0% open, 5 seconds	C	EN 61000-4-11: 94
interrupts		0% short, 5 seconds	C
		40%, 0.10 seconds	C
		70%, 0.01 seconds	B

Barracuda 7200.11 Serial ATA Product Manual, Rev. C 15