Seagate Enterprise Value manual Acoustics, Test for Prominent Discrete Tones PDTs

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2.9Acoustics

Drive acoustics are measured as overall A-weighted acoustic sound power levels (no pure tones). All measurements 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 3 Fluid Dynamic Bearing (FDB) motor acoustics

	Idle*	Performance Seek
4 Disks	2.3 bels (typical)	2.8 bels (typical)
(4TB)	2.5 bels (max)	3.0 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.

2.10Test 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.

2.11Electromagnetic immunity

When properly installed in a representative host system, the drive operates without errors or degradation in performance when subjected to the radio frequeny (RF) environments defined in Table 4.

Table 4 Radio frequency environments

Test	Description	Performance	Reference
		level	standard
Electrostatic discharge	Contact, HCP, VCP: ± 4 kV; Air: ± 8 kV	B	EN61000-4-2: 95
Radiated RF immunity	80MHz to 1,000MHz, 3 V/m,	A	EN61000-4-3: 96
	80% AM with 1kHz sine		ENV50204: 95
	900MHz, 3 V/m, 50% pulse modulation @ 200Hz
Electrical fast transient	± 1 kV on AC mains, ± 0.5 kV on external I/O	B	EN61000-4-4: 95
Surge immunity	± 1 kV differential, ± 2 kV common,	B	EN61000-4-5: 95
	AC mains
Conducted RF immunity	150kHz to 80MHz, 3 Vrms, 80% AM with 1kHz	A	EN61000-4-6: 97
	sine
Voltage dips, interrupts	0% open, 5 seconds	C	EN61000-4-11: 94
	0% short, 5 seconds	C
	40%, 0.10 seconds	C
	70%, 0.01 seconds	B

Seagate Terascale HDD Product Manual, Rev. B 14