Research Article
Acoustic Self-Calibrating System for Indoor Smart Phone Tracking
Table 1
Difference between average hearing threshold and sound pressure level emitted by smart phones in units of the standard deviation.
| Distance to smart phone | Smart phone type | 18 kHz | 20 kHz |
| 1 cm | iPhone 4S | 1.6 | 5.0 | Samsung GT-S5830 | 0.9 | 4.1 | iPod Touch | 1.0 | 4.4 |
| 10 cm | iPhone 4S | 1.9 | 6.4 | Samsung GT-S5830 | 1.8 | 4.1 | iPod Touch | 1.7 | 4.1 |
| 5 m | iPhone 4S | 3.5 | 11.7 | Samsung GT-S5830 | 3.4 | 12.0 | iPod Touch | 3.5 | 11.3 |
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