| 摘要 |
Methods and apparatus to enforce a power off state of an audience measurement device during shipping of the device are disclosed herein. An example portable audience measurement device includes a housing, a media detector in the housing to collect media exposure data, and a packaging sensor to receive an audio signal. A packaging detector generates a frequency spectrum of the detected audio signal, determines an energy of a first frequency associated with the generated frequency spectrum, determines an energy of a second frequency higher than the first frequency and associated with the generated frequency spectrum, and compares the difference between the energy of the first frequency and the second frequency to a muffling threshold to determine whether the device is located within a package. |
