<p>In forensic investigations, verification of digital recordings is an important as-pect. There are numerous methods to verify authentication of recordings, but itis difficult to determine when the media was recorded. By studying the electricalnetwork frequency, one can find a unique signature and then match the recordingto this signature. By matching a recorded signal to a database, which contains allnecessary information, one can find the time when the recording was made.</p>

In forensic investigations, verification of digital recordings is an important as-pect. There are numerous methods to verify authentication of recordings, but itis difficult to determine when the media was recorded. By studying the electricalnetwork frequency, one can find a unique signature and then match the recordingto this signature. By matching a recorded signal to a database, which contains allnecessary information, one can find the time when the recording was made.