The Electrical Network Frequency Criterion: Determining The Time And Location Of Digital Recordings

The topic of this thesis is the Electrical Network Frequency (ENF) Criterion as a method to determine both the time of recording and the location of an audio file when no or corrupted meta-data is available. This may be possible when the recording equipment is mains powered or when it is situated in electromagnetic field of the power grid. Then the voltage signal is unintentionally recorded as well and its frequency is uniquely changing over time and location. In this sence, the ENF is like a digital fingerprint. It is found that a time of recording can be estimated under reasonable circumstances and that a rough location estimation of the recording is possible. The ENF criterion is applied mostly in forensic research. The applicability is limited by acoustic noise and audio filters.Numerical AnalysisApplied mathematicsElectrical Engineering, Mathematics and Computer Scienc