Electric Network Frequency (ENF)
Definition
The instantaneous frequency of the alternating-current mains supply, nominally 50 Hz in most of the world and 60 Hz in North America. It fluctuates continuously around the nominal value in a pattern driven by supply-demand imbalances on the grid.
Related terms
- Cross-Correlation
- A statistical measure of the similarity between two time series as a function of a time lag. In ENF matching, the extracted...
- ENF Reference Database
- A continuously maintained archive of grid frequency measurements recorded at high temporal resolution, used as the ground truth against which a recording's...
- Camera Flicker / Optical ENF
- The periodic brightness variation captured in video recorded under mains-powered fluorescent or LED lighting. The lighting modulates at 100 Hz or 120...
- ENF Discontinuity
- A break in the continuity of the extracted ENF trace that is inconsistent with the reference database. Can indicate a deletion (missing...
- ENF Splice Detection
- Using breaks or discontinuities in the ENF time series to identify edits, cuts, or inserted segments in a recording. A genuine unedited...
- Geographic Grid Disambiguation
- The process of determining which national or regional grid a recording's ENF trace came from, since the 50 Hz grids of continental...
- Short-Time Fourier Transform (STFT)
- A signal processing technique that applies a Fourier transform to successive short windows of a signal, producing a time-frequency representation. Used in...
- Transmission System Operator (TSO)
- The entity responsible for operating a high-voltage electricity transmission network in a given country or region. TSOs log grid frequency in real...
Explained in these topics
- Audio Authentication and the Electric Network Frequency MethodThe instantaneous frequency of the alternating-current mains supply, nominally 50 Hz in most of the world and 60 Hz in North America. It fluctuates continuousl...
- Electric Network Frequency Analysis for Audio DatingThe instantaneous frequency of a national or regional power grid, nominally 50 Hz or 60 Hz but continuously varying. The pattern of these variations, logged by...