What avDMF does : Departures
Departure: the aircraft emits an ADS-B signal to the receivers (up to three) and makes noise that the sound level meters record (at least one per logical runway); avDMF matches the two and produces everything above.
What avDMF does : Arrivals
Landing: the noise of the aircraft is recorded by the sound level meters (up to three); avDMF matches it to the flight and produces everything above.