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Bachelor-Vortrag: Robust Delay Estimation for Feedback Systems
Dienstag, 12. November 2019
Feedback occurs when an output signal is fed back into a system as part of the input signal. Thus, acoustical feedback takes place when there's a transducer, such as a microphone in immediate vicinity of a loudspeaker, The fed back signal may negatively impact the audio quality of the output signal, since the superposition of the input signal and a time delayed copy of the same signal may create unwanted howling effects.
In the scope of this bachelor's thesis, acoustical feedback in IP-based teleconferencing systems, e.g., a conference call which is transmitted over the internet is considered. In order for feedback to occur, at least two users of the same conference call will have to be in proximity of each other, with at least one caller using the loudspeaker. The output signal will be detected by the microphone, transmitted and thus delayed over Internet Protocol, before then being played back as part of the input signal.
This thesis aims at implementing an algorithm that detects when howling artefacts occur and also determines their frequencies. Essential in achieving this, is the realisation of a transmission delay estimating function.