Estimation of Internal Delays

Abstract

In this thesis report, the design of the estimation of internal delays within speakers and microphones will be covered. The estimation is done via an iterational algorithm which converges to the different delays. The design choice of the estimation of those delays follows from an initial attempt to improve synchronization of the Bosch DICENTIS microphone units. With an unit being a system is placed on the desk of an attendee of a conference, consisting of a microphone and a speaker. After coming to the conclusion that the current level of synchronization already sufficed the focus was shifted towards the estimation of the internal delays.

The choice of algorithm that was used for the estimation is covered in the in the state of the art analysis of the current internal delay estimation techniques. The subsystem receives pre-determined times between units and uses these to estimate the internal delays. This estimation is done with a random initialization of the delays (within reasonable margins for the delays). After which this estimation converges towards the real values by minimizing a Frobenius norm between the rank three approximation and the received times. This is elaborated on in the Estimating Internal Delays section. The algorithm can also make use of a regularization term which decreases the time required for the estimation of the delays. The results of the algorithm are discussed in the Implementation section, which consists of a number of MATLAB simulations using the implemented algorithm. Using the results, a conclusion is drawn for the viability of the solution after which a recommendation of future work is given.