In this project, we focused on the DMA algorithm in order to create a frequency independent beam-pattern. In the first part of this project, we built a demo station which enables us to record, analyze and test the theory in practice.
At the first stage, we designed physical arrays, linear and circular so that every geometry contained a number of omni-microphones according to the design.
In order to perform spatial recordings (to get a beampattern), we planned a circular spinning infrastructure with a single degree resolution which enables us to record from different angles. The microphone arrays were connected to a synchronous AtoD sampler, and the sampler’s output was connected to a PC which handles the signal processing and analysis by a simulation system that supports the different geometries and microphones.
The software system was designed to run under three modes of operation: simulation, recording and offline analysis. The data is recorded so we can analyze the result off-line. The simulation system, written in MATLAB has a GUI which allows the user to see all different parameters of the algorithm, such as directivity, SNR, gain, white noise gain etc., and to hear the reconstructed signal in a specific algorithm compared the original one.
In the second part of this project, we performed calibration and adjustments to the system in order to improve the it’s performance. In the integration phase, we encountered challenges due to model errors e.g.: delay and gain errors. This integration phase turned up to take a major part of the second stage, during which we analyzed the effects of various aspects of the model errors on the system’s performance and found solutions to compensate these errors in order to reach optimal results. After the integration phase, we recorded different scenarios: speech signals, songs, beampattern and multiple sources recordings. At the final stage, we performed analysis on the recorded results and reached a number of beampattern reconstructions. We compared the performance of both DMA and DS algorithms and demonstrated live examples of the different algorithms performance with noise reduction of 2 sources scenario.
Eventually, we managed to achieve results that demonstrate what we expected to receive using DMA according to the theory.