Wavefront Generation Using a Dense Array and Multidimensional ΔΣ Modulation

We propose a new digital to analogue (DA) conversion technique for acoustical transducer arrays. This technique utilizes the multidimensional band-limited property of array signals. Using the technique, a large dynamic-range wavefront is converted to multiple 1-bit waveforms which are over-sampled temporally and spatially. The 1-bit waveforms are fed into a dense array of transducers. The acoustical wavefront transmitted from the array is approximately equal to the original wavefront, because the spatial high frequency components are eliminated by band-limitation due to wave propagation. This paper describes an over-sampling technique using two dimensional (2-D) ΔΣ modulation for 1-D and 2-D arrays. Results of simulations are presented for evaluation and demonstration of the applicability of the proposed method.