On the reconstruction of bandlimited signals from random samples quantized via noise-shaping

Abstract: Noise-shaping quantization techniques are widely used for converting bandlimited signals from the analog to the digital domain. They work by "shaping" the quantization noise so that it falls close to the reconstruction operator's null space. We investigate the compatibility of two such schemes, specifically $\Sigma\Delta$ quantization and distributed noise-shaping quantization, with random samples of bandlimited functions. Let $f$ be a real-valued $\pi$-bandlimited function. Suppose $R>1$ is a real number and assume that ${x_i}{i=1}^m$ is a sequence of i.i.d random variables uniformly distributed on $[-\tilde{R},\tilde{R}]$, where $\tilde{R}>R$ is appropriately chosen. We show that by using a noise-shaping quantizer to quantize the values of $f$ at ${x_i}{i=1}^m$, a function $f^{\sharp}$ can be reconstructed from these quantized values such that $|f-f^{\sharp}|_{L^2[-R, R]}$ decays with high probability as $m$ and $\tilde{R}$ increase. We emphasize that the sample points ${x_i}_{i=1}^m$ are completely random, i.e., they have no predefined structure, which makes our findings the first of their kind.