Generic sensing hardware and real-time reconstruction for structured analog signals

Generic acquisition hardware promotes a unified treatment of various signal classes. In modern applications involving wide input bandwidths, uniform sampling, the common practice for generic digitization, leads to prohibitively large sampling and processing rates due to the wide Nyquist bandwidth of the input. In this paper, we present the X-ADC system which narrows down the input bandwidth by analog preprocessing prior to sampling at rates substantially lower than Nyquist. As we show, the X-ADC strategy is generic in the sense that multitude radio and medical imaging applications with structured signals can utilize the same architecture for low rate acquisition. A recently published sub-Nyquist hardware, which was designed according to the proposed X-ADC scheme, provides a concrete reference for the present study. We complement the generic acquisition by reporting on a real-time embedded implementation of a sub-Nyquist reconstruction algorithm. The embedded design enables, for example, fast spectrum sensing which is essential to real-time cognitive radio applications.