A Residue Number System for Wideband Acousto-Optic Spectrum Analysis

Abstract

An architecture is presented which performs extremely wideband acousto-optic (AO) spectrum analysis using rf-preprocessing and smart, rapid postprocessing circuitry based on residue number theory. For k channels each with % resolution elements, where the %'s are relatively prime, the total number of possible resolution elements is given by IIm . The total rf bandwidth is folded into nk banis each % elements wide, and outputs of the k channels from the spectrum analyzer are compared to determine the frequency and intensity of signals within the system aperture. Current hardware performs A0 spectrum analysis over a 50MHz bandwidth with 25 kHz resolution. bbdifications to this hardware extends the bandwidth to a practical limit of approximately 300 MHz, maintaining the 25-kHz system resolution. Other systems are proposed for wider bandwidths, a nd the potential performance parameters for these systems are examined. The performance depends primarily on the choice of moduli T, the number of moduli k, and the number of bands nk.