FPGA signal processing using sigma-delta modulation

FPGA devices maintain the flexibility of software-based solutions, while providing levels of performance that match, and often exceed ASIC solutions. There is a rich and expanding body of literature devoted to the efficient and effective implementation of digital signal processors using FPGA-based hardware. More often than not, the most successful of these techniques involves a paradigm shift away from the methods that provide good solutions in software programmable DSP systems. This article reports on the rich set of design opportunities that are available to the signal processing system designer through innovative combinations of ΣΔ modulation techniques and FPGA signal processing hardware. The applications considered include narrow-band filters, both single-rate and multi-rate; DC canceller; and ΣΔ modulation hybrid digital-analog control loops for simplifying carrier recovery, timing recovery, automatic gain control (AGC) loops in a digital communication receiver