A Parameterizable Chisel Generator of Numerically Controlled Oscillators for Direct Digital Synthesis

Abstract

Numerically controlled oscillators (NCOs) as part of direct digital synthesizers (DDS) are important components in many digital communication subsystems, such as various digital modulation and demodulation schemes, up and down converters, radar, sonar and laser appliances, etc. The vast number of their beneficial characteristics is what makes NCOs so widely used. Taking this into account, a parameterizable generator of numerically controlled oscillators is implemented using Chisel hardware design language. The proposed generator provides a broad range of parameter configurations, such as input and output data types and widths, the number of different output samples, optional use of spur-reducing techniques or different input interfaces, just to name a few. Numerous generated instances have been tested in software simulations and mapped and tested onto a commercial FPGA platform. Obtained results proved that a generator of this kind can legitimately be compared with custom designed NCO modules, both in terms of performance and resource utilization.