Design and Implementation of DDC Based on Walsh Transform for HF Radar Receiver

Abstract

This paper studies the design and multiplierless realization of a digital down converter (DDC) in a high frequency (HF) radar receiver. The novel structure mainly consists of a fast Walsh transform (FWT) and an inverse fast Walsh transform (IFWT), both of which can be implemented using only addition and subtraction. Because the transform kernels of the FWT and the IFWT are the same, the implementation complexity of the DDC is significantly reduced. Simulation and field test results are given to demonstrate that the proposed method outperforms the common method and is suited for real-time signal processing of software digital down conversion in a digital signal processor (DSP), such as the ADSP21060.