Extracting in-phase and quadrature signal components from a bandlimited real signal using a closed form optimal (MSE) halfband multirate filter design and its implementation on the Motorola DSP56001/DSP56ADC16

摘要

Extraction of the in-phase (I) and quadrature (Q) components from an RF signal is an important problem in radar and communication systems. In analog systems, the image spur suppression is a function of the phase and amplitude balance between the mixers and splitters in the two channel of the I/Q demodulation network. In the proposed system, an all digital scheme is described that allows arbitrary image spur rejection to be achieved by increasing the filter coder. An MMSE optimal FIR halfband filter is proposed and results are presented from a real-time implementation on the Motorola DSP56001 digital signal processor and the DSP56ADC16 delta-sigma A/D converter.