Design and FPGA Implementation of a Reconfigurable Digital Down Converter for Wideband Applications
This brief presents a field-programmable gate array-based implementation of a reconfigurable digital down converter (DDC) that can process input bandwidth of up to 3.6 GHz and provide a flexible down-converted output. The proposed DDC consists of a mixer and a resampling filter. The resampling filter can work at much higher clock rate. The reason is that all the single-cycle recursive loops in the re sampling filter are pipelined by using either real/imaginary part-time multiplexing or parallel processing technique. With features like arbitrary sampling rate conversion, and dynamic configuration, the proposed design is highly flexible, so that it can generate a down-converted output with sampling rate, selectable within the range of 1 kS/s–225 MS/s. Moreover, the flexibility is further improved by being able to specify the output sampling rate and center frequency to a resolution of less than 1 S/s. The experimental results show that the proposed design can achieve the same functionality as the existing work but with fewer hardware resources.