Abstract: An ideal software radio needs efficient high speed digital down converters. The common approach for digital down conversion (DDC) is the so-called ROM table approach where the samples of the input signal are multiplied with amplitude values of the sine-and cosine-function stored in ROM. To achieve high resolution, this technique requires a large look-up table which means large chip area, high power consumption, lower speed, and increased costs.In this paper, a CORDIC-based direct digital frequency synthesizer is described. It is able to reduce the size of the look-up table considerably.

Key words: CORDIC, earth station, DDFS, SFDR