Interpolation based Direct Digital Frequency Synthesis for wireless communications

In this paper, a compact architecture for direct digital frequency synthesis (DDFS) is presented. It uses a smaller lookup table for sine and cosine functions compared to existing architectures, with minimal hardware overhead. The computation of the sinusoidal values is performed by a parabolic interpolation structure, thus only interpolation coefficients need to be stored in the Read-Only Memory (ROM). A DDFS with 64 dBc SFDR, 10-bit output resolution and 32 bit phase accumulator requires only 104 bits of ROM storage. The ROM size is consistently less than 1 Kbits for SFDR up to 85 dBc.