Along with the frequency of interest, harmonics of the fundamental frequency and images of the MCLK frequency are present at the output of a DDS device. SFDR refers to the largest spur or harmonic present in the band of interest. The wide-band SFDR gives the magnitude of the largest harmonic or spur relative to the magnitude of the fundamental frequency in the bandwidth ±2 MHz about the fundamental frequency. The narrowband SFDR gives the attenuation of the largest spur or harmonic in a bandwidth of ±50 kHz about the fundamental frequency.