The AD9957's datasheet says that encoding and pulse shaping of symbols must be implemented before the data is presented to the input of the AD9957. What if I ignore the pulse shaping operation?
The purpose of pulse shaping is to limit the effective bandwidth of the signal since our sampling rate is finite. We need to ensure that no spectral components exist beyond the nyquist frequency. So if we don't introduce pulse shaping, spurs that exist beyond nyquist might foldback to the zone below nyquist which could negatively affect our sampled signal.