I am using AD9833 to generate a 134kHz square wave. MCLK=11.0092MHz. The output square wave does not have uniform period. Eight pulses have the same period and then the next one has slightly longer period. Later, I found out the difference is one clock cycle, or 91ns. It does not change with output frequency. I have tried from 10kHz to 150 kHz with the same results. Any ideas?