How do I modify the speed of the Sawtooth in the AD9106?
The AD9106 TxDAC® and waveform generator is a high performance, quad digital-to-analog converter (DAC) integrating on-chip pattern memory for complex waveform...
AD9106 on Analog.com
If the SAW_STEPx registers are greater than 1, then you can reduce that setting; or you can increase clock rate. Another option is to use the RAM instead of the saw-tooth generator, which would give you the option of controlling step size between samples.