Single DDS which has capabilities of AD9834 and AD9102

Hi Antonius 

Would you have recommendations for this? the requirement is a 1 Hz resolution but unfortunately the AD9102 is not characterized for low frequencies.

I see no problem using the AD9102 at low frequency, but this requires the clock input and DAC output to be DC coupled, which is different from the solution used in the evaluation board. The DAC has been characterized in DC and the precision figures are given in the datasheet. The master clock has to be lowered so that the pattern memory can hold the required pattern length. The caveat is the increasing HD2 distortion at low frequency. This may be caused by the D/A glitch impulse that is not described in the datasheet.

Should mere shorting of clock input and DAC output will suffice?

Removing the capacitors is not enough for the clock because the signal must be biased around 0.9V. Additional reworks are needed to provide the DC bias point. Before doing this, check the lower cutoff frequency of the balun and the capacitors, as it may work in your particular case.

For the DAC output, capacitors can be removed but the DAC signal will have a DC bias component, so the output must be connected to a high impedance instrument.

Thanks Antonius, I will check that, will keep you posted on my findings.