I am using Terasic ADA AD/DA development board (AD9248). I am interested in using the ADC on the board in a single ended output source for low-frequency signals and even DC measurements. However, the board is designed in an AC coupled manner (see attached). However, when I am trying to bypass the transformers and connect directly the signal to Vin+ and Vin- to GND (single ended) I get an offset when no signal is connected. Is this correct way to connect a dc signal in a single ended mode? Is there schematic for my application?