AD7705/AD7706 datasheet describe that the AD7705 is 2 fully differential input channel ADCs. But this procedure is not clear how to proceed in the schematic.
AD7705
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The AD7705 / AD7706 are complete analog front ends for low frequency measurement applications. These 2-/3-channel devices can accept low level input signals...
Datasheet
AD7705 on Analog.com
AD7705/AD7706 datasheet describe that the AD7705 is 2 fully differential input channel ADCs. But this procedure is not clear how to proceed in the schematic.