A method for signal gain adjustment in a multi-port, digital distributed antenna system uses a sorter to sort received signals in ascending order according to their signal levels. In one embodiment, a three-dimensional pictogram representing anatomy shown in a medical image is displayed along with a marker that represents a medical instrument used to create the medical image. The first capacitor generates a first direct current voltage according to an X-axis component, a Y-axis component, and a Z-axis component of the signal.