The adc card consists of three parts:1. the analog input which is used to condition the input signal; 2.the adc convertor chip or device which do the function of analog to digital convert;3.the digital output which usually includes the DSP function for
digital signal preprocess.
there must be an analog part....gates are only for digital logic...
even if it is done on an FPGA, an external analog part must be included....while the other processing can be done on FPGA