Apparatus, including a multiplexer, having a firstoutput and multiple first inputs receiving analog inputsignals and an analog feedback signal and cycling throughand selecting the signals for transfer in sequentialsignal groupings to the first output. The apparatus alsoincludes an amplification circuit, having a second outputand a second input connected to the multiplexer firstoutput, that amplifies signals corresponding to theanalog input signals with a selected gain so as togenerate respective amplified analog signals at thesecond output. Circuitry selects a characteristic of therespective amplified analog signals from an initialsignal grouping, feeds the characteristic back for inputto the multiplexer as the analog feedback signal, selectsa subsequent characteristic of the respective amplifiedanalog signals from a subsequent signal grouping, andadjusts the amplification circuit gain so that the analogfeedback signal and the subsequent characteristic havethe same amplitude.
