Disclosed is an implantable device for controllably delivering neural stimuli. The device comprises a
pulse generator configured to deliver neural stimuli via one or more stimulation electrodes to a
neural pathway of a patient. The device comprises measurement circuitry configured to capture
signal windows from signals sensed on the
neural pathway by one or more measurement electrodes, wherein the measurement circuitry comprises a configurable compound
amplifier configured to amplify the captured
signal windows. The device is configured to control the
pulse generator to deliver a neural stimulus according to one or more stimulus parameters, measure a characteristic of an evoked neural response in an amplified captured
signal window subsequent to the delivery of the neural stimulus, determine a feedback variable from the measured characteristic of the evoked neural response and adjust the one or more stimulus parameters so as to maintain the feedback variable at or near a target value.