GBS Elektronik MCA-527 How to do an optimum setup - Manual (Page 2)

Positive preamplifier signal, also the amplitude is acceptable.
Check if such signals are present. If the pulses point downwards, set input polarity to negative.
Negative preamplifier signal. In this case, input polarity should be set to negative, and also it is possible to
increase coarse gain by another step.