Sensor input reference level adjustment function Maximum output signal level control: -15 to 0 dB Minimum output signal level control: -18 to -3 dB Sample time setting: 10 s, 15 s, 20 s, 30 s, 1 min, 2 min, 3 min, 5 min Gain ratio setting (Ambient noise: Output signal level): 6:3, 5:3, 4:3, 3:3, 3:4, 3:5, 3:6, 6:-3, 5:-3, 4:-3, 3:-3, 3:-4, 3:-5, 3:-6