FIELD: instruments, in particular, devices for selection of same phase and opposite phase signals in precision infra-low frequency devices. SUBSTANCE: device has serial circuit of divider 3, second comparison unit 6 and first comparison unit 5. Inputs of unit 3 are connected to device inputs. Device output is connected to output of unit 5. Output of third is connected through averaging unit 4 to second inputs of second comparison unit 6 and first comparison unit 5. EFFECT: increased dynamic range of input signals. 1 dwg
